Effect of low- and high-dose methotrexate on wound healing in rats

Purpose: To investigate the effect of intraperitoneal treatment with low- and high-dose methotrexate (MTX) on wound healing in rats. Methods: The study sample consisted of 54 healthy rats. Under aseptic conditions, skin wounds were created with two circular fullthickness punch tools, 10 mm in diameter, one on the right and the other one on the left of the dorsal vertebral line. The rats were randomly assigned to one of three main treatment groups. On the 0th day (2 hours before wound creation), 7th day, and 14th day, the control group received 0.3-mL saline, the low-MTX group received 3 mg/kg MTX, and the high-MTX group received 30 mg/kg MTX, all administered intraperitoneally. The wounds were evaluated seven, 14, and 21 days after injury through morphometrical, biochemical, histopathological, and immunohistochemical analyses. Results: MTX dose-dependently decreased the degree of inflammation and angiogenesis, tissue hydroxyproline level, and HSP70 and tumor necrosis factor-alpha expression in the early phase of wound healing. It also suppressed epithelialization and collagen 1 expression throughout the wound-healing process. Conclusion: The wounds treated with high-dose of MTX had statistically delayed wound closure on days 7, 14 and 21 compared to the saline group, while wounds treated with low-dose of MTX only had statistically delayed wound closure on day 14. In addition, weight loss was observed in rats treated with high-dose MTX, which was thought to reflect its toxicity. The dose-dependent adverse effect of MTX on wound healing may be due to its antiproliferative, antifibrotic, anti-inflammatory, and antiangiogenic effects.