Neonatal isolation provokes hippocampal apoptosis and recognition memory impairment in rats

Abstract

Neonatal isolation (NI) has detrimental consequences on the hippocampal neurons of rat neonates. It has been reported to enhance neuronal cell death and impair memory behaviors. We conducted this study to assess the effects of NI on hippocampal apoptosis and recognition memory impairment in the hippocampus of rat neonates. One group of male Wistar rat neonates exposed to NI; rat neonates reared with 1-hour neonatal isolation (NI) for eight consecutive days (P2-P9). On the other hand, the control group reared normally. Novel object recognition test (NOR) test used to evaluate the effects of NI on recognition memory impairment. On day 22 (P22), a TUNEL assay was done. NOR demonstrated that rat neonates who experienced NI had long-term memory deficits (P<0.01). TUNEL assay results showed that NI increased the number of TUNEL positive neurons in CA1, CA3, and DG subfields of the hippocampus (P<0.05, P<0.001, and P<0.001). The present results indicated that NI exerted apoptotic effect and induced recognition memory impairment in the rat neonate’s hippocampus.