Interest in the role of male factor in infertility continues to mount with defects related to sperm movement considered as one of the more severe forms of subfertility. The peroxisome proliferator-activated receptor gamma (PPARγ) primarily regulates the expression of target genes involved in energy control as well as lipid and glucose metabolism. Although the pivotal roles of these receptors on female fertility have been reported, there are limited studies addressing PPARs role(s) in the male. This study was designed to determine and compare PPARα, PPARβ and PPARγ mRNA expression in sperm cells of normozoospermic and asthenozoospermic men. In addition, flow cytometric analyses, immunofluorescence and western blot were used to evaluate PPARγ protein levels in spermatozoa. We have compared the sperm PPARs mRNA relative expression in 27 normozoospermic and 28 asthenozoospermic samples and monitored sperm PPARγ protein levels in 39 normozoospermic and 40 asthenozoospermic samples using flow cytometry. We have also assessed in a sub-group of seven normozoospermic and eight asthenozoospermic samples, PPARγ protein levels by western blotting. Relative expression of PPARγ mRNA in normozoospermic men was found to be significantly higher (P = 0.004) than in asthenozoospermic men while PPARα and PPARβ relative expression was similar in the two groups. Likewise, PPARγ showed a positive correlation with motility (r = 0.34; P < 0.05), sperm concentration (r = 0.33) and the percentage of progressive motile spermatozoa (r = 0.31). In agreement with the mRNA behavior, sperm PPARγ protein levels as measured by flow cytometry (P = 0.066) and western blot (P = 0.089) showed a tendency to be higher in normozoospermic than asthenozoospermic men. The present study proposes a link between PPARγ gene expression level and motility in human sperm.

Abbreviations: PPARs: Peroxisome Proliferator-Activated Receptors; CASA: Computer Assisted Semen Analysis; TFA: Trans Fatty Acids; HTF: Human Tubal Fluid; PBS: Phosphate-Buffered Saline; PPP: Pentose Phosphate Pathway; PI3K: Phosphoinositide 3-Kinase; G6PDH: Glucose 6-Phosphate Dehydrogenase

人们对男性因素在不孕症中的作用的兴趣不断增加，其中与精子运动有关的缺陷被认为是最严重的不育症形式之一。过氧化物酶体增殖物激活受体γ（PPARγ）主要调节参与能量控制以及脂质和葡萄糖代谢的靶基因的表达。尽管已报道了这些受体对女性生育力的关键作用，但针对男性中PPAR的作用的研究还很有限。本研究旨在确定和比较PPARα，PPARβ和PPARγ正常精子和精弱精子男性精子中的mRNA表达。此外，流式细胞仪分析，免疫荧光和蛋白质印迹被用来评估精子中PPARγ蛋白水平。我们比较了27个正常精子和28个弱精子精子中精子PPARs mRNA的相对表达，并使用流式细胞仪监测了39个正常精子和40个精子精子中的精子PPARγ蛋白水平。我们还通过蛋白质印迹法在七个正常精子和八个精子精子样本的亚组中评估了PPARγ蛋白水平。发现正常精子症男性中PPARγmRNA的相对表达显着高于无精子症男性（P = 0.004），而PPARα和PPARβ两组的相对表达相似。同样，PPARγ与运动性（r = 0.34； P <0.05），精子浓度（r = 0.33）和进行性运动精子百分比（r = 0.31）呈正相关。与mRNA行为一致，通过流式细胞术（P = 0.066）和蛋白质印迹（P = 0.089）测量的精子PPARγ蛋白水平在正常精子中比在无精子症中更高。本研究提出了PPARγ基因表达水平与人类精子运动之间的联系。

缩写： PPAR：过氧化物酶体增殖物激活受体；CASA：计算机辅助精液分析；TFA：反式脂肪酸；HTF：人类输卵管液；PBS：磷酸盐缓冲盐水；PPP：磷酸戊糖途径；PI3K：磷酸肌醇3-激酶；G6PDH：葡萄糖6磷酸脱氢酶