OBJECTIVETo observe the change of lipid metabolism and vascular endothelium as well as morphology of heart tissue in rats who were long-time exposed to moxa smoke with different concentrations in order to provide reference for safety assessment of moxa smoke on cardiovascular system.

METHODSOne hundred and sixty-eighty Wistar rats were randomly divided into a control group, a low-concentration group, a median-concentration group and a high-concentration group, 42 rats in each one. The rats were exposed to moxa smoke with concentration of 0%, 10%, 40% and 70%, respectively, for 20 min per day. After continuous intervention for six months, enzyme-linked immunosorbent assay (ELISA) was applied to measure the level of low density lipoprotein-receptor (LDL-r) and intercellular adhesion molecule-1 (ICAM-1) in blood serum in each group; the slices of heart tissue were stained with hematoxylin-eosin staining method to observe morphology change of heart tissue.

RESULTS(1) After the intervention of moxa smoke, the levels of LDL-r and ICAM-1 in the low-concentration group were not statistically different from those in the control group (both P > 0.05); the level of LDL-r in the median-concentration group was significantly increased, which was statistically different from that in the control group [(3.87 +/- 0.27) mg/mL vs (2.12 +/- 0.13) mg/mL, P < 0.01], however, the content of ICAM-1 was not obviously changed; although the level of LDL-r in the high-concentration group was presented with an escalating trend, it was not statistically different from that in the control group (P > 0.05) while the level of ICAM-1 was obviously increased (P < 0.01). (2) Under the light microscope, the abnormalities of cardiac muscle fibers and myocardial cell in each group were not been observed.

CONCLUSIONThe long-time intervention of low-concentration moxa smoke has no significant effects on lipid metabolism and vascular endothelium of rats, indicating that clinical application of low-concentration moxa smoke is relatively safe. The long-time intervention of moderate-concentration moxa smoke could significantly increase the clearance rate of cholesterol, implying the beneficial regulation of moxa smoke on lipid metabolism. The high-concentration moxa smoke could induce certain damage to vascular endothelium but its mechanism is in need of further research. The pathologic change of heart tissue could not be induced by moxa smoke with any concentration.