OBJECTIVETo study the effects of PI3K/Akt signaling pathway inhibitor wortmannin on long-term learning and memory abilities in neonatal rats with hypoxic-ischemic brain damage (HIBD).

METHODSForty-eight neonatal rats were randomly assigned to blank control (n=8), sham-operated (n=8), HIBD model (n=10), HIBD+DMSO (dimethyl sulfoxide, n=8) and HIBD+wortmannin groups (n=8). Wortmannin (2 μL) was injected to the left hippocampus 30 minutes before HIBD inducement in the HIBD+wortmannin group. The Morris water maze test was used to examine the long-term learning and memory abilities at the age of 28 days.

RESULTSWith the increased number of swimming, the escape latency was shortened in various groups. From the second day, the escape latency in the HIBD+wortmannin group was significantly longer than that in the sham-operated and the blank control groups (P<0.05), and the differences increased with the time. On the fourth day, there were significant differences in the escape latency between the HIBD+wortmannin group and the HIBD+DMSO group as well as the HIBD model group (P<0.05). On the eighth day (retention trial), there were the most obvious differences in the escape latency between the HIBD+wortmannin group with the other four groups. In the space exploration test, the number of times crossing the former platform location within 120 seconds after removing the platform in the HIBD+DMSO and the HIBD model group was lower than the sham-operated and the blank control groups (P<0.05). The HIBD+wortmannin group showed lower number of times crossing the former platform location compared with the HIBD+DMSO and the HIBD model groups (P<0.05), as well as the sham-operated and the blank control groups (P<0.01).

CONCLUSIONSP13K/Akt signaling pathway inhibitor wortmannin can aggravate the cognitive impairments, thus affecting adversely long-term learning and memory abilities in neonatal rats with HIBD.