血清素阳性细胞在大鼠“内庭”“足三里”“伏兔”穴区皮肤组织中的分布

Distribution of serotonin-positive cells in local cutaneous tissues of different acupuncture points at hindlimbs in rats

目的:观察血清素在大鼠后肢不同穴区局部组织中特定细胞上的表达,探讨腧穴之间组织学上的差异。方法:以6只正常SD大鼠为实验对象,选取其后肢"内庭""足三里"和"伏兔"为代表穴区。用荧光免疫组织化学法对每个穴区局部组织进行染色,所选用的抗体和生物学标记物包括血清素、鬼笔环肽、核酸特异性荧光染料DAPI和降钙素基因相关肽(CGRP)。采用共聚焦显微镜对标记的穴区组织进行观察,并分析血清素阳性细胞的分布特点。结果:血清素阳性细胞主要位于穴区的真皮和皮下组织,在真皮浅层接近表皮的部位呈扁平或不规则形,在真皮深层和皮下组织主要呈圆形和椭圆形而且集中分布在鬼笔环肽标记的血管样结构周围,在CGRP阳性神经纤维周围亦有大量分布。血清素阳性细胞以"内庭"穴区居多,"足三里"和"伏兔"穴区依次减少(P<0.01)。结论:皮肤血清素阳性细胞是不同穴区局部组织中的重要细胞成分,而且依穴区所在部位的不同存在数量上的差异。提示针刺对血清素发挥调节作用的强弱可能与选取腧穴所在部位血清素阳性细胞的数量有关。

Objective To investigate the expression of serotonin(5-HT)in local tissue of different acupoint regions at the hind limbs of rats.Methods A total of 6 male SD rats were used in the present study.The local tissues of"Neiting"(ST44),"Zusanli"(ST36)and"Futu"(ST32)at the hindlimbs were dissected after transcardiac perfusion with fixative solution containing 4%paraformaldehyde,phosphate buffer,etc.,fixed again in 4%paraformaldehyde and cut into sections(at 20μm thick).Then,the tissue sections were subjective into immunofluorescence stain for displaying 5-HT positive cells and calcitonin gene-related peptide(CGRP)-positive fibers,vessel-like structure(labelled with phalloidin)and cellular nucleus(labelled with DAPI),separately.After that,the tissue samples were observed and recorded using a laser confocal microscope.Results The 5-HT labeled cells presented flat or round form in the local tissues of the 3 acupoint regions.These cells were mainly located in the dermis and subcutaneous tissue,and concentrated around the vessel-like structure and CGRP-positive nerve fibers.The number of cutaneous 5-HT positive cells was most in ST44(156.6±12.1),and fewer in ST36(83.5±18.2)and ST32(53.3±5.2)in turn.Conclusion 5-HT-positive cell is an important member in local tissue of acupoints(ST44,ST36 and ST32),and varies in number according to their locations,suggesting an involvement of different densities of 5-HT-positive cells in different levels of regulatory effects of acupuncture stimulation of these acupoints.