白细胞介素10和转化生长因子β1在播散性毛孢子菌病小鼠模型中的动态研究

摘要

目的：观察播散性毛孢子菌病小鼠模型中白细胞介素-10（IL-10）、转化生长因子β1（TGF-β1）的动态表达，并探讨其在播散性毛孢子菌病中可能发挥的作用。方法50只雄性BALB/c小鼠随机分为试验组和对照组，每组25只，尾静脉分别接种阿萨希毛孢子菌（T.asahii）悬液和生理盐水，接种后3 d、7 d、14 d、21 d及28 d，对小鼠肾脏载菌量进行测定；取小鼠内眦静脉血，离心获得血清，通过双抗体夹心酶联免疫吸附试验（ELISA）检测两组小鼠不同感染时间血清IL-10和TGF-β1表达水平；实时荧光定量PCR检测两组小鼠不同感染时间脾脏IL-10 mRNA和TGF-β1 mRNA表达情况；采用Pearson相关分析对试验组小鼠不同感染时间肾脏载菌量与血清IL-10、TGF-β1、脾脏IL-10 mRNA、TGF-β1 mRNA表达量及试验组小鼠血清IL-10表达水平与脾脏IL-10 mRNA表达量、血清TGF-β1表达水平与脾脏TGF-β1 mRNA表达量进行相关分析。结果接种后3 d，试验组小鼠肾脏载菌量为（69.5±9.1）cfu/mg，接种后7 d，小鼠肾脏载菌量达到峰值，为（120.3±11.4） cfu/mg，其后载菌量逐渐降低，接种后28 d为（2.0±2.5）cfu/mg。试验组小鼠血清IL-10与TGF-β1表达水平在7 d较对照组明显升高，14 d时达到峰值，随后逐渐降低。接种后7 d、14 d、21 d，小鼠血清IL-10表达水平与对照组相比，差异有统计学意义（P均＜0.05）。接种后7 d、14 d、21 d，小鼠血清TGF-β1表达水平与对照组相比，差异有统计学意义（P均＜0.05）。试验组小鼠脾脏IL-10 mRNA、TGF-β1 mRNA表达量在7 d逐渐增高，14 d时达到峰值，随后逐渐降低至对照组水平。接种后7 d、14 d、21 d，小鼠脾脏IL-10 mRNA、TGF-β1 mRNA表达量与对照组相比，差异有统计学意义（P均＜0.05）。试验组小鼠血清IL-10表达水平与脾脏IL-10mRNA、血清TGF-β1表达水平与脾脏TGF-β1 mRNA表达量均呈明显正相关（P均＜0.05）。接种后7 d、14 d、21 d，试验组小鼠肾脏载菌量与血清IL-10、TGF-β1表达水平及脾脏IL-10 mRNA、TGF-β1 mRNA表达量均呈明显正相关（P均＜0.05），而接种后3 d和28 d，试验组小鼠肾脏载菌量与血清IL-10、TGF-β1表达水平及脾脏IL-10 mRNA、TGF-β1 mRNA表达量均无明显相关性（P＞0.05）。结论IL-10和TGF-β1可能参与了小鼠播散性毛孢子菌感染后的免疫应答反应，且表现为先增高后逐渐下降的趋势，可能减弱了机体清除T.asahii的能力，为T.asahii的存活提供了有利条件。%Objective To study the dynamic changes of interleukin10(IL-10) and transforming growth factor β1 (TGF-β1) in a mice model of disseminated trichosporonosis, and investigate their possible roles. Methods A total of 50 male BALB/c mice were randomly divided into the experimental group and the control group, and then they were respectively injected with organisms of Trichosporon asahii (T.asahii) or sterile saline via the tail vein. The liver, spleen, kidney, heart, lungs and brain of the mice were aseptically removed and cultured respectively, and then stained with HE and PAS methods;kindey fungal burden were measured;IL-10 and TGF-β1 mRNA levels in spleen were tested with qRT-PCR;the serum level of the IL-10 and TGF-β1 were determined by ELISA and compared with those from normal controls. By using the linear correlation analysis method, the correlation between the quantity of kidney fungal burden and the expression of IL-10 and TGF-β1 were analyzed. Results There were no other pathogenic fungus isolated except T.asahii in experimental group;after the time point of 3 or 7d, mice viscera tissue culture were all positive;14 or 21d, mice kindey tissue culture were all positive;28d, only 2 mice kindey tissue culture were positive. Mice viscera tissue cultures were all negative in control group. Experimental group fungal burdens of kidney at 3, 7, 14, 21 and 28d were (69.5±9.1) cfu/mg, (120.3±11.4) cfu/mg, (36.3±10.9) cfu/mg, (20.8±8.9) cfu/mg and (2.0±2.5) cfu/mg respectively. IL-10 and TGF-β1 mRNA levels of spleen and serum IL-10 and TGF-β1 levels of experimental group increased at 7d, which reached peak at 14d, then decreased to normal levels;at 7, 14 and 21d, comparing with the control group, there were signiifcant difference (P<0.05). Splenic IL-10 mRNA levels in disseminated trichosporonosis correlate positively with serum IL-10 levels(P<0.05), meanwhile splenic TGF-β1 mRNA levels in disseminated trichosporonosis correlate positively with serum TGF-β1 levels (P<0.05) after 7, 14 and 21d of the infection. IL-10 and TGF-β1 mRNA levels of spleen and serum IL-10 and TGF-β1 levels of experimental group correlate positively with fungal burden of kindey(P<0.05), but not after 3 or 28d of the infection (P>0.05). Conclusion IL-10 and TGF-β1 participate in the immune response of disseminated trichosporonosis, they increased at ifrst and then decreased to normal levels, which may reduce the body's ability to remove T.asahii, and provide T.asahii a favorable condition of survival.