(A) RT-PCR analysis of human Cx43, Cx26, Cx32 mRNA expression in cultured lung fibroblasts. Representative results obtained by analysis of RNA extracted from 5 normal lung fibroblast cultures (N1-5) and 3 fibrotic fibroblast cultures (F1-3). (B) densitometry analysis of RT-PCR analysis of human Cx43 mRNA expression in cultured lung fibroblasts. RNA samples from human liver (Li) and heart (He) were also analyzed as positive controls. L: 100-bp ladder. (C) Human Cx43 mRNA level measured by quantitative real-time RT-PCR in cultured normal and fibrotic fibroblasts. Results obtained from commercially available human lung RNA sample has been reported as control. Relative quantification was performed by the 2-ΔΔCt method using as calibrator the value obtained from human normal lung. Data represent mean ± SD of 5 primary normal fibroblast lines and 3 fibrotic fibroblast lines. NF normal lung fibroblast, FF fibrotic lung fibroblast. §p = NS, * p < 0.05 in comparison to normal fibroblasts.