Antioxidant, Anti-inflammatory and Anticholinergic action of berberine attenuates diabetic encephalopathy: Behavioral and Biochemical evidences

 

Vadivelan Ramachandran, Ibrahim Khan, Sudeep Sugumar, Vikash Sundaram

Department of Pharmacology, JSS College of Pharmacy JSS Academy of Higher Education and Research,

Ooty-643001, The Nilgiris, Tamil Nadu, India.

 

ABSTRACT:

Diabetic encephalopathy, characterized by impaired cognitive functions and neurochemical and structural abnormalities, involves direct neuronal damage caused by intracellular glucose. The present study was designed to investigate the effect of berberine an anti-oxidant and anti-inflammatory molecule, on cognitive functions, oxidative-nitrosative stress and inflammation in streptozotocin (STZ)-induced diabetic rats. STZ-induced diabetic Wistar rats were treated with berberine for 6 weeks at 50 and 100 mg/kg/day. During fifth week of treatment, learning and memory was investigated in single Y-maze and passive avoidance test. At the end of the study biochemical parameters like acetylcholinesterase (AchE) activity, nitrite levels, tumor necrosis factor-alpha (TNF-α) and oxidative stress was measured from cerebral cortex and hippocampus regions of brain. AchE activity was found increased by 56 % in the cerebral cortex of diabetic rat brain. Lipid peroxidation (LPO) levels were increased by 100 % and 95 % in cerebral cortex and hippocampus of diabetic rats, respectively. Nonprotein thiol levels, enzymatic activities of superoxide dismutase and catalase were found decreased in cerebral cortex and hippocampal regions of diabetic rat brain. Nitrite levels in both regions of diabetic brain were increased significantly (P < 0.05) compared to control group. TNF-α, a pro-inflammatory cytokine, was found significantly increased in diabetic rats. Conversely, animal groups treated with significantly attenuated these behavioral and biochemical abnormalities. The results suggest a protective role of berberine against diabetic encephalopathy, which may be sum of its anti-oxidant, anti-cholinesterase, anti-inflammatory and glucose lowering action.

 

 

 

INTRODUCTION:

Diabetes a chronic metabolic disorder characterized by hyperglycemia, affects over 300 million people worldwide and is expected to rise further¹. Diabetes mellitus is a heterogeneous metabolic disorder characterized by chronic hyperglycemia and is associated with long-term complications and produces various dysfunctions in the body. Besides the most common complication of the peripheral neuropathy², there are much more evidences, which demonstrate that diabetes may also have negative impacts on the central nervous system and can cause dysfunction of the central nervous system³.

 

Cognitive dysfunction in diabetic subjects has been recognized since the early 20th century. A wealth of studies described a series of neuropathological and neurobehavioral changes in both type 1 and type 2 diabetic subjects, such as cognitive dysfunction and decline in memory and mental speed⁴. The cognitive deficiency was more pronounced in the elderly and in whom the incidence of dementia appeared to be doubled. These slowly progressive alterations in cerebral function and structure that occur in association with diabetes are referred to as “diabetic encephalopathy” which has been recognized as a complication of diabetes⁵.

 

Oxidative stress and inflammation were proved to play a central role in diabetic encephalopathy. Alongside the increment of reactive oxygen species level during hyperglycemia the activities of glutathione peroxidase and superoxide dismutase are reduced^6,7. The increased oxidative stress in diabetes produced the damage of hippocampus and cortex, which contributed to the morphological abnormalities and memory impairment. The enhanced free radicals either directly damaged the cellular proteins, lipids and nucleic acids to cause cell necrosis or indirectly affected cellular signaling pathways and gene regulation to induce neuronal apoptosis; this contributed to the neuropathology associated with diabetes⁸. The brain may be an important target for free radical attacks leading to lipid peroxidation and/or protein nitration events, as well as the initiation of programmed neuronal death. Antioxidants have been shown to protect neurons against a variety of experimental neurodegenerative conditions. Melatonin and vitamin E were reported to prevent diabetes animals from learning and memory deficiency⁹.

 

Berberine is the principal active compound, originally separated from therapeutic plants, including Phellodendri sp., Coptidis sp., and Berberis sp., with an extended past in the traditional Indian and Chinese medicine¹⁰. Numerous researches have demonstrated several pharmacological and biochemical activities of berberine including the anti-inflammatory, anti-cancer, antidiabetic and anti-diarrhea actions¹¹. The obtained data from previous experiments also indicated that might be used as a useful antioxidant in a variety of pathological conditions¹². It has also been revealed that the Berberine produces neuroprotective effects through its anti-inflammatory, antioxidative and anti-neuronal apoptosis pharmacological properties on the brain ischemia¹³.

 

With this background, the present study was undertaken to investigate whether berberine could ameliorate diabetes-associated cognitive decline and to elucidate the related mechanisms.

 

MATERIALS AND METHODS:

Drugs and chemicals:

Berberine and Streptozotocin was purchased from Fluka Sigma-Aldrich (Mumbai, India). Rat TNF-α ELISA kit was purchased from R&D Systems (USA). All other chemicals used for biochemical estimations were of analytical grade.

 

Animals:

Male Wistar rats (250–280g) of 10–12 weeks age were obtained from the animal house facility JSS College of Pharmacy, Ooty, India. They were housed under standard laboratory conditions, maintained on a 12 h light and dark cycle. All animals had free access to food and water. Experimental protocols were approved from the Institutional Animal Ethical Committee (IAEC) and were conducted according to Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA) guidelines, India.

 

Induction assessment of diabetes:

Diabetes was induced in overnight fasted animals by a single intraperitoneal injection of streptozotocin, freshly dissolved in 0.1 M citrate buffer (pH 4.5) at a dose of 55 mg/kg of body weight. Control rats received an equal volume of citrate buffer. Diabetes was confirmed after 48 h of streptozotocin injection, by estimating plasma glucose levels. The rats having plasma glucose levels more than 250 mg/dl were selected for the present study¹⁴.

 

Treatment schedule:

Selected animals were randomized into four groups (n =10) and received respective treatments for 6 weeks.

Group 1 Normal rats treated with distilled water (o.d., p.o.)

Group 2 Diabetic rats treated with distilled water (o.d., p.o.)

Group 3 Diabetic rats treated with 50 mg/kg of Berberine (o.d., p.o.)

Group 4 Diabetic rats treated with 100 mg/kg of Berberine (o.d., p.o.)

 

Body weight and plasma glucose levels were measured at onset and at the end of the experiment. After 6 weeks treatment, blood samples were collected from anesthetized animals through retro-orbital puncture to obtain serum and plasma. Animals were sacrificed and brains were rapidly removed to isolate cerebral cortex and hippocampus. All samples were immediately stored at -80°C until processed for biochemical estimations.

 

Assessment of learning and memory:

Y-maze test:

Short-term spatial memory performance was assessed by recording spontaneous alternation behavior during a single session in a Y-maze¹⁵. This method is based on the tendency of rodents to enter an arm of a Y-maze that was not explored in the last two choices. Each rat, naive to the maze, was placed at the end of one arm and allowed to move freely through the maze during an 8- min session. The series of arm entries was recorded visually. Arm entry was considered to be completed when the base of the animal’s tail had been completely placed in the arm. Alternation was defined as successive entries into the three arms on overlapping triplet sets. The effect was calculated as percent alternation according to the following formula

 

                                      Number of alterations

Percentage alteration = –––––––––––––––––––x 100(%)

                                      total number of entries^-2

 

Single trial passive avoidance test:

This test was done 3 days after Y-maze task^16,17. The apparatus consisted of an illuminated chamber connected to dark chamber by a guillotine door. Electric shocks were delivered to the grid floor by an isolated stimulator. On the first and second days of testing, each rat was placed on the apparatus and left for 5min to habituate to the apparatus. On the third day, an acquisition trial was performed. Rats were individually placed in the illuminated chamber. After a habituation period (2 min), the guillotine door was opened and after the rat entering the dark chamber, the door was closed and an inescapable scrambled electric shock (40 V for 3 s once) was delivered. In this trial, the initial latency (IL) of entrance into the dark chamber was recorded and rats with IL greater than 60 s were excluded from the study. Twenty-four hours later, each rat was placed in the illuminated chamber for retention trial. The interval between the placement in the illuminated chamber and the entry into the dark chamber was measured as step-through latency (STL, up to a maximum of 600 s as cut-off).

 

Post mitochondrial supernatant preparation:

Cerebral cortex and hippocampus were rinsed with ice cold saline and homogenized in chilled phosphate buffer (pH 7.4). The homogenates were centrifuged at 800×g for 5 min at 4°C to separate the nuclear debris. The supernatant thus obtained was centrifuged at 10, 500×g for 20 min at 4°C to get the post mitochondrial supernatant, which was used to assay acetylcholinesterase, LPO, reduced glutathione, catalase, superoxide dismutase (SOD) activity and nitrite levels.

 

Acetylcholinesterase activity:

Cholinergic dysfunction was assessed by measuring AchE levels in cerebral cortex and hippocampus¹⁸. The assay mixture contained 0.05ml of supernatant, 3ml of 0.01M sodium phosphate buffer (pH 8), 0.10ml of acetylthiocholine iodide and 0.10ml 5, 5, dithiobis (2-nitro benzoic acid) (Ellman reagent). The change in absorbance was measured at 412nm for 5 min. Results were calculated using molar extinction coefficient of chromophore (1.36×104 M⁻¹ cm⁻¹) and expressed as mean ± S.E.M.

 

Assessment of oxidative stress:

The malondialdehyde content, a measure of lipid peroxidation was assayed in the form of Thiobarbituric acid reactive substances (TBARS) by the method of Wills¹⁹, Non-protein by the method of Jollow et al.²⁰, cytosolic superoxide dismutase activity by the method of Kono²¹ and catalase activity was assayed by the method of Claiborne ²².

 

Nitrite estimation:

Nitrite was estimated in the cortex and hippocampus regions using the Greiss reagent and served as an indicator of nitric oxide (NO) production. 500μl of Greiss reagent (1:1 solution of 1 % sulphanilamide in 5% phosphoric acid and 0.1% napthaylamine diamine dihydrochloric acid in water) was added to 100μl of post mitochondrial supernatant and absorbance was measured at 546nm²³. Nitrite concentration was calculated using a standard curve for sodium nitrite. Nitrite levels were expressed as percentage of control.

 

Estimation of tumor necrosis factor-alpha:

TNF-α was estimated using rat TNF-α kit (R&D Systems). It is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) using a microtiter plate reader at 450nm. Concentrations of TNF-α were calculated from plotted standard curve. TNF-α levels were expressed as mean ± S.E.M.

 

Statistical analysis:

Results were expressed as mean±S.E.M. The inter group variation was measured by one-way analysis of variance (ANOVA) followed by Tukey’s test. Statistical significance was considered at P <0.05. The statistical analysis was done using the Graphpad Prism Software version 6.

 

RESULTS:

Effect of berberine on body weight and blood glucose levels:

At the end of the study, highly elevated plasma glucose levels (423±3.42mg/dl) were observed in diabetic animals as compared to the control rats (116±0.96 mg/dl). There was a marked decline in the body weights of streptozotocin-treated rats as compared to control rats (Table 1). Chronic treatment of berberine has significantly (P<0.05) and dose dependently improved the blood glucose levels and body weight of diabetic rats.

 

Table 1: Effect of berberine on body weight and plasma glucose level

All the values are expressed as mean ± SEM

a= Different from control group; b=Different from diabetic group and one another (P<0.05)

 

 

Effect of berberine on learning and memory:

Y-maze test:

In Y-maze test, significant lower (P <0.05) mean percentage alteration was observed in diabetic rats (44%) as compared to control rats (71 %). However, groups treated with berberine at 50 and 100 mg/kg/day dose showed significant (P<0.05) improvement in percentage alternation behavior (Fig. 1a).

 

Single trial passive avoidance test:

The diabetic rats developed significant impairment in acquisition and retention in passive avoidance test. In this respect, the mean IL which is indicative of acquisition in passive avoidance test showed a significant (P <0.05) increase in diabetic group (41 s) as compared to control group (27 s). However, 5 weeks treatment with berberine at 50 and 100 mg/kg/day dose significantly (P <0.05) decreased the IL of diabetic rats (Fig. 1b). Retention of single trial passive avoidance training was compared in control, diabetic and treated rats (Fig. 1c). Regarding STL which indicates retention, there was a significant reduction (P <0.05) in diabetic group (250 s) as compared to control group (450 s). Chronic treatment at both dose levels significantly (P<0.05) attenuated the STL of diabetic rats.

 

Fig. 1 a Effect of treatment on alteration behavior in a single session Y-maze.

b Effect of treatment on IL in acquisition trial on passive avoidance test.

c Effect of treatment on STL in retention trial on passive avoidance test.

d Effect of AVEE treatment on TNF-α release in diabetic rats

Data are expressed as mean±SEM. a=Different from control group; b=Different from diabetic group and one another (P <0.05).

 

Effect of berberine on acetylcholinesterase activity:

No significant change was observed in hippocampal AchE activity among all groups (Fig. 2a). While in diabetic group AchE activity significantly increased (P<0.05) in cerebral cortex compared to control animals. Six weeks treatment of berberine at 50 and 100 mg/kg/day significantly (P<0.05) reversed the elevated AchE activity in the cerebral cortex.

Effect of berberine on nitrosative stress:

Nitrite levels were significantly elevated in hippocampus (P<0.05) and cerebral cortex (P<0.05) of diabetic animals compared to control group (Fig. 2b). Chronic treatment was able to alleviate increased nitrite level significantly (P<0.05) in hippocampus and cerebral cortex.

 

 

Fig. 2 a Effect of chronic treatment on acetylcholinesterase activity in hippocampus and cerebral cortex. b Effect of treatment on nitrite levels in cerebral cortex and hippocampus of diabetic rats.

Data expressed as percentage of control. a=Different from control group; b= Different from diabetic group (P<0.05).

 

Table 2: Effect of berberine on antioxidant levels

All values are expressed as mean±SEM. a=different from control; b=different from diabetic; c, d=different from one another (P<0.05)

 

Effect of berberine on lipid peroxidation:

Thiobarbituric acid reactive substance levels were increased significantly (P <0.05) in cerebral cortex and hippocampus of diabetic rats as compared to control group (Table 2). Chronic treatment with berberine produced a significant (P <0.05) and dose dependent reduction in thiobarbituric acid reactive substance levels in cerebral cortex and hippocampus.

 

Effect of berberine on antioxidant profile:

The reduced glutathione levels, enzyme activity of superoxide dismutase and catalase were significantly (P<0.05) decreased in the cerebral cortex and hippocampus of diabetic rats as compared to control group (Table 2). This reduction was significantly (P<0.05) and dose dependently improved by treatment with berberine (50 and 100mg/kg/day) in both regions of brain.

 

Effect of berberine on tumor necrosis factor-alpha:

Serum TNF-α levels were found significantly elevated (P<0.05) in diabetic rats as compared to control animals. Diabetic animals treated with berberine at 50 and 100 mg/kg/day dose, resulted in significant and dose dependent improvement in serum TNF-α level (Fig. 1d).

 

DISCUSSIONS:

Alterations on insulin or glucose homeostasis, oxidative stress, formation of AGEs, C-peptide deficiency and increased Aβ levels in diabetic brain are accelerating factors in development of cognitive decline in diabetic brain^24,25. Increased intracellular glucose oxidation leads to increase in reactive oxygen species (ROS) production. Overproduction of ROS leads to increase in oxidative stress and neuronal damage by promoting protein oxidation, DNA damage and peroxidation of membrane lipids. This glucose driven oxidative stress in neurons adversely affects the cognition and behavior. Oxidative stress caused by diabetes triggers inflammatory processes, well known inhibitors of neurogenesis. Considering these facts, it can be possible to treat diabetic encephalopathy with single or combination of antioxidants like melatonin, vitamin E, vitamin C, chromium picolinate, tocotrienol, N-acetylcysteine^26,27. In present study, we found, increased lipid peroxidation levels and reduction in glutathione, superoxide dismutase and catalase activity in hippocampus and cerebral cortex of diabetic animals. Increased oxidative stress in diabetic brain is probably responsible for behavioral alterations observed in Y maze and passive avoidance test. Six weeks treatment of berberine modified the levels of lipid peroxides, glutathione, superoxide dismutase and catalase in hippocampus and cerebral cortex in rats. Berberine has excellent antioxidant and radical-scavenging activity. It is a natural source of vitamin C, a known anti-oxidant. In present study, ameliorative effect of on oxidative stress in diabetic brain, is may be due to presence of vitamin C, phenol, cholinergic neurotransmission plays role in learning and memory. AchE is the enzyme responsible for degradation of acetylcholine and terminating its physiological action; therefore cholinergic dysfunction is characterized by increased AchE activity²⁸. Like other reported studies, we also observed significant rise in AchE activity in diabetic cerebral cortex which increase severity of diabetic encephalopathy.

 

It appears that berberine may modulate of cholinergic neurotransmission in diabetic brain by exerting vasicinone mediated direct inhibitory action on AchE. Moreover, down regulation of low-density lipoproteins receptor related protein 1 (LRP1) at blood–brain-barrier is responsible for Aβ accumulation, which accelerate cognitive decline in diabetic brain²⁹. Increased Aβ is responsible for overproduction of NO due to increased expression of inducible nitric oxide synthase³⁰. Physiologically, NO has been involved in neural signalling and synaptic plasticity, regulation of autonomic and osmotic functions, learning and memory.

 

Over production of NO may result in formation of highly reactive peroxynitrite by reacting with free radicals. Highly reactive peroxynitrite is responsible for neuronal cell damage, nitration of synaptic proteins, cholinergic dysfunction and altered signal transduction pathways of cellular regulation³¹. It is known that NO plays a role in up-regulation of glucose transporters in neurons which might be detrimental where increased intracellular glucose leads to an oversupply of electrons in the mitochondrial transfer chain, resulting in mitochondrial membrane hyperpolarization and a further increase in free-radical production³². Current study shows attenuation of nitrosative stress by berberine in diabetic rats, which may be responsible for improved learning and memory in Y maze and single passive avoidance test.

 

The AGE-receptor ligation is also responsible for activation of transcription factor NF-κB, which leads to pro-inflammatory gene expressions and production of inflammatory cytokines like TNF-α, IL-1β, IL-2 and        IL-6³³. Increased TNF-α promotes inflammation mediated cognitive decline in diabetes by increasing microvascular permeability, hypercoagulability and nerve damage^34,35. In present study, TNF-α inhibition is may be part of anti-inflammatory action of berberine.

 

In conclusion, the results from present study demonstrated an impaired learning and memory coupled with increase in AChE, lipid peroxidation and decrease in antioxidant enzyme activity in diabetic rat brain. Chronic treatment alleviate behavioral and biochemical alterations in diabetic rats. This ameliorating effect of berberine on diabetic encephalopathy may be sum of its antioxidant, anti-inflammatory, anticholinesterase and glucose lowering activity.

 

ACKNOWLEDGMENTS:

We acknowledge the generous research infrastructure and supports from Department of Pharmacology (DST-FIST sponsored) JSS College of Pharmacy, JSS Academy of Higher Education & Research, Rocklands, Ooty, The Nilgiris, Tamilnadu, India.

 

CONFLICT OF INTEREST:

No conflict of interest.

 

REFERENCES:

1.      Crosby-Nwaobi R, Sivaprasad S, Forbes A, Crosby-Nwaobi R. A systematic review of the association of diabetic retinopathy and cognitive impairment in people with type 2 diabetes. Diabetes Res Clin Pract. 2012; 96:101-10.

2.      Bloomgarden, Z.T. 2007. Diabetic Neuropathy. Diabetes Care 30, 1027–1032.

3.      Biessels G.J, Staekenborg S, Brunner E, Brayne C, Scheltens P. Risk of dementia in diabetes mellitus: a systematic review. Lancet Neurol. 2006; 5:64-74.

4.      Awad N, Gagnon M, Messier C. The relationship between impaired glucose tolerance, type 2 diabetes, and cognitive function. J. Clin. Exp. Neuropsychol. 2004; 26: 1044-1080.

5.      Sinclair AJ, Girling J, Bayer AJ. Cognitive dysfunction in older subjects with diabetes mellitus: impact on diabetes self-management and use of care services. All Wales Research into Elderly (AWARE) Study. Diabetes Res. Clin. Pract. 2000; 50:203-212.

6.      Mastrocola R, Restivo F, Vercellinatto I, Danni O, Brignardello E, Aragno M, Boccuzzi G. Oxidative and nitrosative stress in brain mitochondria of diabetic rats. J. Endocrinol. 2005; 187: 37-44.

7.      Somfai G.M, Knippel B, Ruzicska E, Stadler K, Toth M, Salacz G, Magyar K, Somogyi A. Soluble semicarbazide-sensitive amine oxidase (SSAO) activity is related to oxidative stress and subchronic inflammation in streptozotocin-induced diabetic rats. Neurochem. Int. 2006; 48: 746-752.

8.      Fukui K, Onodera K, Shinkai T, Suzuki S, Urano S. Impairment of learning and memory in rats caused by oxidative stress and aging, and changes in antioxidative defense systems. Ann. N.Y. Acad. Sci. 2001; 928: 168-175.

9.      Tuzcu M, Baydas G.. Effect of melatonin and vitamin E on diabetes-induced learning and memory impairment in rats. Eur. J. Pharmacol. 2006; 537: 106-110.

10.   Ye M, Fu S, Pi R, He F. Neuropharmacological and pharmacokinetic properties of berberine: a review of recent research. J Pharm Pharm Sci. 2009; 61:831-837.

11.   Gao F, Gao Y, Liu Y-f, Wang L, Li Y-j. Berberine exerts an anticonvulsant effect and ameliorates memory impairment and oxidative stress in a pilocarpine-induced epilepsy model in the rat. Neuropsychiatr Dis Treat. 2014; 10:2139-2145.

12.   Pires ENS, Frozza RL, Hoppe JB, de Melo Menezes B, Salbego CG. Berberine was neuroprotective against an in vitro model of brain ischemia: survival and apoptosis pathways involved. Brain Res. 2014; 1557:26-33.

13.   Moghaddam HK, Baluchnejadmojarad T, Roghani M, Khaksari M, Norouzi P, Ahooie M, et al. ameliorate oxidative stress and astrogliosis in the hippocampus of STZinduced diabetic rats. Mol Neurobiol 2014; 49:820-826.

14.   Kuhad A, Chopra K. Curcumin attenuates diabetic encephalopathy in rats: Behavioral and biochemical evidences. Eur J Pharmacol. 2007; 576: 34-42.

15.   Iwai T, Iinuma Y, Kodani R, Oka J. Neuromedin U inhibits inflammation-mediated memory impairment and neuronal cell death in rodents. Neurosci Res. 2008; 61:113-9.

16.   Baydas G, Nedzvetskii VS, Nerush PA, Kirichenko SV, Yoldas T. Altered expression of NCAM in hippocampus and cortex may underlie memory and learning deficits in rats with streptozotocin induced diabetes mellitus. Life Sci. 2003; 73: 1907-16.

17.   Hasanein P, Shahidi S. Effects of combined treatment with vitamins C and E on passive avoidance learning and memory in diabetic rats. Neurobiol Learn Mem. 2010; 93: 472-8.

18.    Ellman GL, Courtney KD, Andres V, Featherstone RM. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem Pharmacol. 1961; 7: 88-95.

19.   Wills ED. Mechanisms of lipid peroxide formation in animal tissues. Biochem J. 1966; 99: 667-76.

20.   Jollow DJ, Mitchell JR, Zampaglione N, Gillette JR. Bromobenze induced liver necrosis: Protective role of glutathione and evidence for 3, 4-bromobenzenoxide as the hepatotoxic intermediate. Pharmacol. 1974; 11:151-69.

21.   Kono Y. Generation of superoxide radical during autoxidation of hydroxylamine and an assay for superoxide dismutase. Arch Biochem Biophys. 1978; 186:189-95.

22.   Claiborne A. Catalase activity. In: Greenwald RA, Raton B, editors. Handbook of methods for oxygen radical research. Florida: CRC Press; 1985. p. 283-4.

23.   Green LC, Wagner DA, Glogowski J, Skipper PL, Wishnok JS, Tannenbaum SR. Analysis of nitrate, nitrite, and [15N] nitrate in biological fluids. Anal Biochem. 1982; 126: 131-8.

24.   Roriz-Filho JS, Sa-Roriz TM, Rosset I, Camozzato AL, Santos AC, Chaves MLF, et al. (Pre) diabetes, brain aging, and cognition. Biochim Biophys Acta. 2009; 1792: 432-43.

25.   Sima AAF. Encephalopathies: The emerging diabetic complications. Acta Diabetol. 2010; 47:279-93.

26.   Kamboj SS, Chopra K, Sandhir R. Neuroprotective effect of Nacetylcysteine in the development of diabetic encephalopathy in streptozotocin-induced diabetes. Metab Brain Dis. 2008; 23:427-43.

27.   Bhutada P, Mundhada Y, Bansod K, Tawari S, Patil S, Dixit P, et al. Protection of cholinergic and antioxidant system contributes to the effect of ameliorating memory dysfunction in rat model of streptozotocin-induced diabetes. Behav Brain Res. 2011; 220:30-41.

28.   Bhutada P, Mundhada Y, Bansod K, Bhutada C, Tawari S, Dixit P, et al. Ameliorative effect of quercetin on memory dysfunction in streptozotocin-induced diabetic rats. Neurobiol Learn Mem. 2010; 94:293–302

29.   Hong H, Liu LP, Liao JM, Wang TS, Ye FY, Wu J, et al. Downregulation of LPR1 at the blood–brain barrier in streptozotocin-induced diabetic mice. Neuropharmacol. 2009; 56:1054–59.

30.   Liu Y, Liu H, Yang J, Liu X, Lu S, Wen T, et al. Increased amyloid β- peptide (1–40) level in brain of streptozotocin-induced diabetic rats. Neuroscience. 2008; 153:796-802.

31.   Comin D, Gazarini L, Zanoni JN, Milani H, de Oliveira RMW. Vitamin E improves learning performance and changes the expression of nitric oxide-producing neurons in the brains of diabetic rats. Behav Brain Res. 2010; 210: 38–45.

32.   Murray J, Taylor SW, Zhang B, Ghosh SS, Capaldi RA. Oxidative damage to mitochondrial complex I Due to peroxynitrite. J Biol Chem. 2003; 278:37223–30.

33.   Satoh J, Yagihashi S, Toyota T. The possible role of tumor necrosis factor-α in diabetic polyneuropathy. Exp Diabesity Res. 2003; 4:65-71.

34.   Brands AMA, Kessels RPC, de Haan EHF, Kappelle LJ, Biessels GJ. Cerebral dysfunction in type 1 diabetes: Effects of insulin, vascular risk factors and blood-glucose levels. Eur J Pharmacol. 2004; 490: 159–68.66.

35.   Sharma S, Chopra K, Kulkarni SK. Effect of insulin and its combination with resveratrol or curcumin in attenuation of diabetic neuropathic pain: participation of nitric oxide and TNF-alpha. Phytother Res. 2007; 21:278–83.

 

 

 

Received on 13.08.2019          Modified on 10.10.2019

Accepted on 07.12.2019         © RJPT All right reserved