Bone marrow failure after hemorrhagic shock

The proliferation of white blood cells is an important and necessary response to bacterial infection. The effect of hemorrhagic shock and LPS administration on myelopoiesis was investigated. Rats subjected to hemorrhagic shock and resuscitation were injected IP with 100 micrograms E. coli LPS or saline 24 hr following shock. Twenty-four hours later, myelopoiesis was assessed by the growth of granulocyte-macrophage progenitor cells (CFU-GM) in both bone marrow (BM) and spleen (SPL). CFU-GM were cultured in the presence of no additional serum or normal rat serum or shock serum obtained 6 hr after hemorrhage. Shock resulted in a peripheral leukocytosis although BM and SPL cellularity was unaffected by either shock or LPS. BM and SPL CFU-GM from unshocked rats significantly increased after LPS administration (BM 47 +/- 6 vs. 70 +/- 8; SPL 40 +/- 4 vs. 72 +/- 14; both P less than 0.05). Shock had no effect on BM or SPL CFU-GM. In contrast, LPS given to shocked rats decreased BM CFU-GM compared to saline-treated rats (50 +/- 3 vs. 34 +/- 4 P less than 0.05). The addition of normal serum to the culture system had no effect on BM CFU-GM but the addition of shock serum reduced CFU-GM by 50% in all groups (P less than 0.05). These data demonstrate that shock markedly alters the myelopoietic response to LPS and may also result in the production or release of inhibitors of CFU-GM growth.