毛囊周期性中肿瘤坏死因子受体1的表达

Expression profile of TNFR-1 during hair follicle cycle

目的探讨肿瘤坏死因子受体1(TNFR-1)在毛囊周期中表达的规律及意义。方法采用石蜡切片免疫荧光、Western blot、RT-PCR检测小鼠毛囊生长期(出生后8、15 d,P8d、P15d)、退化期(出生后18 d,P18d)和静止期(出生后24 d,P24d)各时期TNFR-1的表达情况;免疫荧光检测毛囊细胞分化标记物AE13的周期性表达;TUNEL检测毛囊周期中的细胞凋亡情况。结果在4个时相点的皮肤中TNFR-1都存在不同强度的表达,RT-PCR与Western blot检测结果呈现出一致的规律,即从生长期中期(P8d)到生长期末期(P15d)呈现高表达趋势,退化期(P18d)和静止期(P24d)表达减弱并维持较低水平表达。免疫荧光的结果显示:TNFR-1表达在生长期主要表达于表皮层,毛囊的毛干和内根鞘以及毛母质,生长末期在外根鞘还出现明显表达;退化期在外根鞘、毛干及表皮层有表达,在次级毛芽出现很强的特异性表达;在静止期表皮层及杵状毛中呈现弱表达。AE13在生长期主要表达于表皮层以及毛干的皮质和毛小皮;退化期在毛干尤其是毛干基部端(即角质化区域和杵状毛形成区)强表达;在静止期弱表达于表皮层及杵状毛中。TUNEL检测凋亡结果显示:在生长期TUNEL阳性染色主要出现在表皮层,毛囊的毛干、内根鞘以及毛母质,生长末期还出现在外根鞘;在退化期出现在外根鞘、表皮层以及毛干基部端;在静止期P24d出现在表皮层、杵状毛、bulge区和皮脂腺。结论 TNFR-1表达于毛囊的各个时期,生长期中期到生长期末期呈现高表达趋势,退化期和静止期表达减弱并维持较低水平表达,其表达与毛囊细胞终末分化和凋亡有关。

different phase and Objective To determine the expression profile of TNFR-1 in the hair follicles of mice at explore its importance. Methods RT-PCR,Western blot analysis and immunofluorescence staining with paraffin section were adopted to detect the expression and distribution of TNFR-1 in mouse hair fol- licles at 4 time points, P8d, P15d, P18d and P24d respectively. Hair shaft differentiation marker AE13 was tested by immunofluorescence staining. The apoptosis of the hair follicle was detected by TUNEL staining. Results ern blot The expression intensity of TNFR-1 were distinct in all 4 time points in the skin. The results of West- analysis were consistent with those of RT-PCR, showing that from the middle anagen to very late ana- gen, TNFR-1 presented high expression. In the catagen and telogen, the expression of TNFR-1 was becoming lower than that of very late anagen, and stayed at a very low level. Immunofluorescence staining showed that in the anagen, TNFR-1 was mainly distributed in the epidermis, matrix, inner root sheath （IRS） and hair shaft. In the very late anagen phase, there was significant expression of TNFR-1 in the outer root sheath （ORS）. In the catagen phase, TNFR-1 was distributed in the epidermis and ORS, and expressed specifically and highly in the second hair germ. There was very low expression of TNFR-1 in the epidermis and club hair in the telogen phase. AE13 was expressed in the epidermis, hair cortex and hair cuticle in the anagen. In the catagen, there was a specific and high expression of AE13 in the hair shaft, especially in the proximal end of the hair shaft, that is, in the area of keratinization and club hair formation. Durinz the telo^en, there was a low expression ofAE13 in the epidermis and hair club. Through TUNEL staining, apoptotic cells were found in the epidermis, hair shaft, IRS and hair matrix during the anagen. In addition, apoptotic cells were observed in the ORS during late anagen, in the epidermis, ORS and proximal end of the hair shaft during catagen, and in the epidermis, hair club, bulge and sebaceous gland during the telogen. Conclusion TNFR-1 is expressed specifically and spatiotemporally in the hair follicle cycle, and its expression is significantly high in the middle anagen to very late anagen, and reduced and maintained in a mild level in the catagen and telogen phase, which is involved in cell differentiation and pro-apoptosis of hair follicle.