Immunolocalization of laminin during postnatal development of the testis, epididymis and vas deferens of albino rat

Background: Disorders of testicular function may have their origins in fetal or early life as a result of abnormal development. Laminin-1 is emerging as the key molecule in early embryonic basement membrane assembly. Accumulating evidence supported the idea that extracellular matrix (ECM) molecules and mesenchymal cells might influence Sertoli and spermatogenic cell functions. Aim of the work: detecting the changes in the distribution and prevalence of laminin-1 assembly during postnatal development of the testis, epididymis and vas deferens in albino rats. Materials and methods: Thirty male albino rats were used and divided into six groups (n= 5 each) according to the age (postnatal day). These were one day, 1 week, 2 weeks, 3 weeks, 4 weeks, and 8 weeks postnatal. Specimens were fixed and processed, sectioned and stained by hematoxylin and eosin and immunohistochemical stain for laminin-1. The area percent of positive laminin immunostaining was measured and results were statistically analyzed. Results: at day one postnatal, the testis was formed of solid un-canalized cords of seminiferous tubules with abundant laminin expression in the cells of the cords. With advancement of development the cords were luminized and the laminin expression declined to involve the basement membrane and the apical portions of the Sertoli cells at the 8th week postnatal. The epididymis at postnatal day one had a small diameter and narrow lumen and laminin expression involved the cytoplasm of the epithelial lining. As development proceeded the expression became confined to the apical portion, the site of stereocilia together with its presence in the basement membranes. The same pattern of changes in laminin expression together with morphological appearance was detected in the vas deferens. Conclusion: The present study was able to demonstrate a change in the distribution as well as the prevalence of laminin-1 immunoreactivity within the testis, epididymis and vas. During the period of postnatal development starting at postnatal day one up to 8 weeks postnatal. This would reflect an essential role for laminin in early postnatal period of development