[Influence of TGF beta(1) on expression of Smad7 mRNA and protein in rat liver cells].

OBJECTIVE: To investigate the influence of exogenous transforming growth factor beta 1 (TGFbeta1) on growth and signal inhibitor Smad7 protein and its mRNA in BRL cells (rat liver cell line). METHODS: BRL cells were incubated with TGFbeta1 and divided into 0 minute group, 90 minute group and 24 hour group according to the time of incubation with TGFbeta1. Morphologic changes were observed. The expression of Smad7 mRNA and protein was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immnuohistrochemistry. RESULTS: Growth stagnancy and morphologic change of cells was not seen among the three groups. The expression levels of Smad7 mRNA was the highest in 90-minute group and the lowest in 0-minute group, and the 24-hour group took the second place. Most of the Smad7 immune positive granules were observed in cytoplasm. CONCLUSION: TGFbeta1 does not induce growth stagnancy in BRL cells during the period of 90 minutes to 24 hours. There is a relation of effectiveness for a given period of time between the level of Smad7 and TGFbeta1 stimulation.