Effect of Conjugated Linoleic Acid (CLA) Supplementation on Expression of B-Cell Lymphoma-2 (Bcl-2) in the Bladder Epithelium of Wistar (Rattus norvegicus) Rats Exposed to Cigarette Smoke.

Abstract

Bladder carcinoma is the 10th most common cancer in the world with an incidence about 3% of all cancers. The risk factor for smoking is found in 81% of all cases of bladder carcinoma. One of the protein groups associated with bladder urothelial carcinoma is B-Cell Lymphoma-2 (Bcl-2). Nicotine-derived nitrosamine ketone (NNK) contained in cigarette smoke would increase the proliferation of cancer cells through increased the expression of Bcl-2. The expression of Bcl-2 could be suppressed in the presence of Conjugated Linoleic Acid (CLA), a polyunsaturated fatty acid that has role in reducing the risk of cancer development which is reported in several studies, and then stimulate cell apoptosis. To determine the effect of CLA supplementation on Bcl-2 expression in the bladder of rats which is exposed to cigarette smoke. The study is an experimental study with true experimental posttest only control group design on Wistar rats. Sample was divided into 2 case groups: 0.5% of diet (125 mg) CLA supplementation in group A, 1% of diet (250 mg) CLA in group B; and 2 control groups: group without CLA supplementation (group C) as positive control and without cigarette smoke exposure (group D) as negative control. The study takes 60 days of exposure and then Bcl-2 expression on bladder epithelial was evaluated by immunohistochemistry staining. The results descriptively showed that rats in group C has an average Bcl-2 expression of 25.8±7.33%, while rats in group D has an average Bcl-2 expression 14.1±7.73% which means cigarette smoke exposure has been shown to increase the expression of Bcl-2 by 45.35% (p=0.019) in the bladder mucosa of experimental animals. Group B obtained an average Bcl-2 expression was 14.2±9.6% and has a significant difference when compared to group C, it shows that the addition of 1% CLA would reduce the expression of Bcl-2 by 44.96% (p=0.032). However, for group A, group with 0.5% diet of CLA supplementation did not showed decrease of Bcl-2 expression when compared to the group C (p=0.37). Conjugated Linoleic Acid (CLA) supplementation 1% of diet can reduce Bcl-2 expression in bladder epithelium of wistar rats (Rattus norvegicus) exposed to cigarette smoke.