Improving effect of testicular tissue graft on impaired learning and memory in endocrine recession mice / 中华器官移植杂志

ABSTRACT

Objective To study the improving effect of testicular tissue graft on impaired learning and memory in endocrine recession mice,and to explore the possible mechanisms.Method Forty Kunming male mice were randomly divided into four groups by random number tablesham operation group,castration group,androgen (30 mg/kg) control group and testicular tissue graft group.The bilateral testes of mice were cut off to establish castrated mouse model.After modeling,the back subcutaneous muscle layers of castrated mice were implanted on the allogeneic testicular tissue blocks in graft group.Androgen group mice were intragastrically administrated with androgen for three months,and other two groups of mice were given an equal volume of normal saline At the end of treatment,the levels of serum testosterone in each group of mice were measured by ELISA.Learning and memory abilities of the mice were assessed by Morris water maze behavioral test.Morphological changes in the hippocampal CA1 region were observed through hematoxylin-eosin staining (HE).The expression levels of AR and apoptosis-related proteins (Bcl-2,Bax,caspase-3 and caspase-9) in the brain were detected by Westem blotting.Result As compared with castration group,the levels of serum testosterone in graft group were increased significantly (P＜0.01),learning and memory abilities were greatly strengthened (P ＜ 0.01),the morphological structures in hippocampal CA1 neurons were improved,and the expression levels of Bax,caspase-3 and caspase-9 were significantly reduced (P＜0.01),while the expression levels of AR and Bcl-2 had obvious enhancements (P ＜0.01).Conelusion Testicular tissue graft can improve learning and memory ability probably by secreting endogenous testosterone which will bind with androgen receptor in the brain,then regulating the expression of neuronal apoptosis related genes,increasing Bcl-2 protein level and reducing the expression of Bax,caspase-3 and caspase-9 protein,and finally inhibiting neuronal apoptosis.