Acute propranolol infusion stimulates protein synthesis in rabbit skin wound

BACKGROUND: Propranolol administration has been demonstrated to improve cardiac work, decrease energy expenditure, and attenuate lipolysis in burned patients; however, its effect on wound healing has not been reported. METHODS: In rabbits, a partial-thickness skin donor site wound was created on the back, and catheters were placed in the carotid artery and jugular vein. A nasogastric feeding tube was placed for enteral feeding. On day 5 after injury, stable isotope tracers were infused to determine protein and DNA kinetics in the wound. Propranolol hydrochloride was injected in 1 group during the tracer infusion to decrease heart rate, and the other group without propranolol injection served as a control. RESULTS: The propranolol infusion decreased heart rate by 21%. The protein fractional synthetic rate in the wound was greater in the propranolol group (8.6 +/- 0.9 vs 6.1 +/- 0.5%/day, P < .05). Wound protein fractional breakdown rates were not significantly different. The rate of protein deposition (synthesis - breakdown) was increased in the propranolol group (5.0 +/- 1.2 vs 2.8 +/- 0.7%/day, P = .07). Wound DNA fractional synthetic rates were comparable. The protein fractional synthetic rate was correlated with percent decrease in heart rate, but expression of the beta-adrenergic receptors and downstream signaling cascades in local wounds were not affected after propranolol treatment. CONCLUSION: Propranolol infusion increased wound protein synthetic rate and tended to increase wound protein deposition rate, which might be beneficial to wound healing. These changes might reflect a systemic response to the beta-adrenergic blockade.