Does selective beta-1 blockade provide bone marrow protection after trauma/hemorrhagic shock?

Previously, nonselective beta-blockade (BB) with propranolol demonstrated protection of the bone marrow (BM) after trauma and hemorrhagic shock (HS). Because selective beta-1 blockers are used commonly for their cardiac protection, the

After trauma and HS, protection of BM for 7 days was seen with use of either a selective beta-2 or beta-3 blocker. Use of a selective beta-1 blocker was ineffective in protecting the BM despite a physiologic decrease in heart rate. Therefore, the protection of BM is via the beta-2 and beta-3 receptors and it is not via a direct cardiovascular effect.

Male Sprague-Dawley rats underwent unilateral lung contusion (LC) followed by HS for 45 minutes. After resuscitation, animals were injected with a selective beta-blocker, atenolol (B1B), butoxamine (B2B), or SR59230A (B3B). Animals were killed at 3 hours or 7 days. Heart rate and blood pressure were measured throughout the study period. BM cellularity, growth of hematopoietic progenitor cells (HPCs) in BM, and hemoglobin levels (Hb) were assessed.

Treatment with a B2B or B3B after LCHS restored both BM cellularity and BM HPC colony growth at 3 hours and 7 days. In contrast, treatment with a B1B had no effect on BM cellularity or HPC growth but did decrease heart effectively rate throughout the study. Treatment with a B3B after LCHS increased Hb as compared with LCHS alone.