Abstract： Objective:To explore the effects of hyperbaric oxygen combined with bone marrow mesenchymal stem cells（BMSCs）transplantation on the expression of protein kinase R-like endoplasmic reticulum kinase（PERK），inflammatory factors，and oxidative stress-related indicators in rats with spinal cord injury（SCI）.Methods:A total of thirty Sprague Dawley male rats were selected as the research objects. SCI models were established and divided into model group，BMSCs group，and HBO combined with BMSCs group（BMSCs+HBO group）according to the random number table method，with 10 rats in each group. The changes of PERK expression，inflammatory factors，and stress indicators at each time points（at 12 h after SCI injury，and 1，3，7，and 14 d after SCI injury）in the three groups were observed.Results:Compared with the model group，the PERK protein levels of the rats in the BMSCs group and the BMSCs+HBO group were decreased，and the decrease in the BMSCs+HBO group was significantly greater than that in the BMSCs group（ P<0.05）. Compared with the model group，the serum levels of TNF-α，IL-6，and IL-10 in the BMSCs group and the BMSCs+HBO group were decreased，and the decrease in the BMSCs+HBO group was significantly greater than that in the BMSCs group，and the difference was statistically significant（ P<0.05）. On day 7 after SCI injury，the serum MDA level in the BMSCs+HBO group was significantly lower than that in the BMSCs group，and the difference was statistically significant（ P<0.05）. The serum SOD level in the BMSCs+HBO group was significantly higher than those in the BMSCs group on day 3，7，and 14 after injury，and the differences were statistically significant（ P<0.05）. Conclusion:The expression of PERK is active in SCI rats，and the level of inflammatory factors is increased. HBO combined with BMSCs can effectively inhibit the expression of PERK，reduce the level of inflammatory factors，improve oxidative stress indicators，thus promoting spinal cord repair.