Microvascular Response to Shock Wave Application in Striated Skin Muscle

Background. This study aims to quantify by intravital microscopy the microhemodynamic response after extracorporeal shock wave application (ESWA) to the physiologic microcirculation of the mouse dorsal skinfold chamber. Materials and Methods. ESWA was carried out using an electrohydraulic shock wave source. Two different shock wave doses of 500 and 1000 pulses at an energy flux rate of 0.08 mJ/mm(2) and a frequency of 4 Hz were compared with sham-operated animals. Microcirculatory analyses were performed at baseline (BL) and during a 3 d observation period after ESWA. The expression of caspase-3 (casp-3), proliferating cell nuclear antibody (PCNA), von Willebrand factor (vWF), and endothelial nitric oxide synthase (eNOS) were analyzed semiquantitatively by immunohistochemistry. Results. ESWA provoked a significant and persistent increase of functional capillary density (FCD) throughout the observation period, reaching a maximum(140% +/- 5% of BL, P < 0.05 versus sham) after 1 d when animals were treated with 1000 pulses. ESWA induced a slight increase of leukocyte rolling (similar to 2- to similar to 3.5-fold, P < 0.05) and leukocyte adherence (similar to 1.5- to similar to 2-fold, P < 0.05) to the endothelial lining of postcapillary venules. One day following ESWA, we observed enhanced expression of casp-3 (similar to 3- to similar to 4-fold), PCNA (similar to 9- to similar to 14-fold), vWF (similar to 11- to similar to 14-fold), and eNOS (similar to 3-fold), all P < 0.05. Conclusion. This study shows that ESWA provokes a favorable persistent increase of patent capillaries, however accompanied by a transient and slight inflammatory response but also by dose-dependant apoptotic cell death. Our data suggest that ESWA might represent a noninvasive biomechanical tool to treat critically perfused and endangered tissues, but certainly warrants further investigation. (C) 2011 Elsevier Inc. All rights reserved.