灭活链球菌诱导的实验性慢性风湿性心瓣膜炎

Experimental Chronic Rheumatic Valvulitis Induced by Inactive Streptococci

【目的】诱导慢性风湿性心瓣膜炎的动物模型,为风湿性心脏病的研究提供实验工具。【方法】Lewis雌鼠24只,随机分为A、B、C三组,每组8只。抗原D为经40g/L的多聚甲醛溶液灭活、超声处理、完全弗氏佐剂(CFA)乳化的A组链球菌(GAS),抗原E为经40g/L的多聚甲醛溶液及超声处理、不加CFA的GAS。A、B组皮下注射抗原D,每7d一次,3次后改为注射抗原E。C组为对照组,同样方法注射CFA及生理盐水。12周后处死A组,24周后处死B、C组。行血清抗链球菌溶血素"O"(ASO)、抗DNA酶B检查及心脏HE染色病理检查。【结果】ASO、抗DNA酶B检查均为阴性。A组分别有62.5%(5/8)及50%(4/8)发展为心肌炎和瓣膜炎,病理表现为单个核细胞浸润。B组分别有75%(6/8)及62.5%(5/8)发展为风湿性心肌炎和慢性瓣膜炎,心肌间质有Aschoff样细胞,瓣膜有单个核细胞、多核巨细胞浸润、成纤维细胞增生、血管新生及风湿性赘生物。C组心肌及瓣膜均正常。【结论】采用40g/L的多聚甲醛溶液灭活及超声处理的GAS免疫Lewis大鼠,处理时间至少24周,可诱导出与人类风湿性心脏病相似的慢性风湿性心瓣膜炎,且成功率较高。

Objective To induce an animal model of chronic rheumatic valvulitis for further investigation and prevention of rheumatic heart disease.Method Twenty-four female Lewis rats were randomly divided into three groups：A,B and C,8 rats per group.Antigen D was mixture of formalin-killed,sonicated group A and Complete Freund＇s Adjuvant（CFA）.Antigen E was formalin-killed and sonicated group A streptococci without CFA.Rats in group A and B were immunized by antigen D every 7 days,after 3 cycles followed by antigen E.Rats in group C were administered adjuvants and saline in same method.Rats in group A were killed 12 weeks after the initial injection.Rats in group B and C were sacrificed 24 weeks after the initial injection.Serum antistreptolysin-O（ASO） and anti-deoxyribonuclease B（anti-DNase B） of all animals were tested.Heart section were stained with hematoxylin and eosin for microscopic histological examination.Result Serum ASO and anti-DNase B of all animals were negative.Five and four of rats in group A developed myocarditis and valvulitis respectively.Examination of cardiac sections showed that only mononuclear cell infiltrates were present.Six and five of rats in group B developed rheumatic-like myocarditis and chronic valvulitis respectively.Histological manifestations of group B not only involved acute damage such as cellular infiltrates,Aschofflike cells,verrucous vegetation,but also chronic lesions such as fibrosis,vascular neogenesis.None of rats in group C presented myocarditis or valvulitis.Conclusion Lewis rats immunized by formalin-killed and sonicated group A streptococci for at least 24 weeks duration developed chronic rheumatic valvulitis which histological manifestations were similar to those seen in human RHD.Successful probability of this method to induce chronic rheumatic valvulitis was relatively high.