Abstract： Objective:To study the efficacy and mechanism of hyperbaric oxygen therapy on peripheral circulation disorder and foot ulcer in diabetic rats.Methods:A total of sixty adult healthy male SD rats were selected and randomly divided into non-diabetic group，diabetic sham treatment group，and hyperbaric oxygen treatment group，with 20 rats in each group. The diabetic model was established by injecting 2% streptozotocin，and the model of foot ulcer model was established by continuous scalding the rat’s left posterior sole with steam（with an area of about 37 mm 2）. An infrared thermometer was used to measure the temperature of the rats’ two posterior soles，and a plantar tester was used to measure the rats’ plantar thermal pain thresholds. The plantar temperatures and plantar thermal pain thresholds of the rats in the three groups were compared before treatment and after 1 week，2 weeks，and 4 weeks of treatment. The levels of cyclooxygenase 2（COX-2），vascular endothelial growth factor（VEGF），serum tumor necrosis factor-α（TNF-α），interleukin-1β（IL-1β），interleukin- 6（IL-6），hypersensitive C-reactive protein（hs-CRP），malondialdehyde（MDA），superoxide dismutase（SOD），and catalase（CAT）in wound tissue were detected. Results:Before treatment，the plantar temperatures of the rats in the diabetic sham treatment group and the hyperbaric oxygen treatment group were lower than that in the non-diabetic group（ P<0.05）；there was no significant difference in the plantar temperature within each group before and after treatment（ P>0.05）. After 1 week of treatment，the plantar temperatures of the rats in the diabetic sham treatment group and the hyperbaric oxygen treatment group were lower than that in the non-diabetic group（ P<0.05）；after 2 and 4 weeks of treatment，the plantar temperature of the rats in the diabetic sham treatment group was lower than those in the non-diabetic group and the hyperbaric oxygen treatment group（ P<0.05）. Before treatment，the plantar thermal pain thresholds of the rats in the diabetic sham treatment group and the hyperbaric oxygen treatment group were higher than that in the non-diabetic group（ P<0.05）；after 1 week of treatment，the plantar thermal pain threshold of the rats in the hyperbaric oxygen treatment group was lower than that before treatment，and the plantar thermal pain thresholds of the rats in the diabetic sham treatment group and the hyperbaric oxygen treatment group were higher than that in the non-diabetic group（ P<0.05）；after 2 weeks of treatment，the plantar thermal pain thresholds of the rats in the non-diabetic group and the diabetic sham treatment group were lower than that before treatment，and the plantar thermal pain threshold of the rats in the hyperbaric oxygen treatment group was higher than that in the non-diabetic group but lower than that in the diabetic sham treatment group（ P<0.05）. After 4 weeks of treatment，the plantar thermal pain thresholds of the rats in the non-diabetic group and the hyperbaric oxygen treatment group were lower than that before treatment，and the plantar thermal pain threshold of the rats in the diabetic sham group was higher than those in the non-diabetic group and the hyperbaric oxygen treatment group（ P<0.05）. There was no significant difference in wound area among the three groups of rats before treatment（ P>0.05）. After 1 week of treatment，the wound areas in the three groups of rats were significantly increased compared with those before treatment，and the wound areas in the non-diabetic group and the hyperbaric oxygen treatment group were larger than that in the diabetic sham group（ P<0.05）. After 2 weeks and 4 weeks of treatment，the wound areas of the rats in the three groups were significantly reduced compared with those after 1 week of treatment，and the wound area of the rats in the hyperbaric oxygen treatment group was larger than that in the non-diabetic group but smaller than that in the diabetic sham treatment group，with statistically significant differences（ P<0.05）. After treatment，the level of COX-2 in wound tissue of the rats in the hyperbaric oxygen treatment group was lower than that in the diabetic sham treatment group but higher than that in the non-diabetic group（ P<0.05）；the level of VEGF in wound tissue of the rats in the hyperbaric oxygen treatment group was higher than those in the diabetic sham treatment group and the non-diabetic group（ P<0.05）. After treatment，the levels of TNF-α，IL-6，IL-1β，and hs-CRP of the rats in the hyperbaric oxygen treatment group were lower than those of the rats in the diabetic sham treatment group but higher than those in the non-diabetic group（ P<0.05）. After treatment，the levels of SOD，MDA，and CAT of the rats in the hyperbaric oxygen treatment group were lower than those in the non-diabetic group but higher than those in the diabetic sham treatment group（ P<0.05）. Conclusion:Hyperbaric oxygen can improve the plantar temperature and thermal pain threshold of diabetic feet，reduce the level of COX-2，and increase the level of VEGF；meanwhile，it can reduce inflammation and oxidative stress reactions，promote ulcer wound healing，and improve peripheral circulation disorder. Thus it is of good clinical application value.