| Objective Vetical transmission of HBV represents a new but unconfirmed mode of transmission which is characterized by transfer of HBV DNA to the embryo via germ cells, thus making the offspring being carriers or in a sick state. The key of researches in paternal-fetal vertical transmission lies in the mechanism of HBV passing BTB. By transfecting the rat testes with HBV DNA in different groups, the present study aim to changes in the integrity and physiological function of blood-testis barrier (BTB) after consumption of alcohol in large amount. Also discussed was the effectiveness of BTB in keeping HBV DNA contained plasmid from transfecting epithelial cells of seminiferous tubules. Furthermore, factors and mechanisms influencing the integrity of BTB were reviewed.Methods Totally, twenty mature male wistar rats were randomly divided into experimental group (group A, n=10) and control group (group B, n=10). All of the ten rats in group A were treated with 1 ml 50% alcohol per 100 g body weight per day by intragastric administration for 40 days successively. Rats in group B were treated with 1 ml normal saline per 100 g body weight per day by intragastric administration for 40 days successively. HBV DNA containing plasmid was delivered into the testes and polymerase chain reaction (PCR), Real-time quantitative PCR (Real-time PCR), in situ hybridization (ISH) and transmission electron microscopy (TEM) were employed to investigate the transfecting profile.Results Electrophoregram showed a specific positive band of HBV DNA in group A. Real-time PCR found the mean content of DNA in group A was higher than that in group B, and the difference was statistically significant. Positive hybridization signal in group A was dispersed and distributed widely in spermatogenic cells in the inner and outer compartment of seminaferous epithelium. TEM examination for group A found loose, thickened, wrinkled and broken basement with varying thickness membrane in seminiferous tubules, vacuolisation in the interspace between spermatogenic cells, sustentacular cells and basement membrane of seminiferous tubules, and enlarged interspace between seminiferous tubules, seminaferous epithelium, spermatogenic cells, sustentacular cells and neighbour cells was also observed.Conclusion The integrity of BTB can be compromised by alcohol consumption. Damage of BTB and structure anomaly of seminiferous tubules can render all the seminaferous epithelium susceptible to HBV DNA infection, increasing the transfecting rate. BTB is one of the main functions of sustentacular cells. BTB protects spermatogenic cells which are in a differentiated state and prevents autoimmunity. Also it regulates the division and differentiation of spermatogenic cells and confers a favorable microenvironment for the genesis, maturation and release of sperm in the convoluted tubule. To be protective, BTB has to maintain its integrity, which can be compromised by alcohol, rendering all the spermatogenic cells susceptible to HBV infection. |
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