Mast cell mediation of muscle and pulmonary injury following hindlimb ischemia-reperfusion

We have observed extensive mast cell degranulation in the reperfused hindlimb muscle of the mouse, accompanied by pathological changes within the muscle. As quantitated by the tissue:blood I-125 permeability ratio, both the hindlimbs and lungs exhibited a significant increment in permeability during hindlimb reperfusion. In lungs of the same mice, mast cell-derived chymase mMCP-1 coats alveolar macrophages, an event noted by us in acid-induced direct lung injury. Mast cells in the lung contain mMCP-1, whereas those in the muscle do not. Neither extensive muscle injury nor an increased pulmonary permeability index occurs in the mast cell-deficient W/W-V mice. We conclude that the mast cell is a key mediator in both local ischemia-reperfusion injury (I-R) of muscle and consequent remote lung injury.