To develop a novel animal model of myocardial infarction:A research imperative

Although great progress has been made in therapeutic interventions for coronary artery disease(CAD), it is still the deadliest disease in the world. Currently animals that are similar to human beings in their cardiovascular pathophysiology are being used to explore the pathogenesis and therapy of CAD. There have been a series of developments in creating CAD animal models using mice, rats,rabbits, dogs, and pigs, but unfortunately there is still no acceptable model for human CAD. The ideal CAD animal model should satisfy several conditions as follows. First of all, it should have a pathophysiological process for CAD that is similar to humans. Second, it should be useable for assessing drug efficacy. The last and most important condition is that the model can be used to duplicate clinical therapeutic skills. The limitations of current methods for making animal models have meant that these models not only do not duplicate the actual pathogenesis, but also cannot be used to simulate clinical therapy, and do not support scientific evaluation of drug efficacy. Therefore, the development of a fit-for-purpose animal model for CAD is imperative for future research. Such a development will lead to rapid progress and greater efficiency in CAD research.This paper summarizes the present situation in the field of CAD animal models,and puts forwards ideas for developing a novel animal model of myocardial infarction.

Tongxinluo Improves Apolipoprotein E-Deficient Mouse Heart Function

Background： Our previous studies have shown that Tongxinluo （TXL）, a compound Chinese medicine, can decrease myocardial ischemia-reperfusion injury, protect capillary endothelium function, and lessen cardiac ventricle reconstitution in animal models. The aim of this study was to illuminate whether TXL can improve hypercholesterolemia-impaired heart function by protecting artery endothelial function and increasing microvascular density （MVD） in heart. Furthermore, we will explore the underlying molecular mechanism of TXL cardiovascular protection. Methods： After intragastric administration of TXL （0.1 ml/10 g body weight） to C57BL/6J wild-type mice （n = 8） and ApoE-/- mice （n=8）, total cholesterol, high-density lipoprotein-cholesterol, very-low-density lipoprotein （VLDL）-cholesterol, triglyceride, and blood glucose levels in serum were measured. The parameters of heart rate （HR）, lelt ventricular diastolic end diameter, and left ventricular systolic end diameter were harvested by ultrasonic cardiogram. The left ventricular ejection fraction, stroke volume, cardiac output, and let1 ventricular fractional shortening were calculated. Meanwhile, aorta peak systolic flow velocity （PSV）, end diastolic flow velocity, and mean flow velocity （MFV） were measured. The pulsatility index （PI） and resistant index were calculated in order to evaluate the vascular elasticity and resistance. Tile endothelium-dependent vasodilatation was evaluated by relaxation of aortic rings in response to acetylcholine. Western blotting and real-time quantitative reverse transcription polymerase chain reaction were performed for protein and gene analyses of vascular endothelial growth factor （VEGF）. lnamunohistochenaical detection was perlbrmed for myocardial CD34 expression. Data in this study were compared by one-way analysis of variance between groups. A value of P 〈 0.05 was considered statistically significant. Results： Although there was no significant decrease of cholesterol level （F = 2.300, P = 0.240）, TXL inhibited the level of triglyceride and VLDL （F- 9.209, P- 0.024 and F = 9.786, P ： 0.020, respectively） in ApoE-/- mice. TXL improved heart function of ApoE-/- mice owing to the elevations of LVEF, SV, CO, and LVFS （all P 〈 0.05）. TXL enhanced aortic PSV and MFV （F = 10.774, P = 0.024 and F = 11.354, P - 0.020, respectively） and reduced PI of ApoE-/- mice （1.41 ± 0.17 vs. 1.60 ± 0.17; P= 0.037）. After incubation with 10μmol/L acetylcholine, the ApoE-/- mice treated with TXL aortic segment relaxed by 44% - 3%, significantly higher than control group mice （F = 9.280, P = 0.040）. TXL also restrain the angiogenesis of ApoE-/- mice aorta （F = 21.223, P = 0.010）. Compared with C57BL/6J mice, the MVD was decreased in heart tissue of untreated ApoE-/- mice （54.0 ± 3.0/mm2 vs. 75.0 ± 2.0/mm2; F = 16.054, P - 0.010）. However, TXL could significantly enhance MVD （65.0 ± 5.0/mm2 vs. 54.0 ±3.0/mm2; F- 11.929, P = 0.020） in treated ApoE-/- mice. In addition, TXL obviously increased the expression of VEGF protein determined by Western blot （F = 20.247, P = 0.004）. Conclusions： TXL obviously improves the ApoE-/- mouse heart function from different pathways, including reduces blood fat tolessen atherosclerosis; enhances aortic impulsivity, blood supply capacity, and vessel elasticity： improves endothelium-dependent vasodilatation： restraines angiogenesis of aorta-contained plaque; and enhances MVD of heart. The molecular mechanism of MVD enhancement maybe relate with increased VEGF expression.

Molecular mechanism of Chuanxiong Rhizoma in treating coronary artery diseases

Objective:Most of the studies on the herb Chuanxiong Rhizoma(CR)have focused on the L-arginine-nitric oxide(NO)pathway,but the nitrate-nitrite-NO(NO_(3)^(-)–NO_(2)^(-)–NO)pathway was rarely investigated.Therefore,the aim of this study was to evaluate the effects and mechanisms of action of CR in coronary artery disease(CAD).Methods:The NO_(3)^(-),NO_(2)^(-)and NO levels were examined in the NO_(3)^(-)–NO_(2)^(-)–NO pathway.High-performance ion chromatography was used to quantify NO_(3)^(-)and NO_(2)^(-)levels.Then,NO was quantified using a multifunctional enzyme marker with a fluorescent probe.The tension of aortic rings was measured using a multi myograph system.Results:High content of NO_(3)^(-)and low content of NO_(2)^(-)was found in CR,and which could potently convert NO_(3)^(-)to NO_(2)^(-)in the presence of endogenous reductase enzyme.Incubating human coronary artery endothelial cells(HCAECs)with CR-containing serum showed that CR significantly decreased the NO_(3)^(-)content and increased the levels of NO_(2)^(-)and NO in the cells under hypoxic conditions.In addition,CR significantly relaxed isolated aortic rings when the L-arginine–NO pathway was blocked.The optimal concentration of CR for relaxation was 200 mg/m L.Conclusion:CR supplements large amounts of NO in cells and vessels to achieve relaxation via the NO_(3)^(-)–NO_(2)^(-)–NO pathway,thereby making up for the deficiency caused by the lack of NO after the L-arginine-NO pathway is suppressed.This study also supports the potential use of a traditional Chinese herb for future drug development.