IMMUNE FUNCTION IS MORE COMPROMISED AFTER CLOSED BONE-FRACTURE AND HEMORRHAGIC-SHOCK THAN HEMORRHAGE ALONE

Objective: To determine whether closed bone fracture in conjunction wi th hemorrhagic shock compromises immune functions more severely than h emorrhagic shock alone. Design: In a randomized, controlled trial, clo sed bone fracture of the right lower leg and/or hemorrhagic shock (mea n+/-SEM arterial blood pressure, 35+/-5 mm Hg for 90 minutes) were ind uced in male C3H/HeN mice (weight, 25 g). Animals subjected to hemorrh age were resuscitated with the shed blood and lactated Ringer solution . At 72 hours after the experiment, all animals were killed to obtain whole blood, splenocytes, and splenic and peritoneal. macrophages. Mac rophage interleukin-l and splenocyte interleukin-2 and interleukin-3 r elease were determined by bioassay, and splenocyte proliferation was m easured by tritiated thymidine incorporation. Results: Closed bone fra cture alone did not affect immune functions 72 hours after the trauma. Hemorrhagic shock, however, induced a significant depression of splen ocyte and macrophage functions. Bone fracture followed by hemorrhagic shock further depressed splenocyte proliferation and splenocyte interl eukin-2 and interleukin-3 release as well as interleukin-l release. Co nclusion: Since bone injury coupled with hemorrhagic shock produces mo re severe depression of immune functions than hemorrhage alone, bone i njury appears to play a contributory role in further depressing immune functions in trauma patients who experience major blood loss.