Kinetics of expression of connective tissue growth factor gene during liver regeneration after partial hepatectomy and D-galactosamine-induced liver injury in rats

Connective tissue growth factor (CTGF) is up-regulated by TGF-β1 during wound healing. The present study examined the expression of CTGF during regeneration after 70% partial hepatectomy (PH) or D-galactosamine (GalN)-injured liver in rats. CTGF, TGF-β1, and type I collagen mRNAs were semiquantified by a ribonuclease protection assay. After PH, TGF-β1 and type I collagen were increased at 2-6 h and at 12-48 h. CTGF increased at 6 h and returned to the control level thereafter. The ribonuclease protection assay of cultured hepatic stellate cells (HSC) and in situ hybridization suggest that the cells express CTGF along sinusoid might be HSCs. After GalN administration, CTGF increased at 2-96 h with a shoulder peak at 6-12 h followed by a main peak at 24 h. TGF-β1 and type I collagen were up-regulated with kinetics similar to those of CTGF. The different kinetics between PH and GalN regenerations indicate that regulation of CTGF in the two processes is different. Higher TGF-β1 expression after inflammatory/necrotic process in the GalN regeneration may caused the prolonged CTGF expression. (C) 2000 Academic Press.