小鼠皮肤切创愈合过程中caspase-9、-3表达的研究

A study on the expression of caspase-9 and caspase-3 during the skin incised wound healing in mice

目的研究caspase-9、-3在小鼠皮肤切创愈合过程中的表达及其变化规律。方法在小鼠背部正中制作皮肤全层切创模型,应用免疫组化染色技术观察切创及切创周边区内caspase-9、-3的表达情况,以无切创的小鼠皮肤作为对照。结果对照组中caspase-9、-3表达于表皮层,毛囊及皮脂腺。伤后3h损伤区及损伤周边区中可见少量多核粒细胞表达caspase-9、-3,6~24h,部分浸润的多核粒细胞和单核细胞caspase-9、-3阳性,此后caspase-9、-3阳性细胞逐渐以单核细胞和成纤维细胞为主。伤后caspase-9、-3阳性细胞率逐渐升高并在3d达到高峰,此后逐渐下降,至14d最低。结论caspase-9、-3可能引发正常小鼠皮肤表皮、毛囊和皮脂腺细胞的凋亡并参与正常皮肤细胞的自我更新;在小鼠皮肤切创愈合过程中,caspase-9、-3在多核粒细胞、单核细胞及成纤维细胞中表达,其时序性变化规律可望用于皮肤切创损伤时间的判定。

Objective To investigate the time-dependent expressions of caspase-9 and caspase-3 during skin incised wound healing in mice and their applicabilities to estimation of wound age. Methods An incised wound was made in the mouse dorsal skin. By S-P methods, the expressions of caspase-9 and caspase-3 were studied in cutaneous incised wound as well as in normal skin in control mice. Results Caspase-9- and caspase-3-positive cells were detected in epidermis, hair follicles, and sebaceous glands in control skin. 3h after injury, caspase-9 or caspase-3 was observed in polymorphonuclear cells （PMNs） in the wound and peripheral region. From 6h to 24h post-wounding, caspase-9 and caspase-3 immunoreactivity was identified in part of infiltrating PMNs and mononuclear cells （MNCs）. Afterwards, the MNCs and fibroblastic cells （FBCs） accounted for the most part of the caspase-9- and caspase-3-positive cells. The percentage of caspase-9 or caspase-3 positive cells was low in the wound specimens aged from Oh to 3h, and maximized in parallel in the specimens aged 3 day, which decreased and minimized in the specimens aged 14 day. Conclusion The results suggest that caspase-9 and caspase-3 may be involved in the apoptosis of epidermis, hair follicle and sebaceous gland cells and take part inthe homeostasis of normal skin. Caspase-9and caspase-3 are expressed in PMNs, MNCs and FBCs during skin incised wound healing in mice and may be used as the markers for wound age determination.