默克尔细胞联合雪旺氏细胞移植在创面触觉恢复中的作用

After the skin and soft tissue defect is natural healed, the wound surface is often formed again due to a variety of reasons. The decreased function of the wound is an important factor, but its mechanisms are still unknown. Therefore, to study the mechanisms of the tactile dysfunction and explore how to promote the tactile function recovery of the wound skin are of great significance. Mammals experience tactile sense in the glabrous planta pedis area through Merkel cell-neurite complex. This complex is consists of Merkel cells and Aβ myelinated nerve endings. Previous studies have shown that Merkel cells play an important role in the formation of the tactile sense, while the planta pedis of rat can't distinguish texture of an object surface due to absent of it. Recent studies have shown that the Merkel cells can transduce mechanical stimulus into Ca2+ action potentials through Piezo2 ion channels when they under mecha-nical stimulation. The Ca2+ action potentials prompt the formation of chronic impulse in Aβ myelinated nerve endings, and transmit to the central nervous system to form a touch sense. This project intends to adopt a plantar full-thickness skin defect model in rats, and aim to study the Merkel cell, Piezo2 and Aβ afferent. By transplanting MCs or SCs separately, MCs and SCs combined transplantation, to observe tactile recovery effects of the wound skin and explore its possible mechanisms. This study will provide some preliminary basic research for a series of disease which are caused by human skin defect or hypopselaphesia.

皮肤软组织缺损自然愈合后由于多种原因导致创面再次形成，创面触觉功能减退是重要因素，但其功能减退的机制不详，因此研究创面触觉功能减退机制及探讨促进创面触觉功能恢复的方法具有重要意义。哺乳动物在足底等无毛区是由默克尔细胞神经突复合体感知触觉，该复合体由默克尔细胞和Aβ有髓神经末梢构成；默克尔细胞在皮肤触觉形成中占有主要地位，缺乏该细胞的大鼠足底不能辨别物体表面的质地。新近研究表明当默克尔细胞接受机械刺激后其细胞内的Piezo2离子通道把外周机械刺激转变为Ca2+动作电位，该电位促使Aβ有髓神经末梢形成神经冲动，传导至中枢形成触觉。本项目拟采用大鼠足底全层皮肤缺损动物模型，以默克尔细胞、Piezo2离子通道及Aβ传入神经为靶点，通过单独移植MCs、SCs以及联合移植默克尔细胞和雪旺氏细胞，观察比较创面触觉恢复效果，并探讨其可能机制，为人类皮肤缺损触觉减退导致的系列疾病提供一些前期基础研究

创面触觉功能减退的发生机制尚不明确。本课题研究了默克尔细胞联合雪旺氏细胞移植在创面触觉恢复中的作用。本研究从SD大鼠体内成功提取培养了默克尔细胞（MCs）和雪旺氏细胞（SCs），并通过Western Blot、免疫荧光完成了细胞鉴定。本课题发现，与SCs共培养的MCs中，离子通道蛋白Piezo2的表达在转录水平和蛋白水平上都显著升高，而当加入外泌体抑制剂GW4869抑制了该作用；进一步实验表明，SCs分泌的外泌体（SCs-exo）可诱导MCs的Piezo2表达。在大鼠足底创面模型中，MCs+SCs共同移植会显著增高创面收缩率和机械戒断阈值，且愈合皮肤默克尔细胞标记蛋白CK20和Piezo2蛋白表达量在联合移植组中表达较高，MCs与hAMSCs诱导的雪旺氏细胞（SCLCs）联合移植也具有同种促进作用。上述结果说明MCs和SCs联合移植可促进全层皮肤创面愈合并改善触觉恢复，该作用可能是通过SCs分泌的外泌发生的。该研究结果为皮肤缺损中触觉减退及系列疾病的治疗提供了新的依据和方向。目前，以发表本基金支持的论文15篇。