AIM:During liver regeneration cellular proliferation andapoptosis result in tissue remodeling to restore normalhepatic mass and structure.Main regulators of the apoptoticmachinery are the Bcl-2 family proteins but their roles arenot well defined throughout the liver regeneration.We aimedto analyze the expression levels of bcl-2gene family membersduring resection induced liver regeneration.METHODS:We performed semi-quantitative RT-PCR toexamine the expression level of bak,bax,bcl-2 and bcl-x_L in70% hepatectomized rat livers during the whole regenerationprocess and compared to that of the sham and normal groups.RESULTS:The expression of bak and bax was decreasedwhereas that of bcl-2and bd-X_L was increased in hepatectomizedanimals compared to normal liver at most time points.Wealso reported for the first time that sham group of animalshad statistically significant higher expression of bak and baxthan hepatectomized animals.In addition,the area underthe curve (AUC) values of these genes was larger in shamgroups than the hepatectomized groups.CONCLUSION:The expression changes of bak,bax,bcl-2and bcl-X_L genes are altered not only due to regeneration,but also due to effects of surgical operations. AIM: During liver regeneration of cellular proliferation and apoptosis in tissue remodeling to restore normal hepatic mass and structure. Main regulators of the apoptotic machinery are the Bcl-2 family proteins but their roles are well-defined throughout the liver regeneration. We aimed to analyze the expression levels of bcl -2gene family membersduring resected induced liver regeneration. METHODS: We performed semi-quantitative RT-PCR toexamine the expression level of bak, bax, bcl-2 and bcl-x_L in 70% hepatectomized rat livers during the whole regeneration process and compared to that of the sham and normal groups .RESULTS: The expression of bak and bax was decreasedwhereas that of bcl-2and bd-X_L was increased in hepatectomized animals compared to normal liver at most time points. Wealso reported for the first time that sham group of animalshad statistically significant higher expression of bak and baxthan hepatectomized animals. In addition, the area underthe curve (AUC) values ​​of these genes was larger in shamgroups than the hepatectomized groups. CONCLUSION: The expression changes of bak, bax, bcl-2 and bcl-X_L genes are altered not only due to regeneration, but also due to effects of surgical operations.