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Abstract Background: UVB irradiation can cause acute damage such as sunburn, or photoaging and melanoma, all of which are major health threats. Objective: This study was designed to investigate the mechanism of skin photoaging induced by UVB radiation in mice through the analysis of the differential expression of miRNAs. Methods: A UVB irradiation photoaging model was constructed. HE and Masson special stains were used to examine the modifications in the epidermis and dermis of mice. The miRNA expression profiles of the mouse skin model exposed to UVB radiation and the normal skin of mice were analyzed using miRNA-sequence analysis. GO and Pathway analysis were employed for the prediction of miRNA targets. Results: A total of 23 miRNAs were evaluated for significantly different expressions in comparison to normal skin. Among them, 7 miRNAs were up-regulated and 16 were down-regulated in the skin with photoaging of mice exposed to UVB irradiation. The differential expression of miRNA is related to a variety of signal transduction pathways, among which mmu-miR-195a-5p and mitogen-activated protein kinase (MAPK) signal pathways are crucial. There was a significant differential expression of miRNA in the skin of normal mice in comparison with the skin with photoaging induced by UVB irradiation. Study limitations: Due to time and energy constraints, the specific protein level verification, MAPK pathway exploration, and miR-195a-5p downstream molecular mechanism need to be further studied in the future. Conclusions: UVB-induced skin photoaging can be diagnosed and treated using miRNA.
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<p><b>OBJECTIVE</b>To investigate the differences in semen quality at different times of reanalysis and the correlation of sperm DNA fragmentation index (DFI) with sperm motility alteration using semen samples completely liquefied and normal in initial examination.</p><p><b>METHODS</b>We analyzed 127 semen samples up to the inclusion criteria with the computer-assisted semen analysis (CASA) system at 15, 30 and 60 min after semen collection, and obtained sperm morphology parameters and DFI by Shorr staining and acridine orange test (AOT) , respectively.</p><p><b>RESULTS</b>Sperm concentration, and the percentages of grades a and b sperm showed no statistically significant differences at the three time points (P > 0.05). The percentages of grades a + b and a + b + c sperm were significantly higher at 15 min than at 30 and 60 min after semen collection (P < 0.05), but with no significant difference between the latter two time points (P > 0.05). The incidence of alternation from normal to abnormal in at least one index of sperm motility at different times was 25.2%, but there were no significant differences in sperm DFI and morphology between the normal and abnormal groups (P > 0.05). Among the altered parameters of sperm motility from 15 to 60 min, the percentages of grades a, a + b and a + b + c sperm were all positively correlated with sperm DFI (P < 0.05).</p><p><b>CONCLUSION</b>Semen samples completely liquefied within 15 min after collection and normal in initial examination, when reanalyzed at 30 and 60 min, showed significant decreases in the percentages of grades a + b and a + b + c sperm, but not in the percentages of grades a and b sperm, and the parameters of sperm motility might be abnormal. Thus, at least 2 sperm analyses are required for a comprehensive evaluation of fertility. Significant difference between the results of the two analyses, and particularly a markedly reduced percentage of rapidly progressive sperm, might indicate sperm DNA damage, and thus the necessity of sperm DNA damage detection.</p>