Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 7, 2006; 12(17): 2749-2755
Published online May 7, 2006. doi: 10.3748/wjg.v12.i17.2749
Modulatory effects of Azadirachta indica on benzo(a)pyrene-induced forestomach tumorigenesis in mice
Subhash Chander Gangar, Rajat Sandhir, Durg Vijay Rai, Ashwani Koul
Subhash Chander Gangar, Durg Vijay Rai, Ashwani Koul, Department of Biophysics, Basic Medical Sciences Block, Panjab University, Chandigarh, PIN-160014, India
Rajat Sandhir, Department of Biochemistry, Basic Medical Sciences Block, Panjab University, Chandigarh, PIN-160014, India
Supported by Council for Scientific and Industrial Research, New Delhi, India
Correspondence to: Ashwani Koul, PhD, Department of Biophysics, Basic Medical Sciences Block, Panjab University, Chandigarh, PIN-160014, India. ashwanik@pu.ac.in
Telephone: +91-172-2534124
Received: September 21, 2005
Revised: September 28, 2005
Accepted: November 10, 2005
Published online: May 7, 2006
Abstract

AIM: To evaluate the chemopreventive effects of aqueous Azadirachta indica (A indica) leaf extract (AAILE) against benzo(a)pyrene [B(a)P]-induced forestomach tumorigenesis in Balb/c mice.

METHODS: Female Balb/c mice were divided into four groups of 10-12 animals each. For induction of forestomach tumors, starting from d 14 of the experi-ment, mice of B(a)P and B(a)P + A indica groups were given intra-gastric instillations of B(a)P (40 mg/kg), twice a week for four weeks. Mice of A indica and B(a)P + A indica groups were orally administered with AAILE (100 mg/kg), two weeks prior to B(a)P instillations till the end of the experiment. After 22 wk of the first B(a)P instillation, mice were sacrificed and the forestomachs were analyzed for development of tumors, scanning electron microscopy (SEM) and histopathology.

RESULTS: Tumor incidence was observed to be 100% in mice that received only B(a)P. However, treatment with AAILE reduced the tumor incidence by 58.4% as observed in mice of B(a)P + A indica group when compared to that of B(a)P group. Similarly, the tumor burden and multiplicity were seen to decrease by 87.3% and 69.6% respectively in mice of B(a)P + A indica group when compared to those of B(a)P group. Scanning electron microscopy analysis showed that AAILE treatment itself did not cause any abnormalities on the surface architecture of forestomach epithelium. In tumorous forestomach, surface disruption was observed. Over the forestomach tumors of B(a)P group of mice certain rounded structures were seen in addition to closely placed tongue-shaped squamous cells. Interestingly, these rounded structures were not observed in B(a)P + A indica group of mice. Histopathalogically, the tumors were identical and diagnosed to be papillomas. Mice from control and A indica groups of mice did not develop any forestomach tumors and showed normal histo-architecture.

CONCLUSION: The present data suggest that A indica exerts chemopreventive effects against B(a)P-induced forestomach tumors in murine model. Because of lack of toxicity and ubiquitous bioavailability, A indica may play a promising role in future drug discovery and development as far as chemoprevention of cancer is concerned.

Keywords: Azadirachta indica; Benzo(a)pyrene; Chemoprevention; Histopathology; Scanning electron microscopy