Abstract: Objective: To investigate the effect of octreotide on the proliferation and apoptosis of the rat airway smooth muscles (ASMCs) induced by transforming growth factor β1 (TGF-β1), and whether the SHZ domain-containing protein tyrosine phosphatase-1(SHP-1) is involved in the effect mentioned above or not.Methods: ①The cultured ASMCs were divided into the following 4 groups:control group, TGF-β1 group, TGF-β1+octreotide group and TGF-β1+octreotide+NSC87877group. The proliferation of ASMCs was detected by MTT assay. The level of phospho-SHP-1(Tyr536) was examined by Western blot.②The cultured ASMCs were divided into 3 groups:control group, 0.01 nmol/ml octreotide group and 0.1 nmol/ml octreotide group. Apoptosis of ASMCs was detected by Annexin-V FITC/PI double staining.Results: ①The absorbance (A_{490 nm}) value of TGF-β1 group was higher than that of control group (P<0.01).The A_{490 nm} value of TGF-β1+octreotide group was lower than that of TGF-β1 group (P<0.05) but higher than that of TGF-β1+octreotide+NSC87877 group(P<0.01).②The apoptotic rate of ASMCs in 0.01 nmol/ml octreotide treated group was higher than that in control group (P<0.01). There was no significant difference of opoptosis rate between control and 0.1 nmol/ml octreotide treated group.③The level of p-SHP-1 in TGF-β1 group was lower than that in control group(P<0.01). There were no significant differences between TGF-β1 group and TGF-β1+octreotide group.The p-SHP-1 in TGF-β1+octreotide+NSC87877 group was the lowest in all the groups.Conclusion: ①Octreotide can inhibit rat ASMCs proliferation induced by TGF-β1. ②Low dose octreotide induces ASMCs apoptosis, but high dose octreotide has no significant effect on ASMCs apoptosis. ③The growth inhibitory effect of octreotide is independent of SHP-1 signal pathway.

Key words: octreotide, transforming growth factor β1, SHP-1, airway smooth muscle cells