Long-term vitamin A deficiency induces alteration of adult mouse spermatogenesis and spermatogonial differentiation: direct effect on spermatogonial gene expression and indirect effects via somatic cells

Abstract

The objective of this study was to further understand the genetic mechanisms of Vitamin-A-Deficiency (VAD) induced arrest of spermatogonial stem-cell differentiation. Vitamin A and its derivatives (the retinoids) participate in many physiological processes including vision, cellular differentiation and reproduction. VAD affects spermatogenesis, the subject of our present study. Spermatogenesis is a highly regulated process of differentiation and complex morphologic alterations that leads to the formation of sperm in the seminiferous epithelium. VAD causes early cessation of spermatogenesis, characterized by degeneration of meiotic germ cells, leading to seminiferous tubules containing mostly type A spermatogonia and sertoli cells. These observations led us to the hypothesis that VAD affects not only germ cells but also somatic cells. To investigate the effects of VAD on spermatogenesis in mice we used adult Balb/C mice fed with Control or VAD diet for an extended period of time (6–28 weeks). We first observed the chronology, then the extent of the effects of VAD on the testes. Using microarray analysis of isolated pure populations of spermatogonia, leydig and sertoli cells from control and VAD 18- and 25-week mice, we examined the effects of VAD on gene expression and identified target genes involved in the arrest of spermatogonial differentiation and spermatogenesis. Our results provide a more precise definition of the chronology and magnitude of the consequences of VAD on mouse testes than the previously available literature, and highlight direct and indirect (via somatic cells) effects of VAD on germ cell differentiation.

Long-term dietary intake of excessive vitamin A impairs spermatogenesis in mice

“…However, although there is a small amount of evidences about the long-term effects of VAE on rat spermatogenesis, previous studies focused on the effects on body and reproductive organ weights, which have not been previously well characterized (Lamano Carvalho et al, 1978;Bosakowski et al, 1988). The present study was conducted to investigate whether long-term intake of VAE arrested spermatogenesis in mice, and it demonstrated for the first time the molecular mechanism of spermatogenic arrest, which was partly different from that in vitamin A-deficient mice as reported previously (Boucheron-Houston et al, 2013). The vitamin A intake (1,000 IU/g diet) in the present study was lesser than in previous reports (Bosakowski et al, 1988) and could not cause teratogenicity (10,000 IU/day) (Miller et al, 1998).…”

“…In normal mice testes, the cellular localization of these retinoid receptors has been exclusively studied by in situ hybridization and immunohistochemical analysis (Vernet et al, 2006). Rarβ and Rxrγ mRNA expressed in step 7 and 8 round spermatids (Vernet et al, 2006) in the testes were decreased by VAE intake, identical to the changes induced by vitamin A deficiency (Boucheron-Houston et al, 2013). These results suggested that excess of vitamin A or its deficiency in mice resulted in decreased differentiation of step 7 and 8 round spermatids.…”

“…Subsequent studies demonstrated that vitamin A deficiency in rats induces a progressive loss of differentiating germ cells, ultimately yielding seminiferous tubules containing only Sertoli cells and pre-meiotic germ cells (Mitranond et al, 1979;Sobhon et al, 1979;Huang et al, 1988;Morales and Cavicchia, 2002), and administration of vitamin A to vitamin A-deficient rats resumes spermatogenesis (van Pelt and de Rooij, 1990bRooij, , 1991. The deficient state that impaired spermatogenesis in mice was also produced by a vitamin A-deficient diet (van Pelt and de Rooij, 1990a;Sugimoto et al, 2012;Boucheron-Houston et al, 2013;Ikami et al, 2015), in a manner similar to that in rats, as described above.…”

Transport of vitamin A across blood‐tissue barriers is facilitated by STRA6

“…Other studies investigating the consequences of VAD in the testes also found that spermatogenesis is dependent on vitamin A availability. Of note, effect of dietary vitamin A deprivation did manifest at a much later time point in the previous study (42). Thus, STRA6 seems to provide a fail-safe mechanism to protect spermatogenesis and ensure the production of progeny even when vitamin A is in short supply.…”

Control of Germline Stem Cell Lineages by Diet and Physiology

“…For example, diet-induced obesity and vitamin D or zinc deficiency can lead to a decrease in male fertility in mice (Fan et al 2015; Sun et al 2015; Croxford et al 2011). Adult mice deprived of dietary vitamin A show testicular degeneration as a result of increased apoptosis and sloughing of immature germ cells into the lumen in more severe cases (Boucheron-Houston et al 2013). Several of these observations have parallels in humans: obese men are more likely to be infertile (Campbell et al 2015), and there is a positive correlation between vitamin D and zinc and sperm quality in adult men (Blomberg Jensen 2014; Colagar et al 2009).…”