Chronic stress induces fur color change from dark to brown by decreasing follicle melanocytes and tyrosinase activity in female C57BL/6 mice / 生理学报

Increasing evidence suggests that stress may induce changes in hair color, with the underlying mechanism incompletely understood. In this study, female C57BL/6 mice subjected to electric foot shock combined with restraint stress were used to build chronic stress mouse model. The melanin contents and tyrosinase activity were measured in mouse skin and B16F10 melanoma cells. The enzyme-linked immunosorbent assay (ELISA) was used to determine the content of tumor necrosis factor α (TNF-α), interleukin- 1β (IL-1β) and interleukin-6 (IL-6) in the mouse skin. The content of nuclear factor κB (NFκB)/p65 subunit in mouse skins was valued by immunofluorescence staining. The results demonstrated that under chronic stress, the fur color turned from dark to brown in C57BL/6 mice due to the decrease of follicle melanocytes and tyrosinase activity in C57BL/6 mouse skin. Simultaneously, inflammatory responses in skins were detected as shown by increased NFκB activity and TNF-α expression in stressed mouse skin. In cultured B16F10 melanoma cells, TNF-α reduced the melanogenesis and tyrosinase activity in a dose-dependent manner. These findings indicate that chronic stress induces fur color change by decreasing follicle melanocytes and tyrosinase activity in female C57BL/6 mice, and TNF-α may play an important role in stress-induced hair color change.

Epidemiological character of retina white without pressure in healthy adolescents in the air force cadets' medical selection / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the epidemiological character of white without pressure(WWOP)in the healthy adolescents by fundus examination and provide theoretical support for air force recruitment and health examination. <p>METHODS:A total of 461 middle school graduates and 71 junior middle school graduates, who participate in the air force cadets' medical selection, were selected as subjects. The ultra-wide-angle laser fundus scanning system, direct ophthalmoscopy and three-sided mirror were used to check the fundus. The χ² test was used to analyze the incidence and distribution of fundus abnormalities.<p>RESULTS: The prevalence of WWOP in healthy adolescents was as high as 2.63%. There was no significant difference in the prevalence of WWOP among junior middle school graduates(<i>P</i>>0.05). The lesion was more common in the temporal quadrant, especially the lower temporal quadrant. In the eyes with WWOP in high school graduates, the proportion of retinal degeneration was as high as 18.18%, which was significantly higher than that without WWOP. <p>CONCLUSION:WWOP is not uncommon in adolescents and is more common in the temporal quadrant. The proportion of retinal degeneration in eyes with WWOP is significantly higher. Thus, in order to avoid missed diagnosis, the surrounding retina should be carefully examined if WWOP was founded in aviation physical examination.