Study On Human Sperm Mitochondrial DNA Deletion And Sperm Motility

Objective: Comparing mitochondrial DNA(mtDNA) 4977 base pairs(bp) common deletion in different groups(asthenospermia, oligoasthenospermia, oligospermia and samples with normal semen parameters) and discusses the influence of sperm mtDNA 4977 deletion on sperm motility and male fertility.Mehtods: A total of 902 semen samples of infertile and fertile males from the Assisted Reproduction Center of Jiangxi Maternal and Child Health Hospital were collected from February to July 2014. After analysed by CASA, the samples were assigned to four groups. asthenospermia froup: progressive motility rate<32%, sperm density >15×106/ml; oligospermia group: progressive motility rate>32%, sperm density <15×106/ml; oligoasthenospermia group: progressive motility rate<32%, sperm density<15×106/ml; nomal semen parameters group: progressive motility rate>32%, sperm density >15×106/ml. DNAs were extracted from the semen of these samples and were subject to PCR reaction, the following PCR products were examined on 2% agarose gels with gel electrophoresis, and the acquired PCR products were purified and analyzed by direct sequencing to confirm the acquired PCR products were mtDNA 4977 deletion.Results: There are 10 out of 345 cases with nomal semen parameters, 24 out of 278 asthenospermias, 33 cases of 200 cases of oligoasthenospermia and 2 out of 79 oligospermias were detected to harbor the mtDNA 4977 bp deletion, the rate is 2.9%, 8.63%, 16.5% and 2.53%. Comparison of the rate of mtDNA 4977 bp deletion among the groups: group asthenospermia and group oligoasthenospermia were both higher than group nomal semen parameters, the difference was statistically significant(P<0.05). There was no difference between group oligospermia and group nomal semen parameters.Conclusion: The mt DNA 4977 bp deletion rate in asthenospermia oligoasthenospermia groups were both higher than nomal semen parameters group, and the difference was statistically significant(P<0.05). Our results indicated that mtDNA 4977 bp deletion might be associated with and thus might also promote the pathogenesis of sperm motility.