Effects of puerarin on pulmonary vascular remodeling and protein kinase C-α in chronic cigarette smoke exposure smoke-exposed rats

Abstract

In order to investigate the effects of puerarin on pulmonary vascular remodeling and protein kinase C-α (PKC-α) in chronic exposure smoke rats, 54 male Wistar rats were randomly divided into 7 groups: control group (C group), smoke exposure groups (S_4w group, S_8w group), puerarin groups (P_4w group, P_8w group), propylene glycol control groups (PC_4w group, PC_8w group). Rats were exposed to cigarette smoke or air for 4 to 8 weeks. Rats in puerarin groups also received puerarin. To evaluate vascular remodeling, alpha-smooth muscle actin (α-SM-actin) staining was used to count the percentage of completely muscularised vessels to intraacinar pulmonary arteries (CMA/IAPA) which was determined by morphometric analysis of histological sections. Pulmonary artery smooth muscle cell (PASMC) apoptosis was detected by in situ end labeling technique (TUNEL), and proliferation by proliferating cell nuclear antigen (PCNA) staining. Reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence staining and Western blot analysis were done to detect the PKC-α mRNA and protein expression in pulmonary arteries. The results showed that in cigarette smoke-exposed rats the percentage of CMA/IAPA and α-SM-actin expression were increased greatly, PASMC apoptosis was increased and proliferation was markedly increased; Apoptosis indices (AI) and proliferation indices (PI) were higher than in C group; AI and PI were correlated with vascular remodeling indices; The expression of PKC-α mRNA and protein in pulmonary arteries was significantly higher than in C group. In rats treated with puerarin, the percentage of CMA/IAPA and cell proliferation was reduced, whereas PASMC apoptosis was increased; The expression levels of PKC-α mRNA and protein were lower than in smoke exposure rats. There was no difference among all these data between S groups and PC groups. These findings suggested that cigarette smoke-induced pulmonary vascular remodeling was most likely an effect of the imbalance of PASMC proliferation and apoptosis. Puerarin appears to be able to reduce cell proliferation and vascular remodeling possibly through PKC signaling transduction pathway.

Keywords

puerarin / vessel remodeling / cigarette smoke / protein kinase C / apoptosis / proliferation

References

[1] ChurgA., TaiH., CoulthardT., et al.. Cigarette smoke drives small airway remodeling by induction of growth factors in the airway wall. Am J Respir Crit Care Med, 2006, 174(12): 1327-1334

[2] WrightJ. L., TaiH., WangR., et al.. Cigarette smoke upregulates pulmonary vascular matrix metalloproteinases via TNF-alpha signaling. Am J Physiol Lung Cell Mol Physiol, 2007, 292(1): L125-L133

[3] SantosS., PeinadoV. I., RamirezJ., et al.. Characterization of pulmonary vascular remodeling in smokers and patients with mild COPD. Eur Respir J, 2002, 19(4): 632-638

[4] WrightJ. L., PostmaD. S., KerstjensH. A., et al.. Airway remodeling in the smoke exposed guinea pig model. Inhal Toxicol, 2007, 19(11): 915-923

[5] KangT., LuS., WangL., et al.. Experimental study of vascular smooth muscle cell apoptosis induced by puerarin. Chin J Integrative Med Cardio-/Cerebrovascular Dis (Chinese), 2003, 1(12): 703-705

[6] NadziejkoC., FangK., BravoA., et al.. Susceptibility to pulmonary hypertension in inbred strains of mice exposed to cigarette smoke. J Appl Physiol, 2007, 102(5): 1780-1785

[7] XuY., StenmarkK. R., DasM., et al.. Pulmonary artery smooth muscle cells from chronically hypoxic neonatal calves retain fetal-like and acquire new growth properties. Am J Physiol, 1997, 273(17): L234-L235

[8] ItohH., YamamuraS., WareJ. A., et al.. Differential effects of protein kinase C on human vascular smooth muscle cell proliferation and migration. Am J Physiol Heart Circ Physiol, 2001, 281(1): H359-H370

[9] LeeS. D., LeeD. S., ChunY. G., et al.. Cigarette smoke extract induces endothelin-1 via protein kinase C in pulmonary artery endothelial cells. Am J Physiol Lung Cell Mol Physiol, 2001, 281: L403-L411