Role of Onset of Diabetes on Development of Cognitive Impairment in Rats

Abstract Background The risk of cognitive impairment in diabetic patients is increasing in day to day life. One of the reasons for cognitive impairment in diabetic patients is hyperglycemic condition. Hyperglycemia leads to amyloid beta accumulation in brain, aggravates oxidative stress, neuro‐inflammation, and results in mitochondrial dysfunction, which impairs neuronal integrity, and eventually neurodegeneration. These are possible working mechanisms in diabetes‐related cognitive impairment. Further, literature says that, earlier the development of diabetes, greater the chances of developing cognitive impairment. Method Diabetes was induced using streptozotocin in juvenile (3‐6 weeks old), adult (8‐10 weeks old) and aged (30‐34 weeks old) rats. Blood glucose levels were monitored after 10 days of streptozotocin administration. Rats which showed cognitive impairment were treated with insulin or insulin + donepezil. Diabetic rats were evaluated for cognitive impairment in fear conditioning memory task at 3 and 6 weeks after the confirming diabetes. Result The total freezing time decreased in juvenile> adult > aged diabetic rats respectively, when compared with naïve rats. The cognitively impaired diabetic rats treated with insulin + donepezil showed improvement in the associative memory observed from increase in freezing behavior in fear conditioning task. Conclusion Diabetes in the early stages of life may have greater risk for developing cognitive impairment.