RÉSUMÉ
Corticosteroids are potent medications that have been extensively used to treat many inflammatory and autoimmune conditions. To study the histological changes that may occur in the prepubertal albino rat testis after administration of dexamethasone and to investigate the possibility of recovery of testis after drug stoppage. Thirty prepubertal male albino rats were used and divided into three equal groups. Group I [control] and group II [dexamethasone-treated] that were injected daily intraperitonealy by dexamethasone [7mg/kg body weight] for 2 weeks. Group III [recovery] were injected daily intraperitonealy with the same dose of dexamethasone for 2 weeks as group II, then left untreated for further 2 weeks. At the time of sacrifice, the testes of all groups were dissected out, processed and stained with H and E. Semithin sections were stained with toluidine blue and ultrathin sections were examined by electron microscope. Histological examination of dexamethasone-treated rats revealed changes in most of the seminiferous tubules. They had lost the normal distribution of their epithelial lining with appearance of several layers of dark type spermatogonia. They were ensheathed by irregular basement membrane. Ultrastructurally, spermatogonia had small irregular nuclei with condensation of heterochromatin and their cytoplasm contained few mitochondria. Some primary spermatocytes showed clumps of heterochromatin in their nuclei and their cytoplasm contained few mitochondria. Other cells were apoptotic. Multiple Sertoli cells appeared with indented nuclei and peripheral marginated heterochromatin. Their cytoplasm showed mitochondria with disrupted cristae. Leydig cells appeared with irregular shaped nuclei, contained large heterochromatic masses and their cytoplasm had some electron dense bodies of variable sizes and shapes. The testis of recovery group contained distorted seminiferous tubules with no return to the normal histological structure. The present work showed that dexamethasone injection for 2 weeks produced destructive effects on the structure of prepubertal albino rat testes. Also, this work showed incomplete recovery of these effects after drug stoppage. In clinical practice, therapeutic doses of dexamethasone and periods of administrations must be carefully adjusted specially in younger ages