[Down-regulation of expression of α- smooth muscle actin in airway smooth muscle cells by allicin and its mechanisms].

OBJECTIVE:To investigate the effect of allicin on the expression of α-smooth muscle actin (α-SMA) in airway smooth muscle cells (ASMC), and to evaluate the mechanism of allicin on inhibition of airway remodeling. METHODS:The human ASMCs were treated for 48 hours with 0, 2.5, 5.0, and 10.0 μmol/L allicin, respectively, and the total RNA and protein of the cells were collected. The mRNA expression of α-SMA was determined by real-time polymerase chain reaction (PCR) analysis. The protein expression of α-SMA and phosphorylation Smad1 (p-Smad1) were assessed by Western blotting analysis. RESULTS:After the treatment with allicin for 48 hours in a dose of 0, 2.5, 5.0, and 10.0 μmol/L respectively, the mRNA expression of α-SMA was down-regulated (0.543±0.121, 0.354±0.072, 0.223±0.058, and 0.191±0.034, respectively), with statistically significant difference among groups (all P<0.05), and the protein expression of α-SMA and p-Smad1 was also gradually down-regulated in a dose-dependent manner [α-SMA protein (grad value ratio): 0.96±0.02, 0.72±0.16, 0.54±0.11, and 0.31±0.14, respectively; p-Smad1 protein (grad value ratio): 0.94±0.03, 0.76±0.13, 0.62±0.11, and 0.43±0.12, respectively), with statistically significant difference among groups (all P<0.05). CONCLUSION:Allicin depresses the mRNA and protein expression of α-SMA, and inhibits p-Smad1 in a dose-dependent manner, thus interrupts the transforming growth factor-β and Rho kinase signal pathway.