The Effects of Vitamin B12 on Spatial Learning and Memory in Adult Male Rats Model of Alzheimer's Disease

Abstract

Background: Vitamin B12 is a water-soluble vitamin shown to have a positive effect on cognition. This study aimed to examine the effect of Vitamin B12 on spatial learning and memory in electrical lesion model of nucleus basalis magnocellularis (NBM) of Alzheimer's disease. Methods: 49 adult male Wistar rats were divided into seven groups of control, sham (the electrode was entered into the nucleus basalis magnocellularis with no lesion), lesion (which received bilateral electric lesions of nucleus basalis magnocellularis), vehicle (lesion + 0.2 ml saline), and lesion + vitamin B12 (5, 10, and 15 mg/kg intraperitoneally). After one week, the rats were trained to perform the Y-maze task for five days. 25 days after training, a retention test was performed to determine long-term memory. Findings: Bilateral nucleus basalis magnocellularis lesion reduced spatial learning in comparison with control and sham groups (P < 0.001 for both). There was no effect on spatial learning in vehicle group compared with the lesion group. Treatment with vitamin B12 in groups of lesion + 10 mg/kg vitamin B12 (P < 0.05), and lesion + 15 mg/kg vitamin B12 (P < 0.010) significantly improved spatial learning. Moreover, no significant difference was observed between the results in the 5th day of training, and memory retention of the 30th day. Conclusion: Our findings indicated that the bilateral nucleus basalis magnocellularis lesion impaired spatial learning in rats, but vitamin B12 improved the learning in them.

Keywords

• Vitamin B12
• Spatial learning
• Nucleus basalis magnocellularis
• Alzheimer’s disease