[Inhibition of mRNA expression of silicotic collagen gene by tetrandrine].

Effects of tetrandrine (TT) on types I and III collagen gene mRNA in lung tissues of silicotic rats were studied with RNA dot blot and in situ hybridization by cDNA coding human and mouse Pro alpha 1 (I) and Pro alpha 1 (III) collagen. Results revealed types I and III collagen gene mRNA content in lung tissues of rats exposed to silica dust for two to four months was obviously greater than that in normal lung tissues (P < 0.05), and decreased significantly after treatment with TT (P < 0.05) by dot blot technique. In situ hybridization revealed silver granules of types I and III collagen gene mRNA were scattered in fibroblasts of alveolar septa in normal lung tissues, and in cellular nodes and thickened interstitia of silicotic tissues. It suggested aggregation of collagen in silicotic tissues was caused by enhancement of collagen gene expression, and TT could inhibit directly or indirectly transcription of collagen gene, and thus reduce synthesis of collagen protein in silicotic tissues.