Résumé
Objective To study the changes of learning-memory ability and synapse of hippocampus after radiation injuries. Methods Sprague-Dawley rats were grouped according to radiation dose to 20Gy group,30Gy group radiated by linear accelerator and control group were used before radiation and 120 days after radiation. Morris maze test were taken to study the learning and memory ability of rats in each group. Average escape latency and search strategy were scaled and analyzed in each group. The parameters of synapse in CA3 area of hippocampus were studied by using electron microscope and image analyzer. Results AEL of 20Gy group was (41. 17 ±10.76 ) s and score of SS was 27.13 ± 2.34 after 120 days' radiation but AEL of 30 Gy group was (78.49 ± 9.32)s and the score of SS was (23.19 ± 7.65 ) nm. There were significant statistic differences Compared with control group and before radiation (P ＜ 0.05 ). The thickness of PSD of 20 Gy group was ( 22.03 ± 6.84 ) nm after 120days' radiation and (23.19 ± 7.65 )nm in 30 Gy group. There were significant statistic differences compared with control group and before radiation. It was observed that both in 20 Gy and 30 Gy group' s the length of synaptic activity area was shorter,the curvature of synaptic interface was smaller,the width of synaptic cleft and the thickness of PSD was narrower than that of control group. Conclusion There was close relation between the changes of learning-memory ability and synapse of hippocampus after radiation injuries.