| Objective The present study was designed to evaluate the effects of Ligustrazine on content of TGF-Pi and type â… ,â…¢ collagen in lung tissue of silica-exposed rat. Method The 128 experimental wistar rats were randomly divided into control,silica and Ligustrazine groups. The tracheas of silica and Ligustrazine groups were exposed surgically under aseptic conditions, either 50 mg of silica dissolved in 1 ml sterile physiological saline was instilled into the trachea. Rats given the same volume of physiological saline intratracheally served as vehicle-treated controls. Rats in Ligustrazine group were injected intraperitoneally 50mg/kg/d Ligustrazine from 1 d after silica injection. Samples were collected on the ld,3d,7d,14d,21d,28d after silica injection. Lung/body coefficients were measured. Total inflammatory cell count and differential cell counts including lymphocytes,neutrophils,macrophages in bronchoalveolar lavage fluid(BALF) were detected by cell counter. Paraffin-embedded lung sections were stained with HE and observed under light microscope.Type â… , â…¢ collagen were stained with sirius red,detected by polarized light microscopy and quantified by Image Pro Plus. TGF-Pi protein were detected with streptavidin-peroxidase immunohistochemistry and quantified by Image-Pro Plus. Results 1. TGF-β1 expressed very little in the macrophages of control group while it markedly elevated in lung tissue of silica group.TGF-β1 content in Ligustrazine group decreased than that in silica group.There was significant difference of TGF-Pi integrated optical density between the two groups on the 7d after silica injection;2. Compared with control group, type â… , â…¢ collagen content in silica group increased at different levels. At differenttime points, type 1,111 collagen content in Ligustrazine group decreased than that in silica group. There was significant difference of type I collagen area percentage on thel4d,21d,28d after silica injection,type III collagen area percentage on the 28d between Ligustrazine group and silica group;3. Lung/body coefficient, the number of total inflammatory cells and the absolute number of differential cells including lymphocytes, neutrophils, macrophages in the BALF elevated in silica group and their elevations were not significantly suppressed by Ligustrazine treatment. Conclusion 1 .The elevation of TGF-|3i protein content in lungs of silica-exposed rats are significantly suppressed by Ligustrazine treatment;2.Ligustrazine treatment can effectively supress the elevation of type I ,111 collagen content induced by silica particles;3. The elevation of lung/body coefficient and the number of total inflammatory cells, the absolute number of differential cells including lymphocytes, neutrophils, macrophages in the BALF of silicotic rats are not significantly suppressed by Ligustrazine treatment. It is the first discovery that Ligustrazine can suppress the elevation of TGF-Pi and type I ,111 collagen content in lung tissue of silica-exposed rat in our study.
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