Carnosine, histidine, and wound healing.

The relationships among carnosine, histidine, and wound healing were examined in rats fed either 100% or 50% of the reported histidine required for growth. Animals fed the adequate amount of histidine grew more rapidly and more efficiently than did animals on the low-histidine diet. When the rats reached the experimental weight range of 165 to 180 gm, they were anesthetized and wounded with back skin incision; a polyvinylchloride sponge was implanted under the skin before closure of the wound. Seven days after wounding, the histidine-sufficient animals had greater regenerative skin-breaking strength, collagen deposition, and tissue concentrations of free histidine and carnosine. Histidine and carnosine treatment (1 mg/100 gm body weight/day intraperitoneally) for 7 days after wounding increased tissue free-histidine concentrations and brought skin-breaking strength and collagen deposition up to "normal" in the animals on the low-histidine diet but did not further improve healing in the histidine-sufficient animals. Treatment with carnosine was similar, but slightly better than treatment with histidine. The results suggest an interaction between carnosine and stress and implicate carnosine as a histidine reserve in relation to histamine synthesis during trauma.