title: Hepatitis B virus s protein enhances sperm apoptosis and reduces sperm fertilizing capacity in vitro.
abstract: OBJECTIVE
  Studying the impact of Hepatitis B virus S protein (HBs) on early apoptotic events in human spermatozoa and sperm fertilizing capacity.
  
  
  RESULTS
  Spermatozoa were exposed to HBs (0, 25, 50, 100 µg/ml) for 3 h, and then fluo-4 AM calcium assay, Calcein/Co(2+) assay, protein extraction and ELISA, ADP/ATP ratio assay, sperm motility and hyperactivation and sperm-zona pellucida (ZP) binding and ZP-induced acrosome reaction (ZPIAR) tests were performed. The results showed that in the spermatozoa, with increasing concentration of HBs, (1) average cytosolic free Ca(2+) concentration ([Ca(2+)]i) rose; (2) fluorescence intensity of Cal-AM declined; (3) average levels of cytochrome c decreased in mitochondrial fraction and increased in cytosolic fraction; (4) ADP/ATP ratios rose; (5) average rates of total motility and mean hyperactivation declined; (6) average rate of ZPIAR declined. In the above groups the effects of HBs exhibited dose dependency. However, there was no significant difference in the number of sperms bound to ZP between the control and all test groups.
  
  
  CONCLUSIONS
  HBs could induce early events in the apoptotic cascade in human spermatozoa, such as elevation of [Ca(2+)]i, opening of mitochondrial permeability transition pore (MPTP), release of cytochrome c (cyt c) and increase of ADP/ATP ratio, but exerted a negative impact on sperm fertilizing capacity.
authors.affiliation: Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Research Center for Reproductive Medicine, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Jihua
authors.initials: J
authors.lastname: Huang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhong
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Fang
authors.forename: Qingdong
authors.initials: Q
authors.lastname: Xie
authors.forename: Xiangjin
authors.initials: X
authors.lastname: Kang
authors.forename: Riran
authors.initials: R
authors.lastname: Wu
authors.forename: Fangzheng
authors.initials: F
authors.lastname: Li
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Xu
authors.forename: Hui
authors.initials: H
authors.lastname: Lu
authors.forename: Lan
authors.initials: L
authors.lastname: Xu
authors.forename: Tianhua
authors.initials: T
authors.lastname: Huang
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006515:Hepatitis B virus / Q000378:metabolism*; D006801:Humans; D007248:Infertility, Male / Q000378:metabolism / Q000821:virology; D008297:Male; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism* / Q000821:virology; D014764:Viral Proteins / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism
chemical_list: D014764:Viral Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D002118:Calcium