NEW SKELETAL-MUSCLE MODEL FOR THE LONGITUDINAL-STUDY OF ALTERATIONS IN MICROCIRCULATION FOLLOWING CONTUSION AND CRYOTHERAPY

This preliminary report describes the use of a rat model developed to study in vivo the effect of anesthesia, contusion, and cryotherapy on skeletal muscle microcirculation by use of an implanted chamber. The d iameters of arterioles and venules within the chamber were determined by photomicroscopy in the contusion study and by compound videomicrosc opy in the anesthesia study; microvascular perfusion was determined by laser Doppler fluxmetry (LDF). Combined ketamine and xylazine anesthe sia significantly reduced (P < 0.05) arteriolar and venular diameters by 32.4% and 37.8%, respectively, and average LDF measurements by 36.1 %. Contusion significantly increased arteriolar diameters over baselin e values (P < 0.05); cryotherapy did not alter arteriolar diameters bu t increased venular diameters (P < 0.05). It is hypothesized that this increase in venular diameter may, by increasing the surface area avai lable for reabsorption, explain one mechanism by which cryotherapy dec reases the edema of contusion. Use of this model should help to advanc e the understanding of microcirculatory dynamics following contusion a nd cryotherapy. (C) 1993 Wiley-Liss, Inc.