[Effects of phosphatidylcholine therapy after hindlimb ischemia and reperfusion]

Microcirculatory dysfunctions and mast cell reactions play important roles in hypoxic tissue injuries. The aims of this study were to characterize the effects of hindlimb ischemia-reperfusion on the periosteal microcirculation and to define the consequences of systemic phosphatidylcholine therapy during this condition.

Microcirculatory changes were visualized by means of fluorescence intravital videomicroscopy in anesthetized Wistar rats. 60 min of complete hindlimb ischemia was followed by a 180-min reperfusion in the presence of phosphatidylcholine treatment (50 mg/kg iv; in the second 10 min of reperfusion) or vehicle. Further two groups served as vehicle- or PC-treated sham-operated controls. The proportion of degranulated mast cells and the leukocyte accumulation (myeloperoxidase, MPO assay) were determined in muscle biopsies.

Ischemia-reperfusion significantly increased the muscle MPO activity (from 14.94 to 63.45 mU/mg) and the proportion of degranulated mast cells (to 82.5%). The periosteal capillary red blood cell velocity (RBCV) and the functional capillary density (FCD) had decreased, while the primary and secondary leukocyte-endothelial cell interactions had increased by the end of reperfusion (rolling from 20.8 to 40.0%, and firm adherence from 254 to 872 mm-2). Phosphatidylcholine treatment decreased the leukocyte rolling and sticking, preserved the FCD and improved the RBCV The mast cell degranulation and MPO activity diminished significantly in the muscle layer.

Mast cell degranulation accompanies ischemia-reperfusion-induced periosteal microcirculatory derangement. Systemic phosphatidylcholine treatment affords protection through ameliorating secondary inflammatory reactions.