Immunohistochemical characterization of normal sertoli and germ cells in post-natal rabbit testes, from neonatal to adult age

In the last decades, human male reproductive pathologies and testicular cancer have increased. During the physiological maturation of the testis, from foetal to adult age, both Sertoli (SCs) and germ cells (GCs) switch from an immature to a mature immunophenotype. The re-expression of markers of immaturity in adult has been reported in numerous pathological conditions affecting the testis, in man as in animal species. Rabbits have been commonly employed for scientific research of human male reproductive system, but reports on rabbit testicular cells markers are few and data about the immunophenotype of normal postnatal SCs and GCs are lacking. The aim of this study was to evaluate the immunohistochemical expression of anti Müllerian Hormone (AMH), Vimentin (VIM), CKAE1/AE3 (CKs), Desmin (DES), Inhibin- (INH-) and Placental Alkaline Phosphatase (PLAP) on normal rabbit testes, from the neonatal to adult age. Twelve neonatal, 17 prepubertal and 7 adult testes were considered in the study. VIM was constantly expressed by SCs independently from the age of the rabbits, AMH and CKs expression in SCs was limited to the neonatal and prepubertal age, and DES and INH- were never expressed by SCs as well as PLAP in GCs. This latter finding indicates the absence of early GCs (gonocytes) in postnatal rabbit testes. The immunolabelling of normal GSc and SCs from rabbit testes revealed analogies with the human testicular phenotype in the different stages of testicular postnatal development. In fact, during maturation, in SCs some markers are maintained, as VIM, while other markers are lost as CKs and AMH. Considering GCs, the absence of early, undeveloped, GCs also parallels with findings in human species. The data obtained from this pivotal study suggest that rabbit could a potential good animal model for human testicular pathologies and encourage further investigations focusing on the immunohistochemical phenotype on rabbit testicular neoplasms.