OBJECTIVETo explore the action mechanisms of temperature in male infertility or subfertility by observing the effects of different temperatures on the proliferation of and occludin (OCLN) expression in rat Sertoli cells in vitro.

METHODSWe isolated Sertoli cells from the testis of male Wistar rats, and performed oil red O staining and immunohistochemistry to identify their FasL. We cultured the Sertoli cells at 34 degrees C (control group) and at 35, 36, 37, 38 and 39 degrees C (experimental groups) for 4 days. Then we measured their proliferation by CCK-8 assay, observed their morphology and structure by hematoxylin-eosin staining, and determined their OCLN expression level by Western blotting and immunofluorescence.

RESULTSThe purity of the isolated Sertoli cells was (96.20 +/- 1.95)%. CCK-8 assay indicated that the proliferation of the Sertoli cells was increased between 34 and 36 degrees C, and decreased at 36-39 degrees C. The pyknotic nuclei and fragmentation of the Sertoli cells were more obvious at > 36 degrees C. Western blot and immunofluorescence showed the highest level of OCLN expression at 36 degrees C, which, however, decreased while the temperature rose above 36 degrees C (P < 0. 01).

CONCLUSIONHigh temperature (> 36 degrees C) inhibited the proliferation of rat Sertoli cells in vitro, and decreased the expression of OCLN, which suggests that a higher temperature above 36 degrees C may reduce male fertility by affecting the proliferation of Sertoli cells and integrity of the tight junction among Sertoli cells or Sertoli cells and other cells.