[The effect of cigarette smoke on the expression of transforming growth factor-beta1 mRNA and collagen type III in airways of asthmatic rats].

OBJECTIVE

To study the effect of cigarette smoke on the expression of transforming growth factor-beta l (TGF-beta1), and collagen type III in lung tissues, and therefore to investigate the mechanism of airway remodeling.

METHODS

Thirty male Wistar rats were randomly divided into a control group, an asthmatic group and a cigarette smoke treated group, with 10 rats in each group. The expression level of TGF-beta1 mRNA was measured by reverse transcription polymerase chain reaction (RT-PCR) and collagen type III by immunohistochemistry. The thickness of airway wall in each group was also measured. Software SPSS 11.0 was used for statistical analysis (data expressed as +/- s). Group comparison was made by one way ANOVA and Pearson correlation was used for correlation analysis.

RESULTS

The levels of TGF-beta1 mRNA and collagen type III in cigarette smoke treated group (0.42 +/- 0.04, 25.8 +/- 2.3) were higher than those in the asthmatic group (0.39 +/- 0.04, 22.9 +/- 3.1) and in the control group (0.26 +/- 0.04, 16.3 +/- 2.3). Compared to the control group, the levels were higher in the asthmatic group (F = 55.97, 35.61, all P < 0.05). The level of TGF-beta1 mRNA was positively correlated with the expression of collagen type III (r = 0.71, P < 0.05). The thickness of airway wall in the cigarette smoke treated group (23.3 +/- 2.4) microm2/microm was significantly higher than that in the asthmatic group (20.1 +/- 2.9) microm2/microm and the control group (11.6 +/- 2.4) microm2/microm;compared to the control group, it was higher in the asthmatic group (F = 53.68, P < 0.05).

CONCLUSION

Cigarette smoke can promote over-expression of TGF-beta1-mRNA in asthmatic rat airways, increase the expression of collagen type III and aggravate airway remodeling.