Temporal changes in histomorphology and gene expression in goat testes during postnatal development1,2

Abstract

Testicular cell proliferation and differentiation is critical for development of normal testicular function and male reproductive maturity. The objective of the current study was to evaluate histoarchitecture and expression of genes marking specific cells and important functions as well as testosterone production of the developing goat testes. Testes were harvested from Alpine bucks at 0, 2, 4, 6, and 8 mo of age (n = 5/age group). Paired testes weight increased from 2 to 4 (P < 0.001) and 4 to 6 mo (P < 0.01). The greatest increases in seminiferous tubule and lumen diameters and height of the seminiferous epithelium occurred between 2 and 4 mo (P < 0.001). Genes expressed in haploid germ cells (Protamine1 [PRM1], Outer Dense Fiber protein 2 [ODF2], and Stimulated by Retinoic Acid gene 8 [STRA8]) increased dramatically at the same time (P < 0.001). Expression of other genes decreased (P < 0.05) during testicular maturation. These genes included P450 side chain cleavage (CYP11A1), Sex determining region Y-box 9 (SOX9), Insulin-like Growth Factor 1 Receptor (IGF1R), and Heat Shock Protein A8 (HSPA8). The Glutathione S-Transferase A3 (GSTA3) gene, whose product was recently recognized as a primary enzyme involved in isomerization of androstenedione in man and livestock species including goats, sheep, cattle, pigs, and horses, uniquely peaked in expression at 2 mo (P < 0.05). Follicle-Stimulating Hormone Receptor (FSHR) mRNA abundance tended to steadily decrease with age (P = 0.1), while Luteinizing Hormone Receptor (LHCGR) mRNA abundance in testes was not significantly different across the ages. Testosterone content per gram of testicular tissue varied among individuals. However, testosterone content per testis tended to increase at 6 mo (P = 0.06). In conclusion, major changes in cellular structure and gene expression in goat testes were observed at 4 mo of age, when spermatogenesis was initiated. Male goats mature rapidly and represent a good model species for the study of agents that enhance or impair development of testicular functions.

Role of early life nutrition on the hypothalamic-pituitary-testicular axis of the bull

“…Other studies have reported a decline in FSHR levels in rat and mice testes as they age (Ketelslegers et al 1978). However, this result may be affected by an increase in germ cell population, causing an overall dilution of FSHR (Faucette et al 2014). Given the absence of an effect of plane of nutrition on systemic FSH concentration or indeed FSHβ transcript abundance in the anterior pituitary, in our study, it is not entirely surprising that there was no effect on testicular FSHR expression.…”

Comparison of miRNA and mRNA Expression in Sika Deer Testes With Age

“…Among them, HMGB1, as a paracrine host defense factor in the testis, was translocated from testicular cells and blocking its action by ethyl pyruvate regulated inflammatory reactions in testes and spermatogenic damage ( 68 , 69 ). Testis-specific HSPA8 gene was confirmed to decrease with the development of goat testis, which may be due to dilution by the maturing germ cell population ( 70 ). Lower concentrations of HSPA8 were associated with subfertility in men ( 71 ).…”

Overexpression of DAZL, STRA8, and BOULE Genes and Treatment With BMP4 or Retinoic Acid Modulate the Expression of MSC Overexpressing Germ Cell Genes

“…Moreover, we observed an immune signal associated to STRA8 in the spotted areas across the germinal epithelium in seminiferous tubules, showing a higher intensity in the basal compartment. STRA8 expression levels have been reported to peak at 6 months of age in goat testis and has been associated to the onset of meiosis with the highest intensity levels in preleptotene/early leptotene spermatocytes ( 29 , 30 ). Levels of the BOULE expression in goat has been reported to increase in the adult compared to the immature testis, which may be associated to an increasing number of BOULE positive spermatogonial cells at the adult stage ( 31 ).…”