Cysticercus fasciolaris infection induced oxidative stress and apoptosis in rat liver: a strategy for host-parasite cross talk.

Parasitic helminths have developed various strategies to induce or inhibit apoptosis in the cells of their host, thereby modulating the host's immune response and aiding dissemination to the host. Cysticercus fasciolaris, the larval form of Taenia taeniaeformis, parasitized different intermediate hosts like rats, rabbits, etc. and is cosmopolitan in distribution. In the present study, we have investigated host-parasite interactions and the resulting effect of C. fasciolaris in the liver of rat. Histology of the infected livers showed dilation and damages of hepatic cells near the parasite. Infected liver cells showed an increase in DNA fragmentation and chromatin condensation compared to the normal liver. Acridine orange and ethidium bromide dual staining revealed the presence of apoptotic cells in the infected liver. The decline in the mitochondrial membrane potential in the infected liver suggested that the observed apoptosis is mitochondria mediated. Occurrence of an elevated level of active executioner caspases 3/7 in the infected rat liver further confirms the occurrence of apoptosis. Different antioxidant enzymes were also evaluated and revealed a notable decline in the level of glutathione and glutathione-S-transferase activity leading to the augmented generation of reactive oxygen species. Results of the present study revealed that C. fasciolaris infection leads to apoptosis in the liver of rats which may be a surviving strategy for the parasitic larvae.