Abstract
Expression levels of miR-223-3p and NLRP3 in high glucose and high fat (HGHF)-induced diabetic mice, and the mechanism on the injury of mouse cardiac microvascular endothelial cells (MCMECs) were investigated. Four-week C57BL/6J laboratory mice were selected and randomized into a control group and a model group (n=10 each). Mice in the model group were fed with HGHF diet to establish a mouse model of diabetes. Further MCMECs were purchased to construct carriers through transient transfection, and were separated into a normal group (cultured in the normal environment), a model group (not transfected), a blank carrier group (transfected with miR-NC), a miR-223-3p-mimics group, and a miR-223-3p-inhibitor group. RT-qPCR was used to detect the expression levels of miR-223-3p and NLRP3, and western blot analysis to detect the expression levels of NLRP3, apoptosis-related proteins Bax and caspase-3, and anti-apoptotic protein Bcl-2. Flow cytometry was used to observe apoptosis and TargetScan to predict the target relationship between miR-223-3p and NLRP3. Dual-luciferase reporter gene assay was used to detect the relationship between miR-223-3p and NLRP3. Compared with those in the control group, the mice in the model group had significantly lower expression of miR-223-3p. However, significantly higher mRNA and protein expression levels of NLRP3 were observed (P<0.05). After modeling, miR-223-3p overexpression downregulated the expression levels of NLRP3 mRNA, Bax and NLRP3 protein, as well as inhibited endothelial cell apoptosis (P<0.05), while the inhibition of miR-223-3p expression upregulated the expression levels and promoted apoptosis. In conclusion, miR-223-3p expression is low, however, NLRP3 is highly expressed in the heart tissue of HGHF-induced diabetic mice. miR-223-3p reduces the injury of MCMECs and inhibits endothelial cell apoptosis in mice by regulating the expression of NLRP3.