title: Scrotal heat stress causes sperm chromatin damage and cysteinyl aspartate-spicific proteinases 3 changes in fertile men.
abstract: OBJECTIVE
  To observe changes in semen parameters, sperm DNA integrity, chromatin condensation and cysteinyl aspartate-spicific proteinases (Caspase-3) in adult healthy men after scrotal heat stress (SHS).
  
  
  METHODS
  The scrotums of 19 healthy male volunteers were exposed to the condition of 40-43 °C SHS belt warming 40 min each day for successive 2 days per week. The course of SHS was continuously 3 months. Routine semen analysis, hypo-osmotic swelling (HOS) test, eosin Y (EY) staining sperm HOS and chromatin dispersion (HOS/SCD) test, HOS and aniline blue (HOS/AB) staining test were carried out before, during and after SHS. The activated Caspase 3 levels of spermatozoa were determined with a microtiter plate reader.
  
  
  RESULTS
  The mean parameters of sperm concentration, motility and normal morphological sperm were significantly decreased in groups with sperm being collected during SHS 1, 2 and 3 months when compared with those in groups of pre-SHS (P < 0.01). Statistically significant differences of sperm DNA fragmentation, normal sperm membrane and vitality, and Caspase-3 activity were observed between the groups of before SHS and after SHS 3 months and the groups of during SHS 1, 2 and 3 months (P < 0.001). Three months the SHS stopped, various parameters recovered to the level before SHS. Abnormal sperm with HOS/AB and HOS/SCD showed a negatively significant correlation with normal sperm by HOS/EY test, and WBC in semen showed a positively significant correlation with Caspase-3 activity. The percentage of abnormal sperm by using the test of HOS/SCD showed a positively significant correlation with that of HOS/AB.
  
  
  CONCLUSIONS
  The continuously constant SHS can impact the semen quality, sperm DNA integrity, chromatin condensation and Caspase-3, and the combination of HOS plus AB test may simultaneously determine the integrity of membrane and chromatin condensation at the same spermatozoon.
authors.affiliation: Key Laboratory of Birth Regulation and Control Technology of National Health and Family Planning Commission of China, Key Laboratory for Improving Birth Outcome Technique, Shandong Provincial Family Planning Institute of Science and Technology, 69 Yuhan Road Jinan, Shandong, 250002, People's Republic of China.
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Zhang
authors.forename: Zhi-Da
authors.initials: ZD
authors.lastname: Shi
authors.forename: Jian-Chun
authors.initials: JC
authors.lastname: Yu
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Zhang
authors.forename: Lei-Guang
authors.initials: LG
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Qiu
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism*; D002843:Chromatin / Q000235:genetics / Q000473:pathology*; D004249:DNA Damage; D018882:Heat Stress Disorders / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007248:Infertility, Male / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D008297:Male; D011379:Prognosis; D012611:Scrotum / Q000201:enzymology / Q000473:pathology*; D055101:Semen Analysis; D013094:Spermatozoa / Q000201:enzymology / Q000473:pathology*
chemical_list: D002843:Chromatin; D053148:Caspase 3