Intrahippocampal Administration of Vitamin C and Progesterone Attenuates Spatial Learning and Memory Impairments in Multiple Sclerosis Rats
It seems antioxidant and sex hormones are able to protect the multiple sclerosis (MS) rats against spatial memory reduction. Since sex hormones and oxidative stress are affective in the process of multiple sclerosis (MS), as well as cognitive functions, the study evaluates the effects of intrahippocampal injection of vitamin C and progesterone, alone or in combination on spatial memory in multiple sclerosis. Sixty-three (63) male Wistar rats were divided into nine groups (n = 7): control, (saline), sesame oil, lesion (ethidium bromide (EB)), vitamin C (1, 5 mg/kg), progesterone (0.1, 1 μg/μl) and combination therapy. In combination therapy, animals were treated with vitamin C (5 mg/kg) + progesterone (0.01 mg/kg). Animals in experimental groups received different treatments for 7 days. Characteristics of learning and spatial memory were assessed using Morris Water Maze (MWM). The results showed that intrahippocampal injection of ethidium bromide destroys MWM significantly (p<0.05). Vitamin C (5 mg/kg), progesterone (0.1 mg/kg) and vitamin C (5 mg/kg) + progesterone (0.1 mg/kg) significantly decreased latency time and travelled distance (P<0.05) in MS or lesion rats. In comparison with control group, the lesion group decreased and progesterone 0.1 mg/kg + vitamin C 5 mg/kg increased the time and distance in the target quadrant after the platform was removed. In comparison with lesion group, vitamin C (1 and 5 mg/kg), progesterone (0.1 and 1 mg/kg) and vitamin C + progesterone effective doses increased the time and distance in the target quadrant after the platform was removed. The results showed that multiple sclerosis rats had a decreased travelled distance and time spent in target quadrant to find the hidden platform in a MWM task. Vitamin C and progesterone alone improved spatial memory in comparison to lesion group. Effective doses of vitamin C + effective dose of progesterone had more improving effect on memory.