Effect of Pre‐Conditioning with Copolymer‐Based Cell Membrane Stabilizer Poloxamer 188 on Adult Mouse Coronary Artery Endothelial Layer Integrity after Prolonged Hypoxia/Reoxygenation

Abstract

Prolonged ischemia followed by reperfusion can cause significant tissue damage and cell death. This ischemia/reperfusion (IR) injury can be alleviated by administration of Copolymer‐based Cell Membrane Stabilizers (CCMS), like the tri‐block Poloxamer (P)188, thought to be able to seal gaps in cell membranes and/or tight junctions and, thus, repair leaks attributable to severe cellular stress. We have previously tested post‐conditioning, i.e. the administration of P188 upon reperfusion/reoxygenation, to attenuate IR injury in various models. Here, we hypothesized that pre‐conditioning, i.e. its administration before simulated ischemia (hypoxia), has a protective effect on endothelial cell layer integrity as assessed by Trans‐Endothelial Electrical Resistance (TEER).Confluent adult mouse coronary artery endothelial cell (ECs) layers were pre‐treated with 0, 30, 100, 300, 1,000, or 2,000 µM P188 during plating of cells before simulated IR with a 24‐hour hypoxic followed by a 2‐hour reoxygenation (HR) period. EC monolayer barrier integrity was assessed by TEER.In contrast to mere post‐conditioning, pre‐conditioning dose‐dependently attenuated HR injury compared to control/normoxia (Fig 1) even after prolonged HR for 24+2 hrs.These results suggest that CCMS may indeed elicit its cardioprotective effect, in part, through protection of the EC layer. However, more research is needed to determine optimal dosage and timing for CCMS administration.