血清BG、GM在不同免疫状态下肺烟曲霉菌感染大鼠中的实验研究

Experimental study of serum BG,GM in rats with aspergillus pneumoniae infection under different immune conditions

目的构建不同免疫状态下肺烟曲霉菌感染的大鼠模型,研究免疫缺陷严重程度与肺烟曲霉菌感染的关系。方法注射生理盐水及不同浓度的地塞米松和环磷酰胺建立不同免疫状态的大鼠模型,经鼻滴1×107CFU/mL烟曲霉菌标准菌株孢子悬液引起肺烟曲霉菌感染,并于感染1、3、5、7、9 d分别随机处死每组1/5大鼠,收集大鼠血液标本,动态观察半乳甘露聚糖(GM)、(1,3)-β-D-葡聚糖(BG)、白细胞计数(WBC)、中性粒细胞计数(NEUT)、CD4^(+)T细胞水平变化,同时取肺组织标本进行病理组织检查和真菌培养。150只大鼠均分为6组,组1为正常对照组,组2为低剂量免疫抑制组,组3为高剂量免疫抑制组,组4为正常状态感染组,组5为低剂量免疫抑制感染组,组6为高剂量免疫抑制感染组。结果与组1比较,组4在感染1~5 d时WBC明显升高,组6则在感染1~7 d WBC明显降低,但在感染9 d时明显升高,差异有统计学意义(P<0.05);吸入烟曲霉菌后,CD4T细胞水平均有降低的趋势,组4在感染7 d、组5在感染3 d、组6在感染5 d时与组内其他时期比较均明显降低,差异有统计学意义(P<0.05);组4、组5中,GM水平在感染3 d时明显高于组内其他时期,差异有统计学意义(P<0.05);组6 GM水平各时期与感染1 d比较,差异有统计学意义(P<0.05);BG水平在各组中均未见明显改变,差异无统计学意义(P>0.05)。组6肺组织呈重度水肿、出血、中性粒细胞浸润等表现,较组4病变程度明显加重。病变程度具有剂量依赖性和时间依赖性。结论在肺烟曲霉菌感染中,GM水平先于BG水平明显升高,不同免疫状态下GM水平不一,正常及免疫力轻度受损者,GM水平出现一过性增高,肺组织轻度受损,重度免疫抑制者GM水平持续升高,肺组织损伤明显加重,即不同免疫状态可影响肺烟曲霉菌感染的发展和转归。

Objective To establish rat models of aspergillus pneumoniae infection with different immune conditions and to study the correlation between the severity of immune deficiency and aspergillus pneumoniae infection.Methods Rat models of different immune conditions were established by injecting normal saline and different concentrations of dexamethasone and cyclophosphamide.Aspergillus pneumoniae infection model was induced by nasal drip of 1×107CFU/mL aspergillus fumigatus spore suspension,1/5 of rats were randomly killed after infection 1,3,5,7 and 9 days.Blood samples were collected to observe galactomannan(GM),(1,3)-β-D-glucan(BG),white blood cell count(WBC),neutrophil count(NEUT),CD4^(+)T cell levels.Lung tissue samples were also taken,pathological examination and fungi culture were performed.A total of 150 rates were divided into 6 groups on average,group 1 was normal control group,group 2 was low dose immunosuppression group,group 3 was high dose immunosuppression group,group 4 was normal infection group,group 5 was low dose immunosuppressive infection group,group 6 was high dose immunosuppressive infection group.Results Compared with group 1,WBC was significantly higher in group 4 after infection 1—5 days,and significantly lower in group 6 after infection 1—7 days,but significantly higher after infection 9 days(P<0.05).After inhalation of aspergillus,the levels of CD4^(+)T cell in group 4 after infection 7 days,group 5 after infection 3 days and group 6 after infection 5 days were significantly lower than those of other periods(P<0.05).In group 4 and group 5,GM levels after infection 3 days were significantly higher than those in other periods(P<0.05).In group 6,the levels of GM in other period had significant differences compared with after infection 1 days(P<0.05).BG levels had no significant change in each period(P>0.05).Group 6 showed severe edema,hemorrhage and neutrophil infiltration,which was more severe than group 4.The degree of lung lesion was dose-dependent and time-dependent.Conclusion In aspergillus pneumoniae infection,GM level increases more early than BG level.In different immune conditions,GM level is different.In normal and mild immunocompromised patients,GM level increases temporarily,lung tissue is slightly damaged,GM continuously increases in severe immunosuppressive patients,the lung injury obviously aggravates,that is to say,the development and outcome of aspergillus pneumoniae infection could be influenced by different immune conditions.