Expressions of SP and NO/NOS during wound healing and their possible roles

Objective To explore the roles of substance P secreted from periphery nerve endings and nitric oxide (NO) /nitric oxide synthase (NOS) during wound healing and their possible relationship. Methods A total of 50 Wistar rats were randomly divided into 2 groups: the experiment group and the control group. In the experiment group, a whole depth skin on the back of the rats was cut off to make a wound, and the tissues of wound edge and granulation tissues were taken at 1, 3, 6, 9, and 12 d after injury, respectively. In the control group, capsaicin was injected subcutaneously into the skin on the back of the rats to destroy the sensory nerve to prevent the secretion of SP, and then the same method as used in the experiment group was employed. The expression of SP in the granulation tissues was detected by immunohistochemistry. NO and NOS were also detected. Results The wound of rats in the experiment group was healed more rapidly than that in the control group. In the experiment group, immunohistochemical staining of SP was located on the hair follicles and sebaceous glands at 1 d, but the staining of SP was obvious at 3 d in the granulation tissues, and then decreased gradually; NO/NOS levels increased from a relatively low level from 1 d after injury and reached the peak at 6 d, and then decreased obviously. In the control group, however,immunohistochemical staining of SP was faint without obvious change, and NO/NOS levels showed the same tendencyduring the wound healing process. Conclusion During wound healing, SP and NO/NOS may promote the healingprocess, and the role of SP may be attained partly by stimulation of the production of NO/NOS.