The Exploration Of The Wound And Sinus Tract Caused By Mycobacterium Tuberculosis Infection By Zebrafish Intramuscular Injection With Mycobaterium Marinum

Objective:Zebrafish infected with Mycobacterium marinum by intramuscular injection as a model of the refractory wound caused by Mycobacterium tuberculosis infection to explore the mechanism of the specific wound and the sinus tract in the subcutanious.Methods:We injected 1.095× 104 cfu Mycobacterium marinum into the dorsal muscle of the adult zebrafish to establish the model of the refractory wound caused by Mycobacterium tuberculosis infection, then we fellow up for survival and histology research, Hematoxylin-eosin and Ziehl-Neelsen staining were performed to validate the model. Deep sequencing was applied to investigate mycobacterium-induced gene expression changes of the model.Results:The experimental groups which contained 7 fish of each were followed up to 20 weeks for survival. There were 5 of the 7 fish infected with 1.095× 104 cfu Mycobacterium marinum developed refractory deep wound average 59 days later(end-point incidence 71.4%), and it did not healing after 2 weeks. The skin lesion appeared on the backside where was near the primary injection site at the earlist. We could found swelling of the skin and it developed to become a mass as the time went by. Wound would be seen when the mass ruptured. Apart from the backside, the wound could be found on the abdomen. Apart from the backside, the wound could be found on the abdomen. Histology research showed that large amount of epithelioid cells clump together in the muscle which formed granuloma-like lesion. Ziehl-Neelsen stain showed that fast-acid bacilli aggregated in the complete skin around the wound. Deep sequencing showed that the gene expression related with muscle proteins and perfurin were significantly down-regulated and the gene expression related with inflammation were significantly up-regulated in the infected wound zebrafish compared with the control zebrafish.Conclusion:Zebrafish infected with Mycobacterium marinum by intramuscular injection was a valuable model of the refractory wound caused by Mycobacterium tuberculosis infection. The gene expression related with muscle proteins and perfurin were significantly down-regulated and the gene expression related with inflammation were significantly up-regulated in the infected wound zebrafish compared with the control zebrafish. The mechanism of the formation of the subcutaneous sinus tract may be that the muscle maybe apoptosis and necrosis in anti-Mycobacterium tuberculosis immunologic process.