Association between asthenospermia and mtDNA mutations in ND3 and ND4L genes / 中国病理生理杂志

ABSTRACT

AIM: To explore the molecular mechanism of asthenospermia(AST) by preliminary screening of nucleotide sequences from the ND3 and ND4L genes of mitochondrial DNA(mtDNA). METHODS: Samples from 50 AST patients and 42 age-matched normal controls were collected according to the WHO criteria. Density gradient centrifugation was applied to separate spermatozoa with different vigor. The ND3 and ND4L genes of mtDNA were amplified and sequenced directly from the extracted genomic DNA from AST patients and normal controls. The sequences were compared with revised Cambridge Reference Sequence(rCRS) to analyze the variants. RESULTS: A total of 22 nucleotide variations were found in ND3 and ND4L genes of mtDNA in asthenospermia group and control group. G10320A, A10398G and T10609C were missense mutations, while A10157G and A10313C were the reported for the first time in this study. Haplotype N in patients with AST(33/50) was higher than that in control group(14/42, P<0.05), and haplotype R9 in patients with AST(15/50) was also higher than that in control group(4/42, P<0.05) through genetic testing of ND3 gene. Rates of sperm progressive motility of haplotype F1, F2 and R9 were significantly lower than those of haplotype M and M rest. Two haplotype differences, haplotype M and N, were found in the same AST patient's spermatozoas which had different vigor. Haplotype M had stronger vigor, while haplotype N had lower vigor. By sequencing ND3 gene of mtDNA from 50 AST patients, we detected G10310A heteroplasmic mutation in 2 specimens of asthenospermia with poor and moderate motility spermatozoa, respectively. No mutation occurred in good motility spermatozoa. CONCLUSION: Haplotype of mitochondrial may have some correlation with sperm motility. The nt10398G-10400T polymorphisms may have benefit for sperm motility, whereas the mutation in nt10310A may impair sperm motility.