ABSTRACT
BACKGROUND: Tianxiangdan (TXD) is used in traditional Chinese medicine because of its therapeutic and preventive effects in the treatment of coronary heart disease. However, the underlying mechanism of TXD in coronary microvascular disease (CMD) remains unclear. METHODS: A rat model of CMD was developed to study the mechanism of TXD activity. Sodium laurate was injected into the left ventricle of Sprague-Dawley rats to induce CMD. The rats were divided into six groups: a sham-operated (sham) group, an untreated CMD group, a low-dose TXD group (0.81 g·kg-1·d-1), a mid-dose TXD (TXD-M) group (1.62 g·kg-1·d-1), a high-dose TXD (TXD-H) group (3.24 g·kg-1·d-1), and a nicorandil (NCR) group (1.35 mg·kg-1·d-1). The effect of TXD on rats with CMD was observed after four weeks, and the mechanism of TXD in lipopolysaccharide (LPS)-induced cardiac microvascular endothelial cells (CMECs) was explored through treatment with 50 µg/mL TXD. RESULTS: Compared with the rats in the untreated CMD group, rats in the TXD-M and TXD-H groups showed higher left ventricular ejection fraction values, improved pathological structures, decreased expressions of interleukin (IL)-1ß, tumor necrosis factor-alpha (TNF-α), phosphorylated nuclear factor-κB inhibitor α (IκBα) and phosphorylated p65, and increased expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (P < 0.05). These effects were more pronounced in the TXD-H group than in the TXD-M group. In vitro experiments showed that TXD treatment increased the viability of LPS-induced CMECs and decreased the expression of IL-1ß, TNF-α, phosphorylated IκBα, and phosphorylated p65 (P < 0.05). However, the effects of TXD on CMECs were markedly reversed upon treatment with ML385 (Nrf2 inhibitor). CONCLUSION: The results showed that TXD exerts a protective effect on rats with CMD and related inflammatory injuries, and its anti-inflammatory mechanism is related to the activation of Nrf2 signalling.
ABSTRACT
PM2.5 samples were collected at the southwest suburb of Chengdu in spring (in May 2012 and 2014). The mass concentrations of PM2.5 were determined by the weight method, and 24 chemical elements in PM2.5 were analyzed by XRF. To study the pollution characteristics and sources of chemical elements, and the potential ecological risk of heavy metals in PM2.5, the Geo-accumulation Index, Enrichment Factor, and Potential Ecological Risk Index methods were applied, respectively. The results indicated that the mass concentrations of PM2.5 in spring at the southwest suburb of Chengdu were very high, compared with American EPA's Standard and National Standard level-â ¡. The detection of chemical element composition in PM2.5 showed that K and S were the main elements, whereas the contents of Ga, Cs, Co, Cd, and V were the lowest. The differences of elemental concentrations in PM2.5 showed relatively large differences, when compared with domestic and foreign representative cities. Se, Cd, As, Br, S, Pb, Cl and Zn were present at an extremely high level of geo-accumulation degree, which revealed that the pollution coming from human activities was serious. The analysis results of enrichment factor showed that Se, Cd, As, Br, Cl, Pb, Zn and S elements were highly enriched or hyper accumulated, Cu, Cs, Ni, Ga and Co elements were moderately enriched, and they were mainly from human activities rather than soil dust. Cr, Mn, Ca and V elements were mildly enriched, and they were from both natural sources and human activities. Na, Ti, Al, Si and Mg elements were scarcely enriched, and they were mainly from natural sources. The ecological risk assessment of heavy metals showed that the order of potential ecological risk inedx of heavy metals in PM2.5 was Cd > As > Pb > Cu > Zn > Ni > Co > Cr > Mn > V > Ti, while the ecological harm degree of Cd was extremely strong, and the whole potential ecological risk degree was very strong.
