Changes in rat testis morphology and androgen receptor expression around the age of puberty

Androgens are the keystone in fertility and intact sexual functions in males. It exerts its actions via androgen receptors extensively present in testicular cells, only its presence in germ cells is controversial. The alteration of androgen receptors in different testicular cells is usually accompanied by different sexual disorders. On the other hand, many sexual disorders are treated with androgens. Puberty, being the juncture of hormonal blossom, is an important stage to evaluate the evolution of testicular cells including androgen receptors. The aim of the work was to investigate the morphological and androgen receptor changes in different testicular cells during puberty in the rat testis using histological and immunohistochemical techniques.

This study was carried out on 45 male albino rats (Sprague-Dawley). The rats were divided into three age groups; group I (prepubertal) 21 days old, group II (peripubertal) 35 days and group III (postpubertal) 90 days old. The rat testes were examined histologically and immuneohistochemically. Cells and androgen receptors were counted using Leica Qwin 500 image analyzer computer system. Data were analyzed using univariate ANOVA and Bonferroni post hoc test.

Histological examination of the different ages showed developmental changes of different testicular cells. Immunohistochemical examination revealed the presence of AR in spermatogenic cells in pubertal and postpubertal groups and partially in prepubertal group. AR was clearly expressed in both Sertoli and Leydig cells in the three groups. The maximum expression in Sertoli cells was at 90 days while that of Leydig cells was at the age of 35 days.

Androgen receptors should not be excluded as an effective factor on germ cells through its direct action on AR, clearly expressed in spermatogenic cells and its surge at the age of puberty. Studies and treatments should respect the AR expected levels according to age in other testicular cells as well. Sertoli cells show a linear increase of AR expression throughout life, while Leydig cells show a peak at the age of puberty.