Antigenotoxic and Antimutagenic Activities of Probiotic Lactobacillus rhamnosus Vc against N-Methyl-N′-Nitro-N-Nitrosoguanidine

Abstract

The present study provides experimental evidence of in vivo reduction of genotoxic and mutagenic activities of potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) by the strain Lactobacillus rhamnosus Vc. In vitro studies revealed that coincubation of MNNG with viable cells of L. rhamnosus Vc resulted in the detoxification of the parent compound accompanied with reduction in genotoxicity (69%) and mutagenicity (61%) as evaluated by SOS-Chromotest and Ames test, respectively. Oral feeding of probiotic bacteria L. rhamnosus Vc (10⁹ cfu) to Gallus gallus (chicks) for 30 days provided protection against MNNG-induced damage as evidenced from the significant decrease (P = 0.009) in glutathione S-transferase activity in the L. rhamnosus Vc+MNNG-treated chicks in comparison to the MNNG-treated chicks. Histopathology of colon and liver showed intact cells and mild inflammation in the L. rhamnosus Vc+MNNG-treated chicks, whereas heavy inflammation and degenerative changes were observed in MNNG-treated chicks. The results indicate that the probiotic L. rhamnosus Vc provided in vivo protection against MNNG-induced colon damage by detoxification of MNNG to less toxic metabolites.

ACKNOWLEDGMENTS

UGC-Meritorious Fellowship to Sheetal P. Pithva is gratefully acknowledged. We are thankful to Dr. Sunil Kanvinde, M.D., F. I. C. (Pathologist), consultant Histopathologist and Cytologist, Green Cross Histopathology and Cytopathology Centre, Ahmedabad, for assisting in histopathological analysis. We are also thankful to Dr. Amee Dodia, M.D., (Pathologist) for her extended help in histopathological analysis.