Efficient Isolation and Phenotypic Characterization of Primary Rat Pulmonary Pericytes

Pericytes are essential regulators of pulmonary vascular homeostasis, but their isolation from rat lung tissue is challenging because no single marker uniquely identifies them and contaminating fibroblasts, endothelial cells, hematopoietic cells, and vascular smooth muscle cells can persist during isolation and culture. Here, we describe a rapid and efficient protocol for the isolation of primary rat pulmonary pericytes using sequential magnetic depletion of CD45-positive hematopoietic cells and CD31-positive endothelial cells, followed by positive selection for NG2-positive cells. The isolated cells were expanded in culture and characterized by immunofluorescence and functional co-culture assays. Cultured cells displayed typical pericyte morphology and expressed the pericyte-associated markers NG2, PDGFR{beta}, and 3G5, with minimal expression of CD31, CD45, PDGFR and MYH11. In endothelial cell-pericyte ECM gel co-culture assays, isolated pericytes associated with endothelial cords and were frequently observed near network branch points and junctions, further supporting their pericyte identity. This method yields an enriched population of primary pulmonary pericytes suitable for downstream applications, including cell culture and functional studies. Overall, this streamlined protocol provides a practical platform for studying pulmonary pericyte biology in rat models of health and vascular disease.