Comparative study of the spinal tuberculosis model with the New Zealand rabbit

Abstract

Objective To establish and evaluate a rabbit model of spinal tuberculosis.Methods Sixty-two New Zealand rabbits were randomly divided into 4 groups:experimental A group (sensitized by complete Freund's adjuvant,n=20),experimental B group (not sensitized by complete Freund's adjuvant,n=20),control group (n=20) and blank group (n=2).After experimental A group was sensitized by complete Freund's adjuvant,a hole was drilled beneath the upper endplate of the L4 vertebral body and filled with a gelfoam sponge,which was infused with 0.l ml H37Rv standard Mycobacterium tuberculosis suspension.Experimental B group was filled with a gelfoam sponge infused with 0.1 ml H37Rv standard Mycobacterium tuberculosis suspension (culture medium and saline in control group).The blank group received no treatment.Results The survival rate of postoperative 8 w was 89.5％,60.0％,94.7％ and 100％ in the experimental A,experimental B,control and blank group respectively.The model was successfully established in all surviving rabbits of the experimental A group.The vertebral body destruction of the experimental A group was 50％ by X-ray and 83.3％ by CT reconstruction and MRI at 4 w,while it was 58.8％ by X-ray and 100％ by CT reconstruction and MRI at 8 w.All surviving rabbits of the experimental A group had vertebral destruction,granulation and necrosis while 17.6％ had psoas abscess at 8 w.Histopathology study revealed numerous lymphocytes and epithelioid cells,trabecular bone fracture and coagulative necrosis in the vertebrae of the experimental A group.The bacterium culture was 52.9％ positive.There were 75％ vertebrae damage and 100％ psoas abscess in experimental B group.Nither control nor blank group showed such changes.Conclusion A New Zealand rabbit of spinal tuberculosis model can be successfully established by drilling a hole in the upper endplate of the vertebral body,filling with gelfoam sponge infused with H37Rv standard Mycobacterium tuberculosis suspension after sensitized by complete Freund's adjuvant. Key words: Tuberculosis, Spinal; Models, Animal; Mycobacterium tuberculosis; Freund's adjuvant; Rabbits