Application of exogenous substance P in wound healing of skin injury in diabetic rat

Objective To study the effects of substance P(SP) on improving the wound healing of skin injury in diabetic rat.Methods Forty-eight diabetic rats,each rat had two round-shaped-wounds through the whole skin by the side of the spine on the back.The rats were divided into two groups: control group and experimental group,each group consisted of 24 rats.200μl of substance P,10-7each wound,was injected around each wound of the experimental group,two times a day.While the same volume of normal saline was injected in the same site to the control group.The area of the wounds was measured at different time.The content of hydroxyproline was measured at the same time.The changes of the collagen type I and collagen Ⅲ were estimated by immunohistochemical staining.The healing time was recorded after wounding.Results The wound area decreased obviously in the experimental group as compared with control group on the 4th,7th,10th,14th day after injury(P0.01).The healing time shortened in the experimental group as compared with the control group.The content of hydroxyproline within granulation tissue increased on the 4th,7th,10th day.The same changes with the collagen type Ⅰ and collagen Ⅲ(P0.01) were found.Conclusion The healing of the wound on the back of diabetic rat was improved by substance P.