Extravascular platelets in corneal microvascular inflammation: a potential determinant of recovery from wound injury

Abstract

The notion that platelets extravasate across inflamed microvessels is not well appreciated and their functional role is unknown. Recently, we reported evidence of extravascular platelets surrounding inflamed venules in a mouse model of corneal wound injury, and of a functional role for platelets in nerve recovery in this model. Whether extravascular platelets are required for nerve recovery remains unclear. In this study we assessed the relationship between microvascular platelet recruitment (intra vs. extravascular, at 12 h) and nerve recovery (at 96 h) following wound injury. We studied wild type (WT) mice, and mice deficient in either ICAM‐1 or gamma‐delta T cells. Nerve recovery was reduced by ~50% in both strains of deficient mice. Interestingly, the number of intravascular platelets was comparable among all strains, while the number of extravascular platelets was markedly reduced (by > 85%) in mice deficient in ICAM‐1 and gamma‐delta T cells. These data suggest a functional role for extravascular platelets in nerve recovery following corneal injury.Support: NIH EY018239, EY17120, HL079368