A Preliminary Protocol for Induction of Tuberculosis Spondylitis by Mycobacterium Tuberculosis Strain H37R: In-vivo New Zealand White Rrabbits Model

Proper animal model is a critical prerequisite of any experimental study, while it is a lack for tuberculosis spondylitis. This study aimed to validate a protocol for induction of tuberculosis spondylitis in an animal model. Ten New Zealand white rabbits were used and divided randomly into four experimental groups (n = 8), with 2 rabbits in each group, and the control group (n = 2). A 0.2 mL suspension of 108 CFU/mL H37Rv strain M. tuberculosis was delivered into the drilled hole with a depth of 6-10 mm at the midpoint of the 12th thoracal corpus compared with the saline in the control group. Evaluation of imaging examination by using plain X-ray was done within the targeted time followed by euthanasia protocol. A survival rate of 100% was observed in the present study with all rabbits having stable vital signs during the incubation period. Group 3 with an incubation period of 6 weeks showed the highest success rate for inoculation of M. tuberculosis bacteria in which 7 samples were positive. This was followed by group 2 (75%, incubation 4 weeks), group 1 (37.5%, incubation 2 weeks), and group 4 (12.5%, incubation 8 weeks). The high positive rates were also reported by using culture and PCR staining, 62.5% and 75%, respectively. A slight destruction of the vertebral body was observed in both groups 2 and 3 starting at 4 weeks, postoperatively. Histopathology specimen exhibited an infiltration of numerous inflammatory cells. Establishment of spondylitis tuberculosis model by using New Zealand white rabbit could be successfully formed through 0.2 mL suspension of 108 CFU/mL M. tuberculosis strain H37Rv with a direct inoculation method towards the midpoint of the 12th thoracal vertebral body. In addition, this model showed a high positive rate with a 100% survival rate in both control and 4 treatment groups.