Abstract:

Cao Wei *, Chen Lei, Wu Yiping, Feng Youping, Huang Li. *Department of Plastic and Aesthetic Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China Corresponding author: Huang Li, Email: hli1212@163.com 【Abstract】 Objective To evaluate the effects of long-term high-fat diet on skin wound repair in mice, and to explore its related mechanism. Methods A total of 16 ten-week-old C57BL/6J wild-type mice were randomly and equally divided into two groups to be fed a high-fat diet （HFD group） and a standard diet （SD group） respectively for 8 weeks. Then, an 8-mm full-thickness skin wound was created on the back of each mouse by using a biopsy punch. The degree of wound healing was observed, wound healing rate and epithelialization level were evaluated every day. The weight of mice was measured before feeding, after 8-week feeding and on day 14 after the operation. Peripheral blood samples were obtained from these mice for the determination of total cholesterol （TC） and triglyceride （TG） levels after a 12-hour fast on day 14 after the operation. Then, all the mice were sacrificed, and wound tissues were resected from the dorsal skin of mice for a histological study. The two-sample t test was used to compare the thickness of new epidermis in the wound surface, collagen deposition rate in the wound bed, count of new vessels, levels of cell proliferation and degree of inflammatory cell infiltration between the two groups. Results The average weight of mice was significantly higher in the HFD group than in the SD group after 8-week feeding （27.3 ± 0.7 g vs. 21.2 ± 0.6 g, t = 21.98, P < 0.001） and on day 14 after the operation （28.8 ± 0.7 g vs. 23.1 ± 1.1 g, t = 25.22, P < 0.001）. Similarly, there was a significant increase in the levels of TC （1.35 ± 0.32 mmol/L vs. 0.99 ± 0.28 mmol/L, t = 2.24, P < 0.05） and TG （4.21 ± 0.41 mmol/L vs. 2.71 ± 0.31 mmol/L, t = 6.49, P < 0.05） in the HFD group compared with the SD group 14 days after the operation. Compared with the SD group, the HFD group showed shorter healing time （13.5 ± 0.5 days vs. 12.6 ± 1.1 days, t = 1.99, P < 0.05）, lower thickness of newborn epidermis on the wound surface （47.8 ± 13.8 μm vs. 95.7 ± 13.7 μm, t = 5.68, P < 0.001）, decreased number of CD31-positive vessels （8 ± 1 vs. 13 ± 3, t = 4.1, P < 0.001） and count of ki-67-positive cells （21 ± 4 vs. 49 ± 10, t = 3.33, P < 0.001）, but increased count of infiltrating macrophages and mast cells （both P < 0.05）. No significant difference was found in collagen deposition rate in the wound bed between the two groups （P > 0.05）. Conclusion Long-term high-fat diet can affect wound healing and delay skin wound repair in mice.