N-methyl-4-isoleucine cyclosporine attenuates CCl -induced liver fibrosis in rats by interacting with cyclophilin B and D.

BACKGROUND AND AIM: N-methyl-4-isoleucine cyclosporine (NIM811), a new analogue of cyclosporine A, can inhibit collagen deposition in vitro and reduce liver necrosis in a bile-duct-ligation animal model. However, whether NIM811 effects on CCl(4) -induced rat liver fibrosis, and the related mechanism has not been determined.

METHODS: A liver fibrosis model was induced in Wistar rats using CCl(4) for 6 weeks. Meanwhile, two different doses of NIM811 (low-dose 10 mg/kg and high-dose 20 mg/kg) were given to the CCl(4) -treated rats. Liver fibrosis was then evaluated according to histopathological scoring and liver hydroxyproline content. Serum alanine aminotransferase, aspartate aminotransferase and albumin levels, expression of matrix metalloproteinase-13, tissue inhibitor of metalloproteinase-1, α-smooth muscle actin and cyclophilin B and D in liver tissue were determined. Cyclophilin B and D were also studied in an hepatic stellate cell line.

RESULTS: Hydroxyproline content was decreased in both NIM811 groups compared with the model (P < 0.05). Liver necrosis and fibrosis were also attenuated in the NIM811 groups. NIM811 suppressed the expression of tissue inhibitor of metalloproteinase-1, transforming growth factor beta mRNA and α-smooth muscle actin protein in liver tissue. Expression of cyclophilin B in the fibrosis model was increased compared with the normal group (P < 0.05), and was decreased significantly in the low-dose NIM811 treatment group (P < 0.05), which indicated that cyclophilin B might have a profibrotic effect. In vitro studies revealed that cyclophilin B and/or D knockout were associated with collagen inhibition.

CONCLUSIONS: NIM811 attenuates liver fibrosis in a CCl(4)-induced rat liver fibrosis model, which may be related to binding with cyclophilin B and D.