title: An animal model of chronic rheumatic valvulitis induced by formalin-killed streptococci.
abstract: Rheumatic heart disease is the most severe complication of rheumatic fever. Till date, very few successful animal models of rheumatic valvular disease have been reported. This study aimed at developing a suitable animal model of chronic rheumatic valvulitis for further investigation and prevention of rheumatic heart disease. Lewis rats were immunized with one administration of formalin-killed and sonicated group A streptococci together with Complete Freund's Adjuvant every 7 days for three cycles followed by group A streptococci alone till killing. Control rats were administered adjuvants and saline. Rats in group 1 were killed 12 weeks after the initial injection. Rats in group 2 and control group were killed 24 weeks after the initial injection. Results 62.5% (5/8) of rats in group 1 developed myocarditis and 50% (4/8) developed valvulitis. Histological examination of cardiac sections showed only cellular infiltrates. In contrast, 75% (6/8) of rats in group 2 developed rheumatic-like myocarditis and 62.5% (5/8) developed chronic valvulitis. Histological manifestations of the hearts in group 2 animals involved not only acute damage such as cellular infiltrates, Aschoff-like cells, verrucous vegetation, but also chronic lesions such as fibrosis, vascular neogenesis. None of the rats (0/8) in control group presented myocarditis or valvulitis. Lewis rat repeatedly immunized with formalin-killed GAS may be a suitable animal model of chronic rheumatic valvulitis. It may be useful for future investigation of the pathogenesis and possible preventive strategies of human rheumatic heart disease.
authors.affiliation: Department of Cardiology, The Third Affiliated Hospital of Sun Yat-sen University, 510630, Guangzhou, People's Republic of China.
authors.forename: Xujing
authors.initials: X
authors.lastname: Xie
authors.forename: Hanjian
authors.initials: H
authors.lastname: Zhou
authors.forename: Jianlin
authors.initials: J
authors.lastname: Huang
authors.forename: Huanlei
authors.initials: H
authors.lastname: Huang
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Feng
authors.forename: Kaiyong
authors.initials: K
authors.lastname: Mei
authors.forename: Buyun
authors.initials: B
authors.lastname: Yu
authors.forename: Zulan
authors.initials: Z
authors.lastname: Su
authors.forename: Jieruo
authors.initials: J
authors.lastname: Gu
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D004195:Disease Models, Animal; D005260:Female; D005557:Formaldehyde / Q000494:pharmacology; D006321:Heart / Q000382:microbiology; D006349:Heart Valve Diseases / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D009205:Myocarditis / Q000276:immunology* / Q000473:pathology; D009206:Myocardium / Q000276:immunology / Q000473:pathology; D051381:Rats; D011917:Rats, Inbred Lew; D012214:Rheumatic Heart Disease / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D012215:Rheumatic Nodule / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D013290:Streptococcal Infections / Q000150:complications / Q000276:immunology; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000276:immunology* / Q000472:pathogenicity
chemical_list: D000942:Antigens, Bacterial; D005557:Formaldehyde