Effect of splenectomy on acute inflammation.

It is becoming increasingly evident that platelets play a significant role in the inflammatory process. Heterogeneity has been demonstrated among platelets, and evidence has been presented that the spleen retains the youngest and hemostatically most effective platelets. The present study was designed to determine what effect splenectomy, by removing a special population of platelets, would have on acute inflammation as manifested by carrageenan-induced murine foot pad edema. Swiss white mice (25 +/- 2 g) were anesthetized and subjected to splenectomy (Group A, n = 13) or to celiotomy only (Group B, n = 15). One week later, carrageenan (0.1 cc of 1% solution) was injected into the right hind foot pad of each animal. The mice were killed 3.5 hr later, and both hind paws amputated at the tibio-tarsal joint and weighed individually. The change in weight of the experimental hind paw relative to control was expressed as edema index for each animal. The inflammatory reaction, as manifested by carrageenan edema, was significantly (P less than 0.001) decreased in those animals subjected to splenectomy. The mean edema index in Group A was 62.8 per cent compared to 80.9 per cent in Group B. The results of this study indicate that splenectomy decreases inflammation as manifested by carrageenan-induced edema. Splenectomy eliminates a population of platelets having greater functional capabilities than those found in the peripheral circulation and impairs the organism's ability to respond to injury.