自体全厚皮片移植后表皮—黑色素单位超微结构动态变化

Kinetic changes of ultrastructure of epidermal melanin unit in the full-thickness skin autograft

目的 探讨自体全厚皮片移植后色素沉着的成因。方法 应用超微结构细胞化学技术观察自体全厚皮片移植后表皮—黑色素单位 (EpidermalMelaninUnit,EMU)的超微结构动态变化 ,并借助电子计算机辅助图像分析技术 ,对黑色素细胞及角朊细胞内的黑色素小体形态学及分布形式进行分析。结果 术后 48h内表皮黑色素单位处于崩解状态 ;术后 72h后 ,表皮黑色素细胞 (Mel anocyte ,MC)及角朊细胞 (Kerationcyte,KC)功能及协同作用逐渐恢复并超过术前水平 ;1个月后 ,KC内 ,尤其是棘层及颗粒层KC内出现大量、呈单个分布的MS。结论 EMU内KC MC协同功能增强及从基底层到颗粒层的KC内出现大量大体积、呈单个形式分布的MS 。

Objective To study the ultrastructural mechanism causing hyperpigmentation of full thickness skin autograft. Methods\ The ultrastructural cytochemical technique was used to observe the kinetic changes of the ultrastructure of epidermal melanin unit (EMU) in the full thickness skin autograft. A computer assisted image analysis system was applied for analysis of the morphometry and distribution pattern of melanosomes in melanocytes and keratinocytes. Results ① In 48 hours postoperatively, the melanocytes and keratinocytes were seriously damaged in both function and structure. ② The structure and function of the melanocytes and keratinocyte began to restore at postoperative 72 hour and continued in a duration of 3 weeks. But coordination between the melanocytes and keratinocytes was relatively poor, accompanied with accumulation of melanosomes in the melanocytes and their extracellular space. ③ One month after surgery, a lager number of single, large melanosomes appeared in the keratinocytes through almost all of strata of epidermis due to acceleration in the formation of melanosome and transfer between melanocytes and keratinocytes, and enhanced by disturbance of degradation of melanosome in the keratinocytes. ④ There was no change in the state of keratinocytes and melanosomes in them, although the function of the melanocytes was decreased at 2 month after surgery. Conclusion\ The direct causes for the graft hyperpigmentation is that a large number of large, single dispersed melanosomes occurred in the keratinocytes through almost all of strata of the epidermis due to enhanced coordination between the melanocytes and keratinocytes.