Abstract:Objective: To establish a vascular endothelial-specific overexpressed microRNA-155 transgenic rat model; and to observe its blood pressure, proteinuria phenotypes and changes after gestational load application. Methods: The exogenous miR-155 gene was inserted downstream of the VE-cadherin promoter specifical for vascular endothelial cells to construct the transgenic expression vector. After linearization of the vector, the miR-155 transgenic rats were established by zygote microinjection technique. The genotype of transgenic rats was identified by specifical primer PCR. Furthermore, tail-cuff method, biochemical detection and histological examination were used to preliminarily analyze the phenotypes of pregnant and non-pregnant female transgenic rats. Results: The miR-155 expressions in thoracic aorta, abdominal aorta, kidney and heart tissues of the vascular endothelial-specific overexpressed microRNA-155 transgenic rats were 2.3-fold, 3.3-fold, 2.9-fold and 3.3-fold higher than the wild-type rats,respectively. No significant differences were observed in blood pressure, urine protein, vascular wall or kidney structure between the miR-155 transgenic non-pregnant female rats and the non-transgenic rats. However, after pregnancy, the miR-155 transgenic female rats exhibited mildly elevated blood pressure, increased proteinuria, increased incidence of fetal growth restriction, disorderly structure of thoracic/abdominal aortic walls, tubular epithelial vacuolization, etc. Conclusion: After increase of gestational load, the vascular endothelium-specific miR-155 transgenic rats exhibited pre-eclampsia phenotype.