[The empirical study on paracrine communication of bone marrow mesenchymal stem cells]

To study the influence of (60)Co gamma exposure on paracrine effect of marrow mesenchymal stem cells (MSC). To evaluate the function and construction after early stage of acute myocardial infarction (AMI) by injection of supernatant liquid. To discuss the mechanism of prarcrine communication initially.

MSC were radiated by (60)Co gamma with different dosage. The culture solution was collected peri-irradiation. The changes of Vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), Interleuki-1beta (IL-1beta) in supernatant liquid were checked by ELISA. Using a rat model of AMI, the supernatant liquid and control medium were injected intramyocardially and intraperitoneally according to the project. After 4 weeks, the cardiac dimension and functions were assessed, the microvessel density were detected.

Three cytokines decreased significantly after irradiation, with the increasing in dosage of irradiation, the secretory volume of cytokines decreased greatly. When compared with the control group (group A 6.6 +/- 0.6) and medium group (group C 5.7 +/- 0.7), the microvessel density in supernatant liquid group (group B 10.8 +/- 2.9) increased obviously, contributing to improvement in cardiac function and dimension. (Left ventricular internal dimension in diastolic (LVDd) postoperation: A 8.1 mm +/- 1.5 mm, B 7.0 mm +/- 1.5 mm, C 7.7 mm +/- 1.1 mm; Eject fraction (EF) postoperation: A 43.8% +/- 8.9%, B 51.5% +/- 7.8%, C 45.6% +/- 8.1%.

(60)Co gamma radiation exposure can degrade MSC' ability of paracrine communication. The paracrine effect which should take important role in improving the cardiac function after AMI. The mechanism of prarcrine is complex, neovascularization is the important link.