Action of Akt Pathway on La-Induced Hippocampal Neuron Apoptosis of Rats in the Growth Stage.

Abstract

This study investigated the influences of lanthanum (La) exposure on learning and memory and the expression of apoptosis-related proteins in offspring rats. Wistar female rats were randomly divided into a control group (NC) and 0.25%, 0.5% and 1.0% LaCl3 treatment groups, with eight per group. La dye was transmitted to offspring rats through parental blood circulation and breast milk before delactation and through water drinking after delectation. Offspring rats were killed at 14, 28 and 42days after birth. Hippocampal neurons were observed by microscope, and apoptosis and necrosis were tested. The expression levels of apoptosis-related proteins were detected by Western blot, and Morris water maze experiments were used to measure learning and memory abilities. LaCl3 groups showed longer escape latency periods and swimming distances than the NC group (p < 0.05). The 1.0% LaCl3 group passed across the target quadrants and platforms more times and stayed in the target quadrants for less time, than the NC group (p < 0.05). At 42days, the apoptosis rate and necrosis in the hippocampus of the 1.0% LaCl3 group were significantly higher than those of other groups. There was a significant difference among LaCl3 groups in terms of protein expressions measured in the hippocampus. In LaCl3 groups, caspase-3 and caspase-9 were significantly higher than in the NC group (p < 0.05). Therefore, La exposure can promote neuronal apoptosis by regulating the protein expressions of Akt, Bcl-2, Bcl-xl, Bax, Bad, caspase-3 and caspase-9, thus damaging learning and memory and the hippocampal neurons of offspring rats.