Kurozu moromimatsu is the sediment of Kurozu, a jar-fermented Japanese black
vinegar produced from unpolished rice. Here, we examined the protective effects of Kurozu moromimatsu in a
diethylnitrosamine-induced model of
hepatocellular carcinoma. Thirty-two F344 rats were divided into two groups; the control group received basal CE-2 diet, and the Kurozu moromimatsu group received CE-2 diet containing Kurozu moromimatsu. At 16 weeks after initial intraperitoneal administration of
diethylnitrosamine (150 mg/kg/week), serum was collected from half the rats. These rats were sacrificed and the liver was resected for histological examination of
hematoxylin-
eosin-stained sections and assay of
matrix metalloproteinase-2 and
matrix metalloproteinase-9 levels in
tumor tissues.
Glutathione S-transferase placental form-positive foci were evaluated by immunostaining for
glutathione S-transferase placental form. The remaining rats were maintained for evaluation of survival. There were no significant differences of serum
transaminases,
tumor necrosis factor-alpha, and also no marked hepatic histological differences, between the two groups. However, the size of
hepatocellular carcinomas was greatly decreased and the levels of activated
matrix metalloproteinase-2 and -9 were significantly reduced in the Kurozu moromimatsu group. Further, survival was significantly prolonged in the Kurozu moromimatsu group compared with the control. These results indicate that Kurozu moromimatsu inhibited the growth of
hepatocellular carcinoma.