Hemodynamic, biochemical and morphological changes in the dextran and D-galactosamine-induced edemas in rats.

Dextran (600 mg/kg i.p.) and D-galactosamine (300 mg/kg s.c.)-induced edemas in the rat have been evaluated and compared on the basis of hemodynamic, biochemical and morphological investigations. The genesis of the edema induced by dextran was quicker (1-3 hr) than that induced by D-galactosamine. The edema index at the levels of the paws was higher in the dextran (10.5 +/- 0.6) than in the D-galactosamine (5.1 +/- 0.4)-induced edema. Furthermore, the dextran-induced edema was associated with marked hypotension and a decrease in the plasma protein levels. Bradycardia, decrease in the cardiac output and the coronary blood flow were observed in both the edemas. Blood flows to the brain, kidneys, lungs, spleen and paws were decreased only in the dextran-induced edema. It was interesting to note that the percentage distribution of the cardiac output in the paws was decreased in the dextran-induced edema only. PGE2 levels were increased, whereas the histamine levels were decreased in the paw-skin in both the edemas. These changes were relatively more marked in the dextran edema. The levels of PGF2 alpha remained unchanged. The above findings have been further supported by our morphological data where relatively more degranulation of the mast cells and that too at a shorter period, was observed in the dextran-induced edema. Different mechanisms for the genesis of these two kinds of edemas have been suggested.