Abstract
Objective
Mitochondria are factories for energy production and genetic alterations in mtDNA will directly impact OXPHOS function. The copy number of mtDNA (i.e., the number of mtDNA per spermatozoon) is one of the major mitochondrial genetic features. Besides mtDNA copy number, the change of either mtDNA or nDNA integrity is another important factor causing asthenospermia, or poor sperm motility in infertile men. In this study, we investigated the mtDNA copy number and the integrities of mtDNA and nDNA respectively in semen samples from different donors at 5,300 m altitudes.
Methods
Total DNA was extracted from semen samples from donors in two different altitudes. Quantitative PCR was performed to evaluate the mtDNA copy number. PCR amplification was used to examine the integrity of sperm mtDNA. Flow cytometry was carried out to investigate sperm nDNA integrity. All data were analyzed to show the statistical significance.
Results
Sperm mtDNA copy number for those living at high altitude (5,300 m) for one month was significantly higher (P < 0.05) than for those at the lower altitude (1,400 m) or in donors who had been living at the 5,300 m altitude for 1 year. In addition, sperm mtDNA copy numbers were remarkably decreased (P < 0.05) in those who had lived at the greater altitude for 1 year compared to those who had lived there for one month. The ratio of nDNA integrity among the 10,000 sperms at high altitude for one month was significantly lower (P < 0.05) than that at the lower altitude (1,400 m) or at 5,300 m for 1 year, and the ratio of nDNA integrity sperms at high altitude for 1 year was increased, and higher than that for at the lower altitude (P < 0.05).
Conclusion
High altitude can alter the mtDNA copy number and nDNA integrity in the sperms.
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Acknowledgments
This work was supported by the 973 Project of China (No. 2006CB504101), National Key Technology R & D Program of China (No.2009BAI85B01) and the National Natural Science Foundation of China (No. 30900715).
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The authors stated that there are no conflicts of interest regarding the publication of this article or financial ties to disclose.
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High altitude can alter the mtDNA copy number and nDNA integrity in the sperms.
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Supplemental figure 1
The graph of qPCR amplification. A: The standard linear curve of qPCR amplification; B: Melting curve analysis of qPCR product (JPEG 63 kb)
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Luo, Y., Liao, W., Chen, Y. et al. Altitude can alter the mtDNA copy number and nDNA integrity in sperm. J Assist Reprod Genet 28, 951–956 (2011). https://doi.org/10.1007/s10815-011-9620-y
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DOI: https://doi.org/10.1007/s10815-011-9620-y