Korelasi Ekspresi Cyclooxygenase-2 dengan Variasi Dosis 1,2- dimethylhidrazine, Jumlah , dan Ukuran Nodul Tumor pada Tikus Wistar sebagai Model Kanker Kolorektal

1,2-dimethylhydrazine (DMH) has been widely used to study chemically induced colon cancer. Cyclooxygenases (COXs) are important enzymes that affect carcinogenesis.COX-2 is the other isoform that can be induced by various stimuli, including inflammation, growth factors, and cytokines produced by tumor cells. The aim of this study is to investigate the correlation between the expression of COX-2 and variation doses of DMH, the number of colorectal tumor nodule and volume of colorectal nodule tumor. Colorectal carcinoma model induced by DMH. Six male Wistar rats were randomly divided in to 4 groups of seven. Group I is control group. Group II, III, and IV were given 20, 40, and 60 mg/kg BW of DMH respectively. DMH was subcutaneously injected in the hip area, once a week for 15 weeks. At week 26, all animals were sacrificed, the colon were removed and fixed in 10% buffer formalin for macroscopic and microscopic examination. Result of this study shows that increasing variation doses of DMH result in increasing the number of colorectal tumor nodule but not with the volume of colorectal tumor nodule. Microscopic examination by using HE staining shows that induction variation doses DMH result in 100% adenoma (20 mg/kg BW DMH), 33.3% adenoma and 66.7% adenocarcinoma (40mg/kg BW DMH), and 100% adenocarcinoma (60 mg/kgBW DMH). In this study we have also investigated that expression of COX-2 correlate with the number of colorectal tumor nodule and tumor volume (p