Myocardial Microvascular Endothelial Cells Mesenchymal Transition Under Hypoxic Condition And Fluastation Intervention

Background Myocardial fibrosis (MF) was closely related to cardiovascular diseases such as myocardial infarction and high blood pressure. It was the common pathological feature of multi-cardiovascular diseases when developed in a certain period, and was an important prognostic factor of cardiovascular disease. MF could lead to heart failure, arrhythmia, sudden cardiac death and other serious complications. Therefore, inhibiting and reversing MF played a critical role in improving the prognosis of cardioascular diseases. It was one of the key points in clinical treatment. In recent years, some studies showed that vascular endothelial cells could turn into other cell types under certain circumstances, causing MF, and further affecting the function of heart. The mechanism of MF is still unclear, results of some researches showed that transformation growth factor beta 1 (TGF-β1) could promote the transformation and differentiation of endothelial cells to interstitial cells.Objective We aimed to isolate the myocardial microvascular endothelial cells (MMVECs) from the heart of SD rat, and constructed the transformed and differentiated model of MMVECs in hypoxic condition. Then we investigated the affects of fluastatin in the transformation and differentiation of MMVECs in vitro, and determined the critical role of statins in prevention and treatment of MF.Methods The MMVECs was acquired from the heart of SD rats with 3-5 days old using the enzyme digestion method. The two times of differential adhesion method was used to isolate and purify the cells. The MMVECs were identified through the cell morphology and MMVECs specific antigen. The experiment was separated into three groups:A, control group; B, low oxygen group; C, low oxygen + fluastatin group. The cells were cultured for 3 or 7 days respectively. The transdifferentiation of MMVECs into fibroblast was identified by cell morphology and the expression of CD31 and FSP-1 under immunofluorescence microscope. RT-PCR was performed to determine the mRNA level ofα-SMA and FSP-1.Results MMVECs were acquired successfully and consistent with the characteristics of MMVECs identified by CD31 and factorⅧ. We then used the second generation endothelial cells in experiment. The immunofluorescence results showed that a part of cells in B and C group showed a double-staining of CD31 and FSP-1 respectively. The mRNA expression ofα-SMA and FSP-1 were upregulated in group B and C, and the level was higher in group B than that in group C.Conclusions MMVECs transdifferentiated into interstitial cells under hypoxic conditions; fluastatin significantly inhibits this kind of transdifferentiation. Statins may be used in clinic to inhibit MF of patients with cardiovascular diseases.