OBJECTIVETo observe the effects of Danlou Tablet (DT) on inflammatory reaction, and expressions of lipoprotein-associated phospholipase A2 (LP-PLA2), secretory phospholipase A2 (sPLA2), and to analyze potential mechanisms.

METHODSForty male Wistar rats were randomly and equally divided into five groups, i.e., the normal control group, the model group, the Western medicine (WM) group, the low dose DT group, the high dose DT group, 8 in each group. Rats in the normal control group were fed with basic forage for 12 successive weeks, while AS rat model was established in rats of the other four groups by feeding high fat and sugar forage plus intraperitoneal injection of vitamin D₃. Normal saline, atorvastatin calcium suspension (at the daily dose of 1.8 mg/kg), low dose DT suspension (at the daily dose of 450 mg/kg), and high dose DT suspension (at the daily dose of 900 mg/kg) were administered to rats in the model group, the WM group, the low dose DT group, the high dose DT group respectively by gastragavage for 8 successive weeks. The general condition of all rats was observed. Rats were sacrificed after gastric administration and their serum collected. Serum levels of lipids (TC, TG, HDL-C, LDL-C) and inflammatory factors [IL-6, TNF-α, monocyte chemoattractant protein 1 (MCP-1), oxidized low-density lipoprotein (ox-LDL), lipoprotein-associated phospholipase A2 (LP-PLA2), secretory phospholipase A2 (sPLA2)] were detected. Pathological changes of thoracic aorta were observed by HE staining. Protein and gene expressions of LP-PLA2 and sPLA2 in thoracic aorta were measured by Western blot and real-time fluorescent quantitative PCR respectively.

RESULTSCompared with the normal control group, rats in the model group were in low spirits and responded poorly. Typical atherosclerotic plaque could be seen in thoracic aorta of rats in the model group. Serum levels of TC, TG, LDL-C, IL-6, TNF-α, MCP-1, ox-LDL, LP-PLA2, and sPLA2 significantly increased (P < 0.05); protein and gene expressions of LP-PLA2 and sPLA2 in rat thoracic aorta increased (P < 0.05) in the model group. After 8 weeks of intervention, rats in 3 medication groups appeared active, and HE staining showed subsidence of plaque in rat thoracic aorta. Compared with the model group, serum levels of TC, TG, LDL-C, IL-6, TNF-α, MCP-1, ox-LDL, and LP-PLA2 decreased in 3 medication groups (P < 0.01, P < 0.05); serum sPLA2 level decreased, protein and mRNA expressions of LP-PLA2 and sPLA2 in rat thoracic aorta decreased in the WM group (P < 0.01, P < 0.05); protein and mRNA expressions of LP-PLA2 in rat thoracic aorta significantly decreased in the low dose DT group (P < 0.01, P < 0.05), and those of LP-PLA2 and sPLA2 decreased in the high dose DT group (P < 0.01, P < 0.05).

CONCLUSIONDT could fight against inflammatory reaction and AS possibly through inhibiting LP-PLA2 expression and reducing ox-LDL production.