[Electroacupuncture improves long-term survival of myocardial infarction mice by promoting myocardial angiogenesis and inhibiting ventricular remodeling].

OBJECTIVE: To investigate the mechanism of electroacupuncture (EA) in improving the long-term survival rate of mice after myocardial infarction by promoting angiogenesis and inhibiting ventricular remodeling. METHODS: A total of 102 male C57BL/6 mice were randomly divided into sham operation, model and EA groups (n=34 /group). The myocardial infarction model was established by permanent ligation of the anterior descending branch of the left coronary artery. Beginning from the 3rd day after ligation, EA (2 Hz/20 Hz) was applied to bilateral "Neiguan" (PC6) and "Ximen" (PC4) for 30 min, once a day for 28 days. The survival rate in 140 d was recorded and the left ventricular ejection fraction (EF) calculated by using echocardiography after the treatment. The left cardiac ventricular tissue was cut into sections to be stained with Masson's trichrome, wheat germ agglutinin (WGA) or α-smooth muscle actin (α-SMA) immunohistochemistry method, followed by measuring the collagen area in the marginal region of myocardial infarction and calculating the collagen volume fraction (for assessing the severity of myocardial fibrosis), measuring the sectional area of cardiomyocytes (for assessing the degree of myocardial hypertrophy), and ob-serving the newborn blood vessels and calculating the ratio of neovascularization area (for assessing the state of angiogenesis). The expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1α protein in the boundary area of myocardial infarction were detected by Western blot. RESULTS: After modeling, the survival rate, EF, and the thickness of the left cardiac ventricle were significantly decreased (P<0.01), whereas the percentage of collagen deposition area, sectional area of cardiomyocyte, percentage of angiogenesis area, and the expression levels of VEGF and HIF-1α proteins were significantly increased (P<0.01) in the model group relevant to the sham operation group. Compared with the model group, the survival rate, EF, the thickness of the left cardiac ventricle, the percentage of angiogenesis area, and the expression levels of VEGF and HIF-1α proteins were significantly increased (P<0.05, P<0.01), while the percentage of collagen deposition area and the sectional area of the cardiomyocyte were considerably decreased in the EA group (P<0.01, P<0.05). CONCLUSION: EA of PC6 and PC4 can significantly improve the cardiac function and long-term survival rate in mice with myocardial infarction, which may be related to its functions in up-regulating the expression of HIF-1α and VEGF to promote angiogenesis and in inhibiting ventricular remodeling.

Preparation and evaluation of biocompatible long-term radiopaque microspheres based on polyvinyl alcohol and lipiodol for embolization.

The aim of this work was to develop long-term radiopaque microspheres (LRMs) by entrapping lipiodol in biocompatible polyvinyl alcohol with multiple emulsions chemical crosslinking method. The high content of lipiodol (0.366 g/mL) was hardly released from LRMs in vitro and the radiopacity could maintain at least 3 months after subcutaneous injection in mice without weakening. A series of tests was performed to evaluate the feasibility of LRMs for embolization. LRMs were proved to be smooth, spherical, and well dispersed with diameter range of 100-1200 µm. Young's modulus of LRMs was 55.39 ± 9.10 kPa and LRMs could be easily delivered through catheter without aggregating or clogging. No toxicity of LRMs was found to mouse L929 fibroblasts cells and only moderate inflammatory in surrounding tissue of mice was found after subcutaneous injection of LRMs. After LRMs were embolized in renal artery of a rabbit, the distribution and radiopacity of LRMs in vivo were easily detectable by X-ray fluoroscopy and computed tomography (CT) imaging, respectively. More accurate distribution of LRMs in embolized kidney and vessels could be detected by high-revolution visualization of micro-CT ex vivo. In conclusion, the LRMs were proved to be biocompatible and provide long-term radiopacity with good physical and mechanical properties for embolization.

Research of novel biocompatible radiopaque microcapsules for arterial embolization.

Embolic agents, such as microparticles, microspheres or beads used in current embolotherapy are mostly radiolucent, which means the agents are invisible under X-ray imaging during and after the process of embolization, and the fate of these particles cannot be precisely assessed. In this research, a radiopaque embolic agent was developed by encapsulating lipiodol in polyvinyl alcohol. The lipiodol-containing polyvinyl alcohol microcapsules (LPMs) were characterized and evaluated for their morphology, size distribution, lipiodol content, lipiodol release, elasticity, and deliverability through catheter. The radiopacity of LPMs in vials and in living mice was both detected by an X-ray imaging system. The biocompatibility of LPMs was investigated with L929 cells and in mice after subcutaneous injection. Embolization of LPMs to a rabbit kidney was performed under digital subtraction angiography (DSA) and the radiopacity of LPMs was verified by computed tomography (CT).

[Pharmacokinetics of doxorubicin alginate microspheres and evaluation of its hepatic arterial embolization in vivo].

AIM: To investigate the pharmacokinetics of doxorubicin alginate microspheres (DOX-AM) in vivo after hepatic arterial embolization. METHODS: China miniature pigs were chosen as the experimental animals. Transcatheter hepatic arterial chemoembolization (TACE) with DOX-AM (experimental group), lipiodol and DOX (DOX-lipiodol, control group 1), and infusion with DOX (control group 2) were performed after angiography and superselection of an intrahepatic branch of hepatic artery. After chemoembolization or infusion, the blood was collected at different time intervals. Drug concentration in plasma was measured by HLPC and the parameters of pharmacokinetics were calculated. RESULTS: The values of T1/2, AUC, Cmax, and MRT of the DOX-AM were significantly different from those of control group 1 and control group 2. After embolization, the DOX-AM embolized in the vessel and still retained there at 8 weeks. The digital subtraction arteriography (DSA) and computerized tomography (CT) showed the reliable embolization results. The histological examination indicated that the liver damnifications were changed transitorily in all groups (P < 0.05) and were recovered within two weeks. The liver damnifications increased in following order: DOX < DOX-AM < DOX-lipiodol. CONCLUSION: DOX-AM showed definite property of delayed release of drug in liver, and increased the retention time and concentration of DOX after embolization in vivo.