Wound healing in rat skin subjected to loud noise stress; a light microscopic study.

Objective: To determine the effect of loud noise stress on wound healing in a skin tissue.

Methods: The randomised control trial was conducted at the Department of Anatomy, College of Physicians and Surgeons Pakistan Regional Centre, Islamabad, from September 2007 to September 2008. The study comprised 240 male Sprague Dawley rats who were randomised into control group A and experimental group B. Each group comprised 120 animals. Main groups were further subdivided into four subgroups of 30 animals each. After induction of local anaesthesia a linear full thickness skin incision paravertebral to thoracic spine was made. The experimental group B was exposed to loud noise stimulus. The animals were decapitated 1, 3, 5 and 7 days after surgery. Histological data was collected in the incisional space of the wound. Polymorpho-nuclear leukocytes, macrophages, fibroblasts and blood vessels, were analysed quantitatively, whereas re-epithelialisation and content of collagen fibres in the incisional space were analysed qualitatively.

Results: Macrophages were decreased initially 3 days after surgery and were increased 5 and 7 days after surgery in the experimental subgroups. Similarly, blood vessels and fibroblast were significantly decreased in experimental subgroups 3 days after surgery, but were increased significantly in experimental subgroups 7 days after surgery. Nothing significant was found regarding re-epithlialisation and collagenisation of wound.

Conclusion: Loud noise stress affects the important cells involved in the healing of the wound. Therefore, it is expected to have an impact on the stages of wound healing.