STRIATED-MUSCLE MICROVASCULAR RESPONSE TO ZYMOSAN-INDUCED GENERALIZEDINFLAMMATION IN AWAKE HAMSTERS

The effect of zymosan-induced generalized inflammation on the microcir culation of distant striated skin muscle was studied for a 12 day peri od in awake Syrian golden hamsters (n = 18) using the dorsal skinfold chamber model and intravital fluorescence microscopy. Intraperitoneal zymosan exposure (125 mg/100 g body weight) induced significant nutrit ive perfusion failure in the distant striated muscle tissue at Day 1 w ithout complete recovery over the 12 day observation period, as indica ted by the marked reduction of functional capillary density when compa red with both baseline Values and values of sham-treated control anima ls. Moreover, intraperitoneal zymosan exposure induced endothelial dis integration, as demonstrated by the continuous increase of macromolecu lar leakage throughout the 12 days of observation. Strikingly, zymosan did not induce significant leukocyte adherence to the endothelial lin ing of postcapillary and collecting venules of the striated muscle tis sue. Thus, we conclude that in this model of generalized inflammation nutritive perfusion failure and loss of endothelial integrity in dista nt striated muscle is not mediated by activated leukocytes, but must r ather be attributed to direct toxic effects of mediators, elicited by the local (intraperitoneal) zymosan challenge and systemically release d.