Expression of Connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development

Abstract

Connexin 43 (Cx43) is the most abundant and ubiquitously distributed gap junction protein in testicular cells. Lack of Cx43 expression results in male infertility. We investigated whether Cx43 is expressed and regulated in Leydig, Sertoli and germinal cells at different stages of postnatal development. Cx43 was detected using three different antibodies shown by immunoblotting to be highly specific. At different postnatal ages Cx43 localization was compared in serial or double labeled testicular cryosections with immunocytochemical distribution of steroidogenic enzyme, 3 ␤hidroxysteroid-dehydrogenase (3␤HSD), Mullerian inhibitory hormone (MIH), and germinal nuclear cell antigen (GNCA1), which are specific markers of interstitial Leydig, Sertoli and germinal cells, respectively. In the interstitium, round cell clumps (RCC) with lipid droplets positive for 3␤HSD and Cx43 were frequently found at intertubular areas at birth and Cx43 was mainly localized at cell membrane appositions. From day 3, the number and size of 3␤HSD-positive RCC started to decrease, and reached a minimum at 7-14 dpp; Cx43 expressed by them is progressively downregulated. From day 21 an increase in the size and number of RCC positive for Cx43 and 3␤HSD was found that continued at 24, 26 and 28 days and reached a maximum at 35 and 60 dpp. Biphasic expression of interstitial Cx43 and 3␤HSD was also found to be positively and temporally correlated with fluctuations in intratesticular testosterone content at all ages studied. In the seminiferous cord (SC), Cx43 was expressed at birth between adjacent Sertoli cells (MIH positive) localized at the periphery, as well as in their cytoplasm projections that surround centrally localized gonocytes. From days 3 to 7, Cx43 labeling increased in Sertoli cells mainly at their apical border. At day 14, Cx43 distribution in Sertoli cells changed from apical to basal in parallel to migration of germinal (GNCA1-positive) cells from the periphery to the center of the SC. At all these ages, Cx43 was also localized at cell borders between Sertoli and germinal cells. In conclusion, this study demonstrates that Cx43 in Leydig cells is regulated during postnatal development in an age and functional dependent manner. In the tubule, it is demonstrated that Cx43 is modulated in Sertoli cells during the neonatal and prepubertal period. We also provide evidence for the first time that Cx43-gap junctions communicate between Sertoli and germinal cells before and during the first wave of spermatogenesis. Anat Rec 264: [13][14][15][16][17][18][19][20][21][22][23][24] 2001.

Testicular connexin 43, a precocious molecular target for the effect of environmental toxicants on male fertility

“…In fetal and newborn rats, and at the time of initiation of spermatogenesis, Cx43 is present between Leydig cells, between Sertoli cells and between Sertoli and germ cells. [41][42][43] During this critical period of testicular development, Cx43 is first detected as separate dots or a filiformlike network (Fig. 2), which shifts from the apical to the basal regions of seminiferous tubules.…”

“…2), which shifts from the apical to the basal regions of seminiferous tubules. 42,44,45 From postnatal day 12 and thereafter, Cx43 appears as an intense and focal band distributed close to the base of the seminiferous tubule (Fig. 2).…”

Leydig cell function in mice lacking connexin43

“…It is the most abundant gap junction protein in the mouse testis, and so far the only one identified in Leydig cells (Perez-Armendariz et al 1994, Varanda & de Carvalho 1994, Bravo-Moreno et al 2001, Risley et al 2002. Deletion of the Gja1 gene that encodes Cx43 causes a lethal cardiac malformation: mutant fetuses develop to term but die of asphyxiation soon after birth (Reaume et al 1995).…”

Age‐dependent pattern of connexin43 expression in testes of European bison (Bison bonasus, L.)

“…Further observations on immature bison testes revealed only small sites of Cx43 staining localized in the basal compartment of seminiferous tubules, which is not the case in testes of immature rats and mice, in which abundant punctuate and linear arrays of Cx43 have been observed (Batias et al, 2000;Bravo-Moreno et al, 2001). Interestingly, in testes of guinea pig the Cx43 labeling was not detected within the seminiferous tubules before the onset of spermatogenesis (Pelletier,'95).…”