Effect of Xintongtai Regulating p38 MAPK/AP-1 on Traditional Chinese Medicine Syndrome Score and Collagen Fibers in VSMCs of Rabbits with Atherosclerosis： An Exploration Based on Theory of Heart Receiving Qi From Spleen / 中国实验方剂学杂志

ABSTRACT

Objective:To explore the effects of Xintongtai （XTT） on traditional Chinese medicine （TCM） syndrome score and collagen fibers in vascular smooth muscle cells（VSMCs） of rabbits with atherosclerosis in the regulation of p38 mitogen-activated protein kinase （p38 MAPK）/activator protien-1 （AP-1）signaling pathway. Method:A total of 120 rabbits of SPF grade were randomly divided into the sham operation group， combined phlegm and blood stasis model group， rosuvastatin group， and low-， middle-， and high-dose XTT groups. The rabbit model of atherosclerosis due to combined phlegm and blood stasis was established by exposing them to high-fat diet and balloon injury. Following modeling， the corresponding drugs were administered by gavage for eight weeks （2.3， 4.6， 9.2 g·kg^-1 for low-， middle-， and high-dose XTT groups and 0.55 mg·kg^-1for rosuvastatin group）. At the end of medication， the abdominal aorta was isolated and stained with htoxylin-eosin （HE） for observing the vulnerable plaque. Matrix metalloproteinase-9 （MMP-9） and tissue inhibitor of metalloproteinase-1 （TIMP-1） were detected by immunohistochemistry （IHC）. The collagen fiber decomposition in VSMCs was observed after Masson staining. The protein expression levels of p38 MAPK and AP-1 in aorta was assayed by Western blotting. The combined phlegm and blood stasis syndrome was scored based on TCM syndrome scoring scale. Result:Compared with the model group， XTT at each dose and rosuvastatin significantly decreased MMP-9 content， increased TIMP-1， down-regulated p38 MAPK protein expression， and weakened the nuclear translocation of AP-1 （<italic>P</italic><0.01）. Compared with the low-dose XTT group， the middle- and high-dose XTT groups and rosuvastatin group exhibited obviously lowered MMP-9，elevated TIMP-1， down-regulated p38 MAPK protein expression， and diminished AP-1 nuclear translocation （<italic>P</italic><0.05，<italic>P</italic><0.01）. The TCM syndrome scores of the middle- and high-dose XTT groups and rosuvastatin group were significantly improved as compared with that in the model group （<italic>P</italic><0.05，<italic>P</italic><0.01）. The comparison with the low-dose XTT group revealed a remarkable improvement in TCM syndrome score of the middle- and high-dose XTT groups and rosuvastatin group （<italic>P</italic><0.01）. As demonstrated by Masson staining， the smooth muscle fibers in the model group were arranged in disorder， accompanied by enhanced collagen decomposition， thinned fibrous cap， and increased plaque vulnerability. Compared with the model group， the VSMCs in each XTT group and rosuvastatin group were orderly arranged， manifested as decreased collagen fiber decomposition and increased plaque stability. Conclusion:XTT down-regulates the expression of p38 MAPK and MMP-9， increases the level of TIMP-1， reduces the nuclear translocation of AP-1， diminishes the decomposition of collagen fibers in VSMCs， and improves the score of combined phlegm and blood stasis syndrome. XTT alleviates arteriosclerosis due to combined phlegm and blood stasis by regulating p38 MAPK/AP-1 signaling pathway and downstream cytokines and stabilizing vulnerable plaques.