[Effects of taurine on type I and III collagen expression in rats lung exposed to silica]

To evaluate the effects of taurine in diet on the expression of type I and III collagen and collagen ratio at different time points in rats lung by image process technology.

Wistar rats were randomly divided into three groups: the saline instilled with a control diet (the saline treated group); silica instilled with a control diet (the silica treated group); and silica instilled with a diet containing 2.5% taurine (the taurine treated group). Animal models were established by the direct tracheal instillation of silica into rat lungs exposed surgically. The taurine concentration of serum was analyzed by means of HPLC. Paraffin embedded lung sections were stained with Sirius red. Polarization microscopy and Image Pro Plus Version 4.5 for windows were used for detecting type I and III collagen.

The concentration of taurine in serum of the taurine treated group was significantly elevated compared to the saline treated and silica treated group (P < 0.05 or P < 0.01). Sirius red polarization microscopy showed that type I and III collagen positive area percentage were elevated in the silica treated rats compared with the saline treated group. On the 7th, 14th, 21st, 28th day after silica instillation type I collagen positive area percentage was increased by 3.84, 3.77, 3.73, 9.83 respectively (P < 0.01), and type III collagen positive area percentage were elevated by a little in the silica treated rats compared with saline treated group. The taurine treatment significantly decreased elevation of silica type I collagen positive area percentage of lung by 2.39, 1.62, 7.13 at the 7th, 21st, 28th day respectively (P < 0.05 or P < 0.01), and type III collagen positive area percentage of lung by 2.62 at the 28th day (P < 0.05) compared with the silica treated group. The ratio of type I to III collagen was increased from the 7th day to 28th day after silica instillation, and reached 1.87 at the 28th day with the maximal ratio in the silica-treated group.

Treatment with taurine can effectively attenuate type I and III collagen expression in the rat lung induced by silica particles at different time points in our study.