No. of mice to be sacrificed at the following time points  
Day  -13 Day 0 Wk 2 Wk 4 Wk 6 Wk 8 Total
Control Regimens  
Untreated 5 5 5       15
RIF+INH+PZA+EMB     5 5 5 5 20
RIF+EMB     5 5 5 5 20
Test Regimen              
RIF+EMB+PZA     5 5 5 5 20
Total Mice 5 5 20 15 15 15 75
Treatment was initiated two weeks after infection at Day 0 and was administered for 8 weeks. Ethambutol was included to prevent the emergence of drug resistance in the nude mice. The same scheme was used for 75 BALB/c and 75 nude mice
Table 3: Scheme for experiment 2: assessment of PZA activity in M. tuberculosis infected BALB/c and nude mice.