Chemopreventive action of Liv. 52 on DMBA-induced papillomagenesis in skin of mice.

DMBA (195 nmol/50 microliters of acetone/animal) was applied topically over the dorsal skin of the mice and tumors were promoted by repeated applications of croton oil (1% in acetone, three times per week) after two weeks of DMBA application. Skin papillomas appeared in 100% animals in control as well as in groups treated orally with Liv. 52 at post-initiational stages and continuously at peri-initiational and post-initiational stages of papillomagenesis. When Liv. 52 was given orally at the peri-initiational stage of papillomagenesis, the percentage of mice bearing tumors was 75% and the tumor mean per mouse was reduced to 4.0 +/- 1.63 as compared to 7.5 +/- 3.54 in the control group after 15 weeks of observation. The tumor mean per mouse was observed to be 4.75 +/- 0.55 and 2.5 +/- 0.57 in the groups treated orally with Liv. 52 at the post-initiational stages and continuously at peri-initiational and post-initiational stages of papillomagenesis respectively. Similarly, the cumulative number of papillomas after 15 weeks was 30 in the control group, which was reduced to 10 in the animals treated with Liv. 52 continuously at peri-initiational and post-initiational stages. The cumulative number of papillomas was also reduced to 16 and 19 in animals treated with Liv. 52 at peri-initiational and post-initiational stages, respectively.