磷酸化的丝裂原活化蛋白激酶在大鼠睾丸的表达

目的研究丝裂原活化蛋白激酶(MAPKs)的3个亚家族成员细胞外信号调节激酶(ERK)、c-Jun N-端激酶(JNK)和p38 MAPK的活化形式在睾丸中的定位,了解MAPKs在生精过程中所起的作用。方法免疫组织化学方法检测正常大鼠睾丸中磷酸化的p-ERKJ、NK、p38 MAPK的表达情况。结果正常大鼠睾丸中p-ERK主要分布于精原细胞、细线前期到粗线期的初级精母细胞以及9~12期长形精子细胞的细胞核,p-JNK则主要位于支持细胞与支持细胞、支持细胞与生精细胞(尤其是19期精子细胞)之间,而p-p38 MAPK除了在生精小管的部分细胞胞质中有分布外,其表达最明显的部位是在间质细胞的细胞质。结论ERKJ、NK和p-38 MAPK分别定位于正常大鼠睾丸内的不同部位,提示MAPKs不同的亚家族成员分别在精子发生的不同环节中发挥主要作用。ERK可能参与生精细胞增殖、分化的信号转导,JNK则可能通过调节细胞的黏附而最终影响生精细胞的迁移与精子释放过程,而p38 MAPK除了可能与JNK一起参与精子释放的调节外,最主要的作用可能是睾酮合成分泌的调节。

THE EXPRESSION OF PHOSPHO-MAPKS IN THE ADULT RAT TESTIS

Objective Extracellular signal-regulated kinase(ERK),cJun N-terminal kinase(JNK),and p38 MAPK are three major members of mitogen-activated protein kinases(MAPKs) subfamilies.Clarifying the localization of the three activated MAPKs in testes will help us to understand their functions in spermatogenesis. Methods The expression of phospho-(p-) ERK,p-JNK,p-p38 MAPK was detected in normal adult rat testes by the immunohistochemical method. Results p-ERK,one of the MAPKs,expressed prominently in the nuclei of spermatogonia,spermatocytes(preleptotene to pachytene spermatocytes),and elongating spermatids(step 9-12).While,p-JNK was localized at sites of intraepithelial contact between the Sertoli-Sertoli cells and Sertoli-germ cells(especially step 19 spermatids).Meanwhile,the distribution of p-p38 MAPK,the third member of MAPKs,was a little different.Besides its localization in the seminiferous epithelium,the strongest staining of p-p38 MAPK was presented in the cytoplasm of Leydig cells.Conclusion The three members of MAPKs are distributed differently in normal rat testes,which strongly suggests that they regulate the different processes in spermatogenesis.ERK may be involved in controlling germ cell mitosis,meiosis and spermiogenesis,and JNK may modulate actin dynamics to regulate the migration of spermatocytes and spermatids in seminiferous epithelium.Except being combined with JNK to control the spermiation,p38 MAPK may also have a role in the synthesis of testosterone in Leydig cells.