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Asian Journal of Andrology (2010) 12: 247-256. doi: 10.1038/aja.2009.78; published online 14 December 2009.
The protective effects of α-ketoacids against oxidative stress on rat spermatozoa in vitro
Shi-Feng Li1,*, Hai-Xiong Liu1,*, Yun-Bin Zhang1, Yuan-Chang Yan1 and Yi-Ping Li1
1 Laboratory of Molecular Cell Biology, Shanghai Key Laboratory for Molecular Andrology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
Correspondence: Prof. Yi-Ping Li, Laboratory of Molecular Cell Biology, Shanghai Key Laboratory for Molecular Andrology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China. Fax: +86-21-5492-1415 E-mail: Yipingli@sibs.ac.cn
* These two authors contributed equally to this work
Received 5 May 2009; Revised 2 August 2009; Accepted 3 November 2009; Published online 14 December 2009.
| Abstract |
The aim of this study was to determine the effects of antioxidants, including α-ketoacids (α-ketoglutarate and pyruvate), lactate and glutamate/malate combination, against oxidative stress on rat spermatozoa. Our results showed that H2O2 (250 μmol L−1)-induced damages, such as impaired motility, adenosine triphosphate (ATP) depletion, inhibition of sperm protein phosphorylation, reduced acrosome reaction and decreased viability, could be significantly prevented by incubation of the spermatozoa with α-ketoglutarate (4 mmol L−1) or pyruvate (4 mmol L−1). Without exogenous H2O2 in the medium, the addition of pyruvate (4 mmol L−1) significantly increased the superoxide anion (O2−·) level in sperm suspension (P ≤ 0.01), whereas the addition of α-ketoglutarate (4 mmol L−1) and lactate (4 mmol L−1) significantly enhanced tyrosine-phosphorylated proteins with the size of 95 kDa (P ≤ 0.04). At the same time, α-ketoglutarate, pyruvate, lactate, glutamate and malate supplemented in media can be used as important energy sources and supply ATP for sperm motility. In conclusion, the present results show that α-ketoacids could be effective antioxidants for protecting rat spermatozoa from H2O2 attack and could be effective components to improve the antioxidant capacity of Biggers, Whitten and Whittingham media.
Keywords: α-ketoacids; antioxidants; oxidative stress; reactive oxygen species |
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