Heat stress response of male germ cells

Abstract

The vast majority of mammalian testes are located outside the body cavity for proper thermoregulation. Heat has an adverse effect on mammalian spermatogenesis and eventually leads to sub- or infertility. Recent studies have provided insights into the molecular response of male germ cells to high temperatures. Here, we review the effects of heat on male germ cells and discuss the mechanisms underlying germ cell loss and impairment. We also discuss the role of translational control in male germ cells as a potential protective mechanism against heat-induced germ cell apoptosis.

Fig. 1

Formation of stress granules (SGs) in male germ cells. Adult mouse testes of control (Normal) and heated at 42 °C for 20 min (Heat) were costained for two robust markers of SGs, DAZL (green) and eIF3 (red). DNA was stained with DAPI (blue). The images were taken from the seminiferous epithelial stage IV. Arrowheads indicate SGs. Note that SGs were predominantly formed in pachytene spermatocytes. Spc spermatocyte; RSpd round spermatid; ESpd elongated spermatid. Scale bar 10 μm

Fig. 2

Model for heat stress response in male germ cells. Heat stress affects germ cells as well as somatic cells, leading to disruption of normal spermatogenesis. The cellular responses differ between different types of germ cells. Spc spermatocytes; SG stress granule