Vitamin D3 Improves Decline in Cognitive Function and Cholinergic Transmission in Prefrontal Cortex of Streptozotocin-Induced Diabetic Rats
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- Category: Vol. 81, December 2013
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Vitamin D3 Improves Decline in Cognitive Function and Cholinergic Transmission in Prefrontal Cortex of Streptozotocin-Induced Diabetic Rats, ZIENAB ALREFAIE
Abstract
Complications of diabetes mellitus include cognitive impairments and functional changes in the brain. Vitamin D has shown potential protective effects against many non-skeletal disorders. The present study aimed to investigate the effect of diabetes mellitus on episodic memory and cholinergic transmission in the prefrontal cortex. In addition, the possible beneficial effects of vitamin D3 were also assessed.
Methods: 30 male Wistar rats (150-200gm) were included into control, diabetic and diabetic supplemented with vitamin D3 groups. Diabetes was induced by single intraperitoneal injection of streptozotocin (stz) 45mg/kg in citrate buffer. Vitamin D3 was administered orally in a dose of 500 IU/kg/day in corn oil. 10 weeks after the onset of the treatment, rats were subjected to novel object recognition test to examine for episodic memory. Animals were sacrificed under diethyl ether anathesia and prefrontal cortices were dissected to measure the activity of choline acetyl transferase (CAT) and acetyle choline esterase (ACE) enzymes to assess for cholin-ergic transmission.
Results: Diabetic rats spent significantly less time explor-ing the novel object in novel object recognition test compared to control animals. Vitamin D3 significantly attenuated the diabetes-induced impairment such that animals again spent significantly more time exploring the novel object. The CAT activity was significantly decreased in diabetic animals while the ACE activity was significantly increased compared to control non-diabetic animals. Diabetes-induced alterations in enzyme activity in the prefrontal cortex were mitigated by vitamin D3 supplementation.
Conclusion: The present findings demonstrate that vitamin D3 improved the decline in cognitive function observed in diabetic animals. It is possible that this effect was mediated through enhancing the prefrontal cortex cholinergic transmis-sion. The present work supports the importance of vitamin D3 supplementation to alleviate cognitive impairment associ-ated with diabetes mellitus.