Combined effects of an antioxidant and caspase inhibitor on the reversal of hepatic fibrosis in rats.

UNLABELLED: We sought to determine the hepatic fibrosis-reversal effects upon simultaneous administration of lithospermate B (LAB), an anti-oxidant, and nivocasan, a caspase inhibitor, to rats compared with each compound alone. Liver fibrosis was induced in Sprague-Dawley rats by thioacetamide (TAA). Rats were treated with TAA and then given LAB and (or) nivocasan. Fibrotic areas were evaluated quantitatively by computerized morphometry. Apoptosis was assessed using a TUNEL assay, and immunohistochemical staining for malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4HNE) was performed to assess oxidative stress levels. Real-time quantitative PCR was used to quantify expression of fibrosis-related genes. The degree of hepatic fibrosis was significantly reduced in rats treated with LAB and nivocasan compared to either treatment alone (P < 0.001). Treatment with each compound significantly decreased expression of fibrosis-related genes, such as type I collagen α1 (col1α1), α-SMA and TGF-β1 (P < 0.05). Co-treatment with LAB and nivocasan further reduced col1α1 expression compared to treatment with either compound. A TUNEL assay revealed that hepatocyte apoptosis was significantly decreased in the group treated with nivocasan compared to other groups (P < 0.01). Immunohistochemistry showed a decrease in MDA and 4HNE, reflecting amelioration of oxidative stress, when LAB or LAB+nivocasan was administered compared to nivocasan alone (P < 0.01). Nivocasan was found to inhibit caspase-1, -3, -7, -9 and gliotoxin-induced death of rat-derived hepatic stellate cells was inhibited by nivocasan administration without overexpression of α-SMA.

CONCLUSIONS

Co-incidental administration of LAB and nivocasan suppressed oxidative stress and apoptosis, resulting in enhanced reversal of hepatic fibrosis in rat.