| Objective: Our objective was to study the role of exosomes derived from bonemarrow mesenchymal stem cells (BMSCs) on neovascularization in myocardial infactionmodel.Methods: BMSCs were isolated from bone marrow mononuclear cells by method ofdifferential adhesion and cultivated to the sixth generation. HUVECs were cultivated to thesecond generation.. Exosomes from media of BMSCs and HUVECs were isolated byExoQuick-TC kit. The angiogenic effect of exosomes from BMSCs was evaluated bymeans of Matrigel tube-formation assay in vitro. Tube formation was evaluated inHUVECs that had been cultured for12hours with PBS (the blank control group), BMSCsexosomes (the experiment group), BMSCs exosomes stored at-80℃, HUVEC exosomes(the positive control group), or BMSCs exosome-depleted conditioned medium (thenegative control group). To evaluated the angiogenic effect of exosomes from BMSCs invivo, the rat myocardial infarct models were created and injected with PBS, BMSCsexosomes, HUVEC exosomes, or BMSCs exosome-depleted conditioned mediumintramyocardially in the peri-infact zone. Four weeks after MI, we detectedneovascularization by anti-beta galactosidase staining and anti-alpha SMA staining, thecardiac fibrosis by Masson’s Trichrome staining and the cardiac function by UCG.Results: In vitro, the tube length (pixel/field) of the experiment group was14576.14±767.62, which was significantly greater than the blank contorl group (10496.52±258.00)and the negative control group (11215.09±692.74; P<0.05), but similar with the positivegroup (12729.41±752.63; P>0.05). the frozen group(12328.63±1109.99) was significantly greater than the blank contorl group and was significantly lower than theexperiment group. In vivo,4weeks after MI, neovascularization of capillaries in theperi-infact zone was significantly induced in the experiment group (1152.17±91.40/field)and the positive control group (998.50±201.16/field) than other groups (the blank controlgroup:704.50±138.85/field and the negative control group:704.50±134.64/field;P<0.05). Also neovascularization of arterioles in the peri-infact zone was significantlyinduced in the experimental group (112.67±12.31/field) and the positive control group(105.83±10.25/field) than other groups (the blank control group:36.17±9.79/field and thenegative control group:51.83±11.89/field; P<0.05). And the LVEF (%) of the experimentgroup (76.104±5.63) and the positive control group (79.106±5.72) was significantly higherthan other groups (the blank control group:62.755±4.88and the negative control group:61.591±4.19; P<0.05). Further analysis by Masson’s Trichrome staining, we found that theratio (%) of fibrosis area after myocardial infarction in experimental group (10.50±6.16)and the positive control group (8.91±2.99) was significantly lower than other groups (theblank control group:36.08±17.91and the negative control group:36.08±17.91; P<0.05).And the ratio (%) of fibrosis length after myocardial infarction in experimental group(18.58±1.72) and the positive control group (21.30±3.87) was significantly lower thanother groups (the blank control group:39.93±13.15and the negative control group:57.12±14.25; P<0.05). The positive group had relatively lower effect than the experimentgroup in vitro and in vivo, but there was no significant difference.Conclusion: Exosomes from BMSCs could promote angiogenesis in matrigeltube-formation assay in vitro. Furthermore, exosomes from BMSCs could promoteneovascularization and inhibit fibrosis in the peri-infarct zone, and dramatically enhanceLV function. |
