Isolation and culture of rat intestinal mucosal microvascular endothelial cells using immunomagnetic beads

Microvascular endothelial cells (MVECs) have been an important tool in many research fields, while their purification remained challenging, particularly from thin and fragile tissues, such as murine intestinal mucosae. Therefore, we established an immunomagnetic method for isolating rat intestinal mucosal MVECs using an automatic magnetic separation system from the primary cell culture, which was preliminarily purified by the differential adhesion combined with mechanically scraping method. The CD31+ cells were separated and their purity was about 96.5%, which grew into a contact-inhibited cobblestone-like monolayer after about 6-day incubation. Transmission electron microscopy analysis showed the presence of Weibel-Palade bodies. The endothelial tubes formed on Matrigel for about 4-h cultivation. The MVECs could grow well until at least passage 10. Immunofluorescence staining indicated that factor VIII (FVIII), CD31 and CD34 were generally expressed in the MVECs. The fluorescence intensity of FVIII was higher after magnetic separation than before, while those of CD31 and CD34 didn't have significant difference. In conclusion, highly pure MVECs were isolated from rat intestinal mucosae using magnetic beads coated with anti-CD31 antibodies, and magnetic separation may influence the expression of FVIII.