Molecular and structural changes related to hepatitis E virus antigen and its expression in testis inducing apoptosis in Mongolian gerbil model

Hepatitis E virus (HEV) infection has been associated with a wide range of extrahepatic manifestations, so this study was designed to examine the effect and role of HEV on structural and molecular changes in the testicular tissues of Mongolian gerbils experimentally infected with swine HEV. HEV RNA was first detected in testis at 14 days post--inoculation and reached a peak between 28 and 42 days later with viral load between 3.12 and 6.23 logs/g by PCR assays. Changes including vacuolation, sloughing of germ cells, formation of multinuclear giant cells, degeneration, necrosis of tubules and damaged blood--testis barrier were observed through transmission electron microscopy. HEV ORF2 antigen was detected in the sperm cell cytoplasm along with decrease in relative protein of zonula occludens--1 through immunohistochemistry. HEV ORF3 antigen and ZO--1 protein were detectable by Western blotting. Lower (P<.05) serum testosterone and higher (P<.05) blood urea nitrogen level was observed in inoculated Mongolian gerbils. Likewise, increased (P<.05) germ cell apoptosis rate was detected with significant increased expression of Fas-L and Fas in HEV-inoculated groups at each time points. Up-regulation (P<.05 or P<.01) in mRNA level of Fas-L, Fas, Bax, Bcl-2 and caspase-3 was observed in HEV RNA-positive testes. Our study demonstrated that after experimental inoculation, HEV can be detected in testis tissues and viral proteins produce structural and molecular changes that in turn disrupt the blood--testis barrier and induce germ cell apoptosis.