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| MicroRNAs (miRNAs) are believed to play important roles in developmental and other cellular processes by hybridizing to complementary target mRNA transcripts, also involved in the development of mammalian spermatogenesis. Fluoride and sulfur dioxide are two well known environment pollutants, which present a serious threat to male reproduction. To compare the global miRNA expression profiling and regulation pattern in mouse testes between normal mouse and F or SO2-treat mice by using miRNA microarray technology, 144 male Kunming mice were divided randomly into four groups of thirty-six mice each. One group was left untreated as controls, and the other three groups were administered, respectively, for thirteen consecutive weeks, 150 mg NaF/L (45 mg F-/L) in their drinking water, SO2 in ambient air (26.2 mg/m3 SO2, 3hr/day), or were exposed to both NaF and SO2 together. After 15 weeks, testis totals RNA of the mouse model were gathered for miRNA microarray study. Simultaneity, reproductive capacity of mice, DNA contents distribution in testis cells, and bcl-2, bax, and p53 genes mRNA expression were detected to interpret the changed miRNA expression profiles. The results exhibited that MiR-106a in the NaF group, miR-449a, miR-16, miR-15b, and miR-34c in the SO2 groups, and miR-204 and miR-34a in the NaF+SO2 group were un-regulated significantly in testes of mice, compared with the controls, respectively. Whereas miR-34a decreased by 3.3-fold in the SO2 group, and miR-34b was down-regulated by more than 1.5-fold in the NaF+SO2 group. Further investigation indicates that predicted pathways according to significant miRNA are primary related to cell cycle, apoptosis, and MAPK signal pathway. Furthermore, the development of testis and reproductive capacity of male mouse have been weakened by F or SO2, especially, by F and SO2 together treatment. FCM analysis show that the percents of apoptosis cells in testis were increased significantly in experiment groups, DNA contents distributions have been disturbed by F or SO2. Expression of p53 and bcl-2 mRNA decreased, and bax gene was increased by1.87, 2.40 and 2.89 times as high as those in the control groups by QRT-PCR. However, both F or SO2 and the combination heighten the ratios of p53/bcl-2 and bax/bcl-2, all these changes lead to a common result of the spermatogenic cell apoptosis. In conclusion, changed miRNAs expression regulation should be look as the main mechanism of depressed male reproduction function of mouse induced by F or SO2 or their combination. This is the first miRNA microarray study to focus on evaluating altered miRNA expression profiles in testis of mice exposure to F or SO2. The miRNA microarray and bioinformatics analysis is a fast, high-throughout, exacts, foreground technique contribute toward elucidating the function of miRNAs in normal and impaired male reproduction by environment factors. |
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| Keywords:Fluoride and sulfur dioxide; Male mice; miRNAs expression profile; Testis |
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