西罗莫司与未成熟树突状细胞延长小鼠皮肤移植存活时间的协同作用

The synergic effects of sirolimus and immature dendritic cells in prolonging survival time of skin allograft in mice

目的研究西罗莫司(SRL)对小鼠骨髓源树突状细胞(DC)分化及成熟的影响,观察西罗莫司与未成熟树突状细胞在延长小鼠皮肤移植存活时间中的协同作用。方法(1)在诱导C57BL/6小鼠骨髓细胞定向分化为DC时加入SRL,通过流式细胞仪检测CD11c、CD86及MHCⅡ类分子表达情况,经脂多糖(LPS)刺激后,再检测各分子表达的变化。(2)通过单向混合淋巴细胞反应(MLR)观察经SRL处理的DC刺激同种异基因小鼠T细胞增殖情况。(3)以C57BL/6小鼠为供者,BALB/c小鼠为受者建立皮肤移植模型。观察皮肤移植前7d经尾静脉注射供者未成熟DC及经胃管连续灌注SRL7d的受者移植皮片存活情况及组织学变化。结果(1)经SRL处理的DC表面CD11c表达仅有轻度降低,但CD86和MHCⅡ类分子表达明显减少。(2)MLR显示经SRL处理的DC刺激同种异基因小鼠T细胞增殖的能力降低。(3)受者皮肤移植术前联合应用供者未成熟DC和SRL,可减轻移植皮片炎症反应并延长其存活时间。结论SRL对DC分化的影响不明显,但可抑制DC发育成熟。受者术前应用SRL和未成熟DC可延长皮肤移植的存活时间。

Objective T To investigate the effect of sirolimus （SRL） on the differentiation, development, and maturation of mice bone marrow-derived dendritic cells （DC）, and the synergic effects of them in prolonging survival time of skin allograft. Methods （1） 13（2 of C57BL/6 mice were derived from bone marrow cells upon culture with SRL. The expression of CD11c, CD86 and major histocompatibility complex （MHC Ⅱ ） molecules was assessed with or without lipopolysaccharide （LPS） stimulation by flow cytometry; （2） The capacity of DC administrated by SRL to stimulate allogeneic T lymphocyte proliferation was examined by mixed lymphocyte culture （MLR） ; （3） A skin transplantation model was established with the recipients BALB/c mice and the donor C57BL/6 mice. Recipients were divided into control group （there was no administration before skin transplantation）, immature DC group （injection of donor C57BL/6 mice immature dendritic cells 2 × 10^6 via tail vein before skin transplantation）, SRL group （receiving oral SRL 3 mg/kg every day for 7 days before skin transplantation）, combined group （receiving an injection of donor C57BL/6 mice immature DC via tail vein and of oral SRL before skin transplantation）, and isogeneic group （in which the donors and recipients were both BALB/c mice and there was no administration before skin transplantation）. Survival time and histological changes of skin allograft were observed in different groups. Results （1） CD11 c expression on the DC in the presence of SRL was slightly decreased, but CD86 and MHC Ⅱ molecules significantly decreased, and SRL treatment could resist the stimulation of LPS; （2） MLR revealed that DC administrated by SRL could inhibit allogeneic T lymphocyte proliferation; （3） SRL treatment in combination with donor immature DC before transplantation could alleviate inflammation and prolong survival time of skin allograft in mice. Conclusions SRL does not alter differentiation but inhibit the maturation of DC. Sirolimus can cooperate with immature DC to prolong survival time of skin allograft in mice.