The Effect Of Mitochondrial Atp-sensitive K~+ Channel On Protein Kinase C Signal Pathway And Airway Smooth Muscle Cells Proliferation In Asthma

Objective:To investigate the effect of mitochondrial ATP-sensitive K~+ channel to mitochondrial membrane potential on the cell proliferation and change of Protein Kinase C alpha (PKCα) in airway smooth muscle cells (ASMCs)Methods:Thirty-six Sprague-Dawley (SD) rats was divided into six group: A. normal control group; B. normal + diazoxide group; C. normal + 5-hydroxydencanote (5-HD) group; D. asthma control group; E. asthma + diazoxide group; F. asthma + 5-HD group. Rhodamine 123 (R123) was used to detectedΔψm. The expression of PKCαprotein was examinated by western-blotting while PKCαmRNA was examinated by realtime PCR. The proliferation of ASMCs was detected by MTT colorimetric and cell cycle analysis.Results:(1). In group B, the Rhodamine 123 fluorescence intensity, the protein and mRNA levels of PKCα, the MTT A values and the percentage of S phase were markedly increased compared to group A, while percentage of G0/G1 phase was decreased (p<0.05). However, there were no significantly differences between group C and group A. (2). In group D and group E, the Rhodamine 123 fluorescence intensity, the protein and mRNA levels of PKCα, the MTT A values and the percentage of S phase were more increased than normal control group, and compared to group D, these values were more obvious in group E (p<0.05). Besides, after exposure to 5-HD for 24 hour, these values were decreased compared to asthma control group (p<0.05).Conclusions:in asthma ASMCs, the signal transduction pathway of PKCαmay be involved in cell proliferation, which is induced by the opening of mitoKATP and the depolarization ofΔψm.