Abstract To explore the potential effect of bone marrow mesenchymal stem cell (BMSCs) transplantation combined with milrinone on the myocardial cell survival and cardiac function in heart failure. After isolation and culture of rat BMSCs and establishment of rat model of heart failure through intraperitoneal injection of adriamycin, the animals were administered with BMSCs through tail vein injection and/or with milrinone through the jugular vein injection. After that, echocardiography and Doppler images were used to evaluate cardiac function, and ELISA determined the milrinone concentration before and after intervention. The expression of myocardial specific proteins GATA-4, Cx43 and cTnI was determined. Compared with other treatments, administration BMSCs combined with milrinone more significantly improved cardiac function (p < 0.05). The BMSCs treatment had similar effect on the heart as milrinone (p > 0.05). The combined treatment obtained significantly increased expression of BNP levels and the highest expression levels of GATA-4, Cx43 and cTnI, compared to the BMSCs group. Combined treatment with BMSCs and milrinone effectively increase the expressions of GATA-4, Cx43, cTnI, and enhances healing of damaged myocardial cells, reducing lung resistance and plasma volume, and heart afterload. This treatment restores systolic and diastolic functions of the heart.

Exosomes, a kind of extracellular vesicle, are promising therapeutic agents for spinal cord injury (SCI). This article aimed to investigate effects of exosomes secreted from miRNA-29b-modified bone marrow mesenchymal stem cells (BMSCs) on SCI. Exosomes were extracted from BMSCs transfected with miRNA-29b or negative control (miR NC). SCI rats were injected intravenously with exosomes (control exosomes, miRNA-29b exosomes) and BMSCs (miR NC, miRNA-29b) through the tail vein. The expression of miRNA-29b in spinal cord tissues of SCI rats was detected by qRT-PCR. The hind limb motor function was evaluated by Basso Beattie Bresnahan (BBB) score. The histopathological damage and neuronal regeneration in spinal cord tissues was observed by HE staining and immunohistochemistry, respectively. The injection of miRNA-29b exosomes and miRNA-29b BMSCs both significantly increased the expression of miRNA-29b in spinal cord tissues of SCI rats (P<0.05). Compared with SCI rats, rats in the miRNA-29b exosomes and the miRNA-29b groups exhibited improved SCI, including increased BBB score, NF200 and GAP-43 positive neurons, as well as decreased contractile nerve cell numbers and GFAP positive neurons (all P<0.05). The relieving degree of SCI was significantly higher in the miRNA-29b exosomes group than in the miRNA-29b BMSCs group (P<0.05). Exosomes secreted from miRNA-29b-modified BMSCs were effective in the repair of SCI in rats.