Biol. Pharm. Bull. 30(8) 1427—1431 (2007)

damage the liver. Drug-induced liver injury is the most frequent cause of acute liver failure. Dimethylnitrosamine (DMN) is a potent hepatotoxin, carcinogen and mutagen. A high dose of DMN is administrated by one injection to the experimental animal, which causes submassive necrosis that resembles human fulminant hepatitis. Therefore this compound has been widely used as a model agent to study the mechanisms of liver injury. Silymarin, a known standardized extract obtained from seeds of milk thistle (Silybum marianum) is widely used in treatment of liver diseases of varying origin. It is composed of a mixture of four isomeric flavonolignans: silibinin, isosilibinin, silydianin and silychristin. Silymarin is widely used for protection against various liver diseases in Europe. It is also reported to offer protection against chemical hepatotoxins such as CCl4, 5) DMN, and alcoholic liver. Due to its proven hepatoprotective, silymarin is being used as a standard agent for comparison in the evaluation of hepatoprotective effects of CS. Cuscutae semen (CS), the ripe seed of Cuscuta chinensis Lam, belongs to an annual voluble parasitic herb of the family Convolvulacea. CS is used in traditional herbal medicine to invigorate the kidneys and consolidate kidney essence, nourish the liver, improve eyesight, arrest diarrhea and soothe an unborn fetus. It has been reported to have positive effects on chronic prostatitis, sperm abnormality, gynecological disease. chronic bronchitis and cancer growth. However, the effects of CS on acute liver injury and fibrosis have not yet been reported. Thus, we investigated the effects of CS on acute liver injury by biochemical analyses of serum, immunohistochemical analysis of alpha-smooth muscle actin (a-SMA) and proliferating cell nuclear antigen (PCNA) and hydroxyproline assay, using the DMN-induced liver injury model.