Histochemical, ultrastructural, and biochemical evidences for Azadirachta indica-induced apoptosis in benzo(a)pyrene-induced murine forestomach tumors.

Abstract

The present study reports aqueous Azadirachta indica leaf extract (AAILE)-mediated induction of apoptosis in a murine forestomach tumorigenesis model. Histochemistry-based quantification of apoptosis revealed enhanced apoptotic index in the forestomach tumors of mice receiving AAILE along with benzo(a)pyrene (B(a)P). Transmission electron microscopy confirmed the presence of classical morphological features of apoptosis including chromatin condensation/marginalization, nuclear fragmentation, and formation of apoptotic bodies. Scanning electron microscopy showed surface modifications on the transformed squamous epithelial cells and certain mitotic cells among them over the forestomach tumors of mice receiving only B(a)P. In tumors of the mice receiving AAILE along with B (a)P, such mitotic cells were found to be absent; however, certain cells showing shrinkage and blebbings (characteristics of apoptosis) were observed. DNA fragmentation was observed to increase exclusively in the tumors of mice that received AAILE along with B(a)P. Lipid peroxidation (LPO) levels decreased in forestomach tissues of mice in all the groups studied when compared to control counterparts. However, levels of LPO were found to increase in the tumorous tissue of mice that received AAILE along with B(a)P when compared to mice receiving only B(a)P. Taken together, observations of the present study suggest that A. indica induces apoptosis in B(a)P-induced murine forestomach tumors.