The impact of long-term exposure to Space environment on adult mouse testis

The presence of 3- and 17 β HSD, the mRNA expression of FSH receptor (FSHR), LH receptor (LHR) and androgen receptor (AR), interleukin-1β (IL-1β) were evaluated, by quantitative RT-PCR, in the testis of mice (C57BL/10) under different gravity conditions (0 g: MDS, 91 days in International Space Station, ISS, and 1 g: ground control) either wild type or pleiotrophin transgenic (overexpressing osteoblast stimulating factor-1). Histological examination of the testes of the control groups revealed regularly configured seminiferous tubules. The testes from spaceflown animals show disorganization, sloughing of cells in the lumen, separation of germ cells from the basal laminae and vacuolation of the germinal epithelium. The interstitial tissue displayed inflammatory exudates. No great differences are observed between Wild (WT) and Transgenic (TG) mice. Immunihistochemistry for 3β-HSD and 17β-HSD shows similar localization in Leydig cells in all animals. Therefore the immunoreactions of ISS (WT and TG) decreases. HSP70 immunohistofluorescence was localized in the interstitial tissue in flown samples. Transcription of the studied genes was comparable in the ground controls, with slightly higher levels of mRNA transcripts in Transgenic mice with respect to WT. Microgravity did not affect expression of LHR in both samples, whereas an increase in FSHR was observed in WT. On the other hand, higher levels of mRNA transcripts for AR observed in flown testes (WT and TG). Moreover, a particularly high expression of IL-1β was observed in samples from ISS.