Abstract: Ren Jizhen, Chen Zhenyu, Yang Ting, Wan Jin′e, Zhao Ming. Affiliated Hospital of Qingdao University, Qingdao 266003, China Corresponding author: Chen Zhenyu, Email: czy.plastic@126.com 【Abstract】 Objective To evaluate the effects of hyperbaric oxygen on the expressions of hypoxia-inducible factor 1α （HIF-1α） and insulin-like growth factor-1 receptor （IGF-1R） in the formation of hyperplastic scar in rabbit ears. Methods The ears of 20 New Zealand rabbits were used to construct an animal model for hyperplastic scar by operation. After the establishment of scar models, the rabbits were randomly divided into 4 experimental groups and one control group with 4 mice （48 wound surfaces） in each group. The mice in the 4 experimental groups were treated with hyperbaric oxygen for 7, 14, 21 and 28 days, respectively, and those in the control group remained in normoxic environment after operation. Scar tissues were resected from all the rabbit ears on day 29 after operation. Hematoxylin and eosin （HE） staining was conducted for the observation of morphological changes and calculation of scar elevation index, and immunohistochemistry to measure the expressions of HIF-1α and IGF-1R. Statistical analysis was carried out by one-way analysis of variance followed by least significant difference t-test. Results HE staining showed that both the number of fibroblasts and amount of collagen fibers were significantly reduced in the experimental groups compared with the control group. Scar elevation index was 4.28 ± 0.22 in the control group, 3.64 ± 0.29, 3.46 ± 0.21, 3.29 ± 0.21, 3.16 ± 0.15 in the 7-, 14-, 21- and 28-day experimental groups respectively, with significant differences among these groups （F = 77.70, P < 0.05）. The expressions of HIF-1α and IGF-1R were significantly lower in these experimental groups than in the control group （all P < 0.01）, lower in the 14-day group than in the 7-day group （P < 0.05）, and lower in the 21-day group than in the 14-day group （P < 0.05）, with no significant differences between the 28-day group and 21-day group （both P > 0.05）. Conclusion Hyperbaric oxygen can effectively down-regulate the expressions of HIF-1α and IGF-1R in scar tissue, and significantly inhibit the formation of hyperplastic scar in rabbit ears.

Key words: Hyperbaric oxygenation, Cicatrix, Hypoxia-inducible factor 1 alpha subunit, Receptor, IGF type 1