Effects of depression on collagen levels during wound healing in rats

Objective To measure the collagen content in the granulation tissue of skin wound surface in rats with depression in order to explore the possible mechanism about depression to wound healing.Methods Totally 126 Sprague-Dawley rats were randomly and equally allocated to 3 groups: simple wound group,depression plus wound group,wound plus depression group.Unpredictable stimuli,including fasting,electrocution,water deprivation,swimming in cold water and others,were performed for 18 d to establish depression model of rats.A full-thickness dermal wound(2.2 cm in diameter) was made on the back of rats to build wound model.Rats from depression plus wound group received 18 days' stimuli and then wound cutting.For those of wound plus depression,stimuli were carried out from the next day of wounding.The basal tissue in the center of the wound was taken out from 6 rats of every group in 3,5,7,10,14,18 and 21 d after wounding.Hydroxyproline reagent kit was used to detect the content of hydroxyproline in collected tissue.Wound collagen depositions in every time point were stained by nitroxanthic acid sirius red and then observed by polarization microscopy.Results Hydroxyproline content and collagen deposition in wound granulation tissue of depression plus wound group rats were lower than those in the other 2 groups.From 18 d after wounding,rats of depression plus wound group had a tendency to the same level as wound plus depression group.Conclusion Depression plus wound significantly decreases hydroxyproline synthesis,reduces collagen deposition in wound,and then delays the wound healing.