Figure 2: Histopathological analysis of the therapeutic effects of Graptopetalum paraguayense (GP) and Silymarin on liver damage in rat models. (a) Schematic illustration of DMN-induced fibrosis in rats. Each rat was injected with either DMN or saline, as a control, three times per week for three consecutive weeks (triangles). Subsequently, either Silymarin or GP was dissolved in water and given orally from days 8 to 46 (black rectangles). Rats were weighed and euthanized each week (starting on day 11, which begins what are referred to as the first through sixth weeks). Blood samples were collected for biochemical analysis (summarized in Table 1), and livers were excised and weighed, followed by either fixing in formaldehyde for histopathology or isolation of RNA for microarray analysis. (b) Anatomical evaluation of damaged livers (left upper panel). Based on exterior views, the GP had greater therapeutic effect than Silymarin. Representative phenotypes of DMN-induced rat liver fibrosis and therapeutic effects of GP and Silymarin were characterized by histopathological scoring. The fixed liver samples were then processed for paraffin embedding and prepared for hematoxylin and eosin staining (to score necroinflammation in the fourth week) and for Sirius red/fast green collagen staining (to score for fibrosis in the sixth week) (right panel). Drug toxicity effects were also evaluated by scoring. No notable liver damage patterns were observed after the six-week course of treatment (left lower panel). The original magnification was 100×.