Gross and histopathological effects of dimethyl sulfoxide on wound healing in rats

Dimethyl sulfoxide (DMSO) is one of the commonly used vehicles to dissolve water insoluble drugs, including used for wound healing purposes, for different experiments. The present study was aimed to investigate the gross effects and histopathological changes produced by topical DMSO on granulation tissue at wound site. Open excision cutaneous wounds were created on the back of ten male rats and equally divided into two groups. Distilled water and DMSO (10 %) were topically applied once daily for 21 days on wounds of Group I (control group) and Group II, respectively. Grossly, wounds revealed that DMSO facilitated wound closure on day 7 and 12. On day 21, the wound was still not closed in DMSO treated group in comparison to control group. The H & E stained sections of control group showed formation of complete, immature and thin epithelial layer, collagen deposition and infiltration of abundant number of mononuclear cells. Sections of DMSO treated group showed blood vessels, scattered infiltration of inflammatory cells, collagen fibers and partially formed epithelial layer. Semi-quantitative score for inflammatory cells and epithelialization was significantly lower in DMSO treated group. Picrosirius red stained sections showed dominance of orange-red (thicker) collagen fibers in control group and yellow-green (thinner) collagen fibers in DMSO treated group. DMSO treated group showed higher and lower thin collagen and thick collagen fiber fraction, respectively in comparison to control group. Thus, it might be concluded that DMSO facilitates wound closure during the early stages and delays the wound closure during at later stages of wound healing.