Spermatogenesis in the golden hamster: The role of c‐kit

Abstract

c-kit is related to the family of transmembrane tyrosine kinase receptors. Mutations in genes for either c-kit or its ligand, Steel factor, result in infertility, but the role of c-kit/SCF system in spermatogenesis is not well understood. In this study Western blot analysis together with confocal microscopy were used to follow c-kit expression in hamsters during the first spermatogenic wave in mature animals and in old age. Three antibodies raised against different domains of c-kit were tested on Western Blot. Confocal microscopy was performed after incubation of fixed seminiferous tubules with tested antibodies followed by binding of FITC-labeled secondary antibody. Longitudinal sections of seminiferous tubule were observed by confocal microscopy to determine in which stages of spermatogenesis and in which cell types c-kit was found. C-kit bands of 80,140, and 150 kDa were observed on Western blot, indicating that c-kit is a name related to several proteins sharing some common domains. Only the band of 150 kDa correlated with positive staining of c-kit in tubules using confocal microscopy. We term this protein c-kit150T (150 kDa, testis). We demonstrated that c-kit150T appeared in differentiating hamster spermatogonia at stages VII-VIII of adult spermatogenesis and at day 13-14 during the first spermatogenic wave. It remained attached to the cell until late pachytene. This suggests that c-kit may play a role in preparing the germinal cells to enter meiosis. In order to evaluate the effect of aging on the number of germ cells, B2 spermatogonia/Sertoli cell ratio was calculated in the group of young animals (5-7 months) compared to this ratio in older ones (20-26 months). A significant decrease (P < 0.01) in the number of B2 spermatogonia in the group of old hamsters as compared to young ones was seen. The calculated value for the B2 spermatogonia/Sertoli cell ratio was 5.6 +/- 0.7 in young animals and 3.8 +/- 1.2 in the 20-26 months ones. In addition, decrease in the intensity of staining for c-kit was detected in the old hamsters. These may be the reasons for subfertility in old age and in other cases of testicular disorders.

Proliferation and Apoptosis in Aged and Photoregressed Mammalian Seminiferous Epithelium, with Particular Attention to Rodents and Humans

“…As regards the possible factors regulating spermatogonia proliferative activity, a decrease in c‐kit expression has been documented in aged mice and hamster, which might be linked to epithelium involution (Tanemura et al. 1996; Vigodner et al. 2001).…”

Influence of histological degree of seminiferous tubular degeneration and stage of seminiferous cycle on the proliferation of spermatogonia in aged Syrian hamster (Mesocricetus auratus)

“…Also in human testes, a decrease in the proliferating spermatogonia percentage has been documented in aged individuals with respect to young ones (Kimura et al ., ). Moreover, a decrease in c‐kit expression has been documented in aged mice and hamster, which might be linked to epithelium involution (Tanemura et al ., ; Vigodner et al ., ). These observations suggest the relation of ageing of the seminiferous epithelium with decreased proliferative activity of differentiated spermatogonia probably because they express c‐kit receptors (Meachem et al ., ).…”

The SCF/c-KIT system in the male: Survival strategies in fertility and cancer

“…c‐KIT abundance is highest in spermatogonia, although its expression pattern seems to vary according to the differentiation state of this cell type (Strohmeyer et al, ; Bokemeyer et al, ; Schrans‐Stassen et al, ; Unni et al, ; Muciaccia et al, ). As described above, c‐KIT is expressed in differentiated type A spermatogonia, intermediate spermatogonia, and type B spermatogonia, but remains undetectable in undifferentiated cells (Yoshinaga et al, ; Dym et al, ; Ali et al, ; Schrans‐Stassen et al, ; Vigodner et al, ; Unni et al, ). The majority of published studies indicate that the highest expression of c‐KIT occurs in earlier and later stages of spermatogenesis—respectively, in spermatogonia and early spermatocytes (Yoshinaga et al, ; Strohmeyer et al, ; Bokemeyer et al, ; Unni et al, ; Muciaccia et al, ) and in round spermatids and spermatozoa (Strohmeyer et al, ; Sandlow et al, 1996, 1997; Unni et al, ; Muciaccia et al, ).…”

“…While some authors failed to detect c‐KIT in late spermatocytes (Yoshinaga et al, ; Sandlow et al, ; Vigodner et al, ; Unni et al, ; Muciaccia et al, ), others documented its expression in them (Vincent et al, ; Vigodner et al, ; Guerif et al, ). Similarly, Vigodner et al () did not observe c‐KIT in round spermatids, whereas other studies demonstrated its presence in them (Sandlow et al, 1996, 1997; Unni et al, ; Muciaccia et al, ). c‐KIT was specifically detected in the acrosomal granules of round spermatids and in the acrosome region of testicular human, rat, and mouse spermatozoa (Sandlow et al, 1996, 1997; Unni et al, ).…”