Effect of Zinc Supplementation of Pregnant Rats on Short-term & Long-term Memory of Their Offspring

Objective: To see the dose dependent effects of zinc chloride on the short-term and long-term memory in a shuttle box (rats). Methodology: Six pair adult wistar rats were taken for this experiment. One group of pregnant rats received a daily oral dose of 20mg/kg Zn as zinc chloride and the remaining groups received a daily oral dose of (30, 50, 70,100mg/kg) zinc chloride for two weeks by gavage. One month after birth, a shuttle box was used to test short-term and long-term memory. Two criteria were considered to behavioral test, including latency in entering dark chamber and time spent in the dark chamber. Result: This experiment showed that oral administration of ZnCl2 with (20, 30, 50 mg/kg/day) doses after 2 weeks at the stage of pregnancy, can improve the working memory of their offspring (p<0.05). Where as ZnCl2 with 30mg/kg/day dose has been more effective than other doses (p<0.001). But rat which received ZnCl2 with 100mg/kg/day at the stage of pregnancy, has shown significant impairment in working (short-term) memory of their offspring (p<0.05) and there was no significant difference in reference (long-term) memory 3 for any of groups. Conclusion: This study has demonstrated that zinc chloride consumption with 30mg/kg/day dose for two weeks at the stage of pregnancy in rats, has positive effect on short-term memory on their offspring. But consumption of enhanced zinc 100mg/kg/day in pregnant rats can cause short-term memory impairment. On the other hand, zinc supplementation such as zinc chloride has no effect on long-term memory.