OBJECTIVETo investigate the influence of temperature on the expressions of c-kit and PI3K in spermatogonia cultured in vitro at 32 degrees C and 37 degrees C, and provide basic scientific data for the mechanism of spermatogenic impairment due to body temperature (37 degrees C).

METHODSIsolated spermatogenic cells were cultured in vitro at 32 degrees C and 37 degrees C, and their adherence, proliferation and morphologic changes were observed and recorded under the inverted phase contrast microscope. At 8 days, the spermatogonia were separated by Percoll density gradient centrifugation and the differential adhesion method. The expressions of c-kit and PI3K mRNA and proteins in the separated cells were detected by real time polymerase chain reaction and Western blot, respectively. The c-kit gene was sequenced to identify the occurrence of mutations.

RESULTSAdherence, division and proliferation of the cells were observed in both the 32 degrees C and 37 degrees C groups. The expressions of c-kit and PI3K mRNA and proteins in the spermatogonia were significantly higher in the 32 degrees C group than in the 37 degrees C group (P < 0.05). The 32 degrees C group showed no mutation of c-kit in exon 9, 11 and 13; the 37 degrees C group exhibited no mutation in exon 11 and 13, but possible insertion or deletion mutations in exon 9.

CONCLUSIONCulturing in vitro at 37 degrees C could inhibit the expression of proliferation- and differentiation-related genes in spermatogenic cells and lead to the mutation of the c-kit gene.