ABSTRACT
BACKGROUND: The poor retention and survival of donor cells implanted into the myocardium limit the efficacy of cell therapy for myocardial infarction. Embedding cells in natural or synthetic biomaterials is a strategy to address this issue. OBJECTIVE: To explore the effects of bone marrow mesenchymal stem cells (BMSCs) encapsulated in hyaluronic acid (HA) hydrogel on cardiac function after myocardial infarction. METHODS:BMSCs from male Sprague-Dawley rats were isolated and cultured,and then HA-encapsulated BMSCs were cultured in vitro in the three-dimensional manner. A model of myocardial infarction was made by cutting the anterior descending artery of female Sprague-Dawley rats. After 1 week, the model rats were screened by ultrasonic testing and then eligible ones were randomly divided into four groups: PBS group (n=8), HA group (n=8), BMSCs group (n=29), and HA-encapsulated BMSCs group (n=29). At 1 week after modeling, the model rats underwent the secondary thoracotomy and the implants were injected into the marginal zone and infarcted region in corresponding groups. The survival rate and apoptosis of implanted cells were examined at post-injection day 1, week 1 and week 2 by RT-PCR and TUNEL respectively. At post-injection week 4, changes of cardiac microstructure and function were evaluated by histological examination and echocardiography. RESULTS AND CONCLUSION: Compared with the BMSCs group, HA hydrogel significantly enhanced the survival rate and reduced the apoptotic rate of BMSCs at post-injection day 1 and week 2 (both P < 0.05). At post-injection week 4, the HA+BMSCs combined treatment yielded the best recovery of cardiac function (P < 0.05). To conclude, HA hydrogel can act as a vehicle for BMSCs delivery and improve the beneficial effects of implanted BMSCs in early myocardial repair(within 2 weeks after infarction)via enhancing cell retention and survival.