Specific Staining of Sertoli Cell Nuclei and Evaluation of Sertoli Cell Number and Proliferative Activity in Meishan and White Composite Boars During the Neonatal Period1

Abstract

The positive relationship between Sertoli cell number and testicular size emphasizes the importance of determining factors involved in the regulation of the Sertoli cell population. Based on data from other species and indirect evidence in the boar, it is generally accepted that porcine Sertoli cells proliferate rapidly throughout the early postnatal period. However, direct evaluation of Sertoli cell number and the proliferative activity of Sertoli cells during the early postnatal period in boars have not been reported. Stereological enumeration of Sertoli cells is a labor-intensive process and would be greatly facilitated by a marker for these cells especially in the sexually mature male. Thus, the first objective of this study was to determine if expression of the transcription factor GATA-4 is an effective marker for fetal, postnatal, and adult Sertoli cells to facilitate enumeration procedures. The second objective was to evaluate the proliferative activity and growth of the Sertoli cell population in neonatal White Composite and Meishan boars, known to differ in mature testis size and Sertoli cell number, to determine the importance of this developmental period for the adult Sertoli cell population. GATA-4 was abundantly expressed by Sertoli cells throughout fetal and prepubertal stages of development and specifically stained both type A and B Sertoli cell nuclei in the sexually mature boar. Immunoreactivity was never observed in the germ cells regardless of their stage of development, illustrating that GATA-4 is a useful marker for both developing and adult Sertoli cells in the boar. Testicular size did not differ between breeds on Day 1 postpartum, but by 14 days postpartum White Composite boars had significantly larger testes compared to Meishan boars (P: < 0.001). Similarly, Sertoli cell number did not differ between breeds at 1 day postpartum; however, at 14 days postpartum White Composite boars had a significantly larger Sertoli cell population compared to Meishan boars (P: < 0.05). Surprisingly, despite having more Sertoli cells than Meishan boars at 14 days postpartum, the proportion of actively proliferating Sertoli cells in the White Composite boars was almost 50% less than the Meishan boars. This result illustrates that rapid rates of Sertoli cell proliferation probably occurred prior to 14 days postpartum in the White Composite boars. Collectively, these results illustrate that the relationship between testicular size and Sertoli cell number is manifested very early in the postnatal period for these two breeds. The substantial difference in the size of the Sertoli cell population and their proliferative activity between Meishan and White Composite boars during the early postnatal period emphasizes the importance of this early period for the establishment of the Sertoli cell population and subsequent adult testicular size.

Stimulation of Sertoli cell proliferation: defining the response interval to an inhibitor of estrogen synthesis in the boar

“…This suggests that the letrozole effect is either mediated over a prolonged interval or after 3 weeks postnatally. The lack of an effect of letrozole treatment on 1-day-old boars is of interest because rapid rates of Sertoli proliferation have been reported for this early postnatal interval (McCoard et al 2001). Our data suggest that proliferation during the immediate postnatal interval is not sensitive to aromatase inhibition but becomes responsive after the first 3 weeks of life.…”

Dexrazoxane exacerbates doxorubicin-induced testicular toxicity

“…2B) compared to control. The effect of DEX on testicular reserve and on Sertoli cells was assessed by two immunohistochemical biomarkers: PLZF, which is expressed specifically in A-single (As), A-pair (Ap) and A-aligned (Al) undifferentiated spermatogonia (Phillips et al 2010) and GATA-4, a Sertoli-cells marker (McCoard et al 2001). Our data show that 1 month after DEX administration the number of Sertoli cells and of undifferentiated spermatogonia ( Supplementary Fig.…”

Stereological evaluation of Sertoli cell ontogeny during fetal and neonatal life in two diverse breeds of swine

“…Sections were dried overnight onto glass slides at 37 C and stored at room temperature until staining. Sections were stained immunohistochemically for GATA4, a marker for Sertoli cells, and Ki67 antigen as described previously (McCoard et al 2001a).…”

“…During the first month of life there is a 6-fold increase in the number of Sertoli cells (Franca et al 2000) and between 1 and 14 days of age approximately 15-30% of the total Sertoli cell population are undergoing proliferation (McCoard et al 2001a). Increased follicle-stimulating hormone (FSH) secretion (Lunstra et al 1997) during this time has been assumed to be the stimulus for this proliferation as occurs in rats (Meachem et al 1996, Baker & O'Shaughnessy 2001.…”