title: [Expression of Chk1 in human sperm and its significance].
abstract: OBJECTIVE
  To investigate the expression of the Chk1 gene in human sperm and its clinical significance.
  
  
  METHODS
  We collected 80 semen samples and divided them into 4 groups of equal number: normal, oligospermia, asthenozoospermia and oligoasthenozoospermia. The Chk1 expression and its relative level were detected by Western blot and RT-PCR, sperm DNA damage and gradient changes assessed by DNA ladder analysis, and sperm apoptosis determined by Annexin V/PI double staining in each group.
  
  
  RESULTS
  The Chk1 gene was expressed in all the four groups, but with significant differences (P < 0.01); the relative levels of CHK1 protein were similar to those of Chk1 mRNA in the normal, oligospermia, asthenozoospermia and oligoasthenozoospermia groups, which were 1.00 +/- 0.22, 0.76 +/- 0.10, 0.45 +/- 0.08 and 0.37 +/- 0.07, respectively. DNA ladder analysis showed a marked DNA ladder in the asthenozoospermia and oligoasthenozoospermia groups. Sperm apoptosis was markedly increased in the oligospermia, asthenozoospermia, oligoasthenozoospermia and 100% graded sperm groups ([ 8.3 +/- 0.60]%, [11.6 +/- 0.92]%, [12.5 +/- 1.43]% and [17.0 +/- 1.98]%), as compared with the normal group ([7.6 +/- 0.34]%) (P < 0.05).
  
  
  CONCLUSIONS
  Chk1 is expressed in human sperm, but differently in different semen quality groups. And its expression is correlated with sperm DNA damage and apoptosis; its reduction may lead to declined sperm repair and increased sperm apoptosis and thus affect semen quality.
authors.affiliation: Department of Urology, The Third Hospital of Peking University, Beijing 100191, China. liudefeng2007@yahoo.com.cn
authors.forename: De-feng
authors.initials: DF
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Lu-lin
authors.initials: LL
authors.lastname: Ma
authors.forename: Kai
authors.initials: K
authors.lastname: Hong
authors.forename: Lian-ming
authors.initials: LM
authors.lastname: Zhao
authors.forename: Ren-pei
authors.initials: RP
authors.lastname: Yuan
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.forename: Jian-ming
authors.initials: JM
authors.lastname: Liu
authors.forename: Chong
authors.initials: C
authors.lastname: Li
mesh_terms: D017209:Apoptosis; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D006801:Humans; D008297:Male; D011494:Protein Kinases / Q000235:genetics*; D055101:Semen Analysis; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1