Hepatocyte growth factor (HGF) regulates blood–testis barrier (BTB) in adult rats

We have studied the effects of HGF on BTB dynamics in adult rats. We demonstrate that, at stages VII–VIII of the epithelium wave when germ cells traverse the BTB, HGF reduces the levels of occludin and influences its distribution pattern and assembling. Moreover, we report that, at stages VII–VIII, HGF significantly increases the amount of active TGF-β and the amount of uPA present in the tubules. For the first time we report that, in the same stages, HGF reduces the amount of actin present in the BTB region, in which occludin levels are highest, and modifies the morphology of the actin cytoskeleton network. At the level of maximal intensity of occludin fluorescence, we report that HGF also modifies the colocalization of occludin and actin. Lastly, we demonstrate that HGF is maximally expressed at stages VII–VIII, whereas its levels fall in the subsequent stages.

► We have studied the effects of HGF on the regulation of the BTB in the adult rats.
► HGF in stages VII–VIII decreases levels, localization and assembling of occludin.
► HGF significantly increases the amount of the active fraction of TGF-β and uPA.
► HGF influences actin amount, position and morphology associated with tight junctions.
► HGF is maximally expressed in stages VII–VIII of the seminiferous epithelium cycle.