infection. These events were 518303-20-3 custom synthesis probably caused by the imbalance between ROS production and TAC induced by HBs, leading to the accumulation of the unrepaired DNA damage and formation of sperm chromosome aberrations. Taken together, our data provided the solid evidence that HBs exposure could cause a series of 11885967” deleterious events in sperm cells such as induction of ROS generation and lipid peroxidation, reduction of total antioxidant capacity, PS externalization, activation of caspases, and DNA fragmentation, resulting in increased apoptosis of sperm cells, the loss of sperm membrane integrity and sperm dysfunctions. Effects of HBs on Sperm Functions Materials and Methods Ethical approval After the informed consent approval was obtained, the human sperm samples were collected from the healthy male donors who were explicitly informed about the research aims, their rights and interests in the research. All the protocols used in the present study were approved by Institutional Ethical Review Board of Shantou University Medical College, and conformed to the ethical guidelines of the 2008 Declaration of Helsinki as reflected in a prior approval by the institution’s human research committee. was separated, then the absorbance was measured at 530 nm and expressed as units per 16106/ml sperm cells for MDA. The above experiment was repeated five times. Assessment of antioxidant status in sperm cells FRAP assay was performed to measure the TAC of sperm cells in the test and control groups using a commercially available assay kit in a Multimode Microplate Reader according to the manufacturer’s instructions. Briefly, the sperm cells were homogenized in 200 ml of phosphate buffer and sonicated over ice, and 
then centrifuged at 12,0006g at 4uC for 5 min to collect the supernatant for assay of TAC. The values were calculated using optical density at 593 nm and expressed as units per 16106/ml sperm cells for TAC. The above experiment was repeated five times. Preparations of human spermatozoa Human sperm samples were obtained by masturbation after 3 days of sexual abstinence from the healthy men. Semen samples were kept in a CO2 incubator for 30 min to allow liquefaction. Motile spermatozoa were selected by the swim-up method as follows: in each test tube, the 0.5 ml liquefied semen sample layered gently under 2 ml of biggers-whittem-whittingham medium containing 0.3% bovine serum albumin and incubated at 37uC in a 5% CO2 incubator for 1 h. The supernatant collected from tubes was centrifuged at 3006g for 5 min, and the pellet of motile sperm was washed once. The final concentration of spermatozoa was roughly adjusted to 16106 sperm/ml in BWW medium with 0.3% BSA for the following use. Evaluation of PS externalization in sperm cells The annexin-VFITC Apoptosis Detection Kit was used to detect PS translocation from the inner to the outer leaflet of the sperm plasma membrane. The assay was carried out according to the instructions of the manufacturer. Briefly, for each assay, 16106/ml washed sperm cells in the test and control groups were gently resuspended in 0.5 ml cold PBS followed by incubating with annexin V-FITC and PI at room temperature in the dark for 15 min. To prepare the samples for flow cytometry, sperm cells were washed twice with annexin binding buffer. For statistical analysis, the cell population was considered positive for PS externalisation. The above experiment was repeated five times. The exposure of sperm cells to HBs The sperm cells were
