Investigation of Immune Biomarkers Using Subcutaneous Model of M. tuberculosis Infection in BALB/c Mice: A Preliminary Report

Expression pattern of the autophagy related proteins Beclin1 and LC3B in tuberculous wound tissues

Tuberculous wound therapy is a major challenge in clinical practice, due to the protracted disease course, high recurrence rate, and an unclear pathogenesis. We explored the expression patterns of Beclin1 and LC3B in tuberculous wound tissues in human tuberculous chronic wound and normal tissues was assayed by immunohistochemistry. Rat models of tuberculous wounding were induced by the Bacillus Calmette-Guerin (BCG) method. Beclin1 and LC3B protein expression in human tuberculous wound tissues differed from that of normal skin and non-tuberculous chronic wound tissues.In rat tuberculous wound tissues, expression of Beclin1 and LC3B mRNA time-dependently changed post-infection. Abnormal fluctuation of autophagy protein in the development of tuberculosis wound could be one of the causes for the repeated occurrence and protracted disease course of the tuberculous wound.

Modelling of cerebral tuberculosis in BALB/c mice using clinical strain from patients with CNS tuberculosis infection

Background & objectives:

Central nervous system (CNS) infection caused by Mycobacterium tuberculosis (MTB) is the most severe form of extrapulmonary tuberculosis (EPTB) due to a high level of mortality and morbidity. Limited studies are available on CNS-TB animal model development. The present study describes the development of a murine model of CNS-TB using a clinical strain (C3) isolated from the cerebrospinal fluid (CSF) of CNS-TB patients.

Methods:

Groups of mice were infected by the intravenous route with MTB C3 strain isolated from the CSF of CNS-TB patients. Brain and lung tissue were evaluated for bacterial burden, histopathology and surrogate markers of TB infection at 30 and 50 days post-infection.

Results:

Mice infected intravenously with MTB C3 strains showed progressive development of CNS disease with high bacillary burden in lungs at the initial stage (30 days), which eventually disseminated to the brain at a later stage (50 days). Similarly, high mortality (60%) was associated in mice infected with C3 strain compared to control.

Interpretation & conclusions:

The study showed development of a novel murine model of CNS-TB using the C3 strain of MTB that replicated events of extrapulmonary dissemination. The developed model would be helpful in understanding the pathogenesis of CNS-TB infection for the development of improved therapeutic interventions in future.