Immunohistochemical measurement and expression of Mcl-1 in infertile testes

The diagnosis of azoospermia represents a major challenge to andrologists as this condition may occur despite normal spermatogenesis and genital tracts. Myeloid cell leukemia-1 (Mcl-1) is a member of the Bcl-2 family of proteins involved in regulation of apoptosis in various cell types. This study aimed to investigate the immunohistochemical expression of Mcl-1 in testicular biopsies of subjects with azoospermia. Eighty-six cases with azoospermia were obtained from 509 infertile patients admitted to the Andrology Unit of the Zagazig University Hospitals from January 2010 to December 2011. Biopsies were diagnosed and classified using H&E-stained slide sections. The specimens were subjected to immunohistochemical staining for Mcl-1 and examined through light microscopy. Forty-five cases of maturation arrest (25 at spermatids and 20 at the spermatocytes), 31 cases of hypospermatogenesis (20 moderate and 11 severe), 5 cases of Sertoli cell-only syndrome, 2 cases of basement membrane hyalinization, and 1 case of tubular and peritubular sclerosis were observed. Normal spermatogenesis was detected in 2 cases. A strong positive immunoreaction in Leydig cells was observed among all investigated specimens. A moderate reaction was detected in spermatocytes and spermatozoa in cases of normal spermatogenesis and hypospermatogenesis, but a negative reaction was detected in cases of maturation arrest and germ cell aplasia. Apoptosis was found to be associated with decreased rate of spermatogenesis. High apoptosis rates may result in azoospermia, which can occur despite normal spermatogenesis and absence of duct obstruction.