Ki67 Immunohistochemistry staining. The slides were picked from the central transversal section, and stained for Ki67 which was a proliferation indicator located in the nuclei. Positive cells were rosa red in nuclei while the negative cells were blue. Pictures from the central artery and vein were taken for each group. A few positive cells could be found in the control group and DMOG-1 group, and tremendous positive cells could be found in the DMOG-2 group, indicating that in the DMOG-2 group the proliferation of the cells were more active.