The Effects of Estrogen on Passive Avoidance Memory Impairment Induced by Acute Kidney Injury in Ovariectomized Rats

The aim of this study was to evaluate the effects of acute kidney injury (AKI) and mediatory role of the estrogen on passive avoidance memory in ovariectomized rats. Frothy ovariectomized Wistar rats were subjected to sham-vehicle, sham-estrogen, renal ischemia reperfusion (RIR)-vehicle, and RIR-estrogen groups. AKI was induced by ischemia reperfusion. Estrogen (200 μg/kg in 0.2 ml/100 g body weight) was injected subcutaneously once a week for four weeks. Then, passive avoidance memory was assessed. AKI resulted a significant decrease in the mean latency of entering the dark chamber (P < 0.010). Although, estrogen therapy following AKI led to elevated blood urea nitrogen (BUN) and creatinine, but, there was no significant difference in the delay in entering the dark chamber in RIR-estrogen group compared to RIR-vehicle group (P = 0.100). The results showed that AKI could have a deleterious effect on passive avoidance memory. However, the studied dose of estrogen cannot prevent passive avoidance memory impairment induced by AKI.