Experimental Tuberculosis in Korean Chipmunks Treated with Steroid (Cortisone acetate) Injection and Whole Body Gamma-ray irradiation

Kim, E H; Wang, C S; Lew, Joon

Abstract

The detection of the tubercle bacilli is absolutely necessary to make a diagnosis of tuberculosis. It is generally accepted that the rate of detection of tubercle bacilli in the patient's sputum or urine is decreasing because of the abuse of anti-tuberculous agents. And the resistance of tubercle bacilli developed in the experimental animals such as mice and guinea pigs (Marks, 1972). Therefore the necessity for the development of a better diagnostic method has been mandatory. Recently, it has been reported that Korean chipmunks (Tamias sibiricus asiaticus, Gmelin) are highly susceptible to tubercle bacilli (Chang et al, 1971). Also it has been known that steroid administration and whole body irradiation induced immunosuppression experimentally and clinically. The purpose of the present investigation is to find a more accurate and prompt method for the detection of tubercle bacilli in a patient's urine or sputum and to apply the method clinically. Hence the effect of cortisone and gamma-ray irradiation on experimental tuberculosis in Korean chipmunks has been studied. Tubercle bacilli, (H37 Rv) were inoculated into the peritoneal cavity of chipmunks to induce tuberculosis. The Korean chipmunks were divided into eight experimental groups, each 10 animals it the test groups and 5 in the controls. Group I. Simultaneously treated: An injection with cortisone acetate 5 mg. was given daily after the bacilli inoculation. II. Pre-treated: An injection with cortisone acetate 5mg. was given daily for one week prior to bacilli inoculation. III. Post-treated: An injection with cortisone acetate 5mg. was given daily one week after bacilli inoculation. IV. Whole body gamma-ray irradiation Gamma-ray irradiation was given just before the bacilli inoculation. Groups V. VI. VII. and VIII. were controls. Every week during the experiment, 2 test and 1 control animals were sacrificed for observation of tuberculous changes in the peritoneal fluid, spleen, lung, liver and kidneys. The results are briefly summarized as follows 1. Compared with tuberculous control, Group I, II, and III revealed a mild decrease of body weight until the 4th week of the experiment. However Group IV showed a marked decrease of body weight until the 18th day and thereafter none had survived. 2. In Group I, tubercle bacilli were found in the peritoneal fluid, spleen, liver, and lung on the 7th day of the experiment. There were very significant tuberculous changes when compared with other groups. 3. Compared with Group I , Group IV showed less significant tuberculous change by pathologic examination and in the bacterial count (Ridley index) on 1st week of the experiment. There after, the disease process abruptly became severe. 4. These findings suggest that inoculation of tubercle bacilli into the Korean chipmunk with cortisone administration could be induced extensive tuberculosis in the short incubation period. So that, if sputum or another specimen of tuberculosis patients inoculated into immunosuppressed susceptible animals, such as cortisone treated Korean chipmunks, the rate of detection of tubercle bacilli would be higher and more accurate. Further effort is necessary for the clinical application of the use of the immunosuppressed animal as a better diagnostic tool.