<![CDATA[Study chemically induced colon cancer with 1,2-Dimethylhydrazine (DMH) has been widely used.DMH induction to rodentia as animal model have been similarity with colon cancer morphlogy of human.Cyclooxygenase-2 (COX-2) are important enzymes that affect carcinogenesis.COX-2can be induced byvarious stimuli, including inûammation, growth factors, and cytokines produced by tumor cells. The aim ofthis study is to investigate the correlation between the expression of COX-2 and the doses variation ofDMH, the number and the size of colorectal tumor nodule.Six male Wistar rats were randomly divided into 4 groups each group consists of six rats. 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 for15 weeks. All animals were sacrificed at week 26th, the colon were removed and fixed in 10% bufferformalin for macroscopic and microscopic examination. The results of this study showed that there is acorrelation between various doses of DMH (P<0.05) with number of tumor nodule but not with the size ofcolorectal tumor nodule (P>0.05). Microscopic examination by using HE staining shows that inductionwith doses variation ofDMHresultin different morphololical form of tumour tissue. Induction of 20, 40,and 60 mg/kg BW DMH result in adenoma(100.00%),adenoma and adenocarcinoma (33.30% and 66.67%),and 100.00% adenocarcinoma respectively. The happens of COX-2 also correlate with in this studythatexpression of COX-2 correlate with the number and size of colorectal tumor nodule (P<0.05). However,there is no correlation between COX-2 expressionand doses variation of DMH. In conclusion, there is adose-dependent response in the number and the size of colorectal tumor nodule.]]>
