AMPK Activation by Ozone Therapy Inhibits Tissue Factor-Triggered Intestinal Ischemia and Ameliorates Chemotherapeutic Enteritis

Background and Aims: Chemotherapeutic enteritis is a major dose-limiting adverse reaction to chemotherapy, and few effective drugs are currently available in clinic. Recently the mechanism of intestinal ischemic injury has emerged in the research spotlight due to its notable influence on chemotherapeutic enteritis, but the pathological mechanism of ischemic injury remains unclear. Methods: Irinotecan (CPT-11) was used to establish chemotherapeutic enteritis animal model. Western blotting, gelatin zymography, immunohistochemistry (IHC), intestinal blood flow measurement were used to detect the pathogenesis of ischemia-hypoxia injury. In clinic, the effects of ozone treatment and coagulation examination in patients with chemotherapeutic enteritis were recorded. Results: CPT-11 increased levels of tissue factor (TF) both in the blood and in intestines in mice. Interestingly, the elevation of TF in the blood displayed "double-peak", which was consistent with the intestinal mucosal "double-strike" injury trend. CPT-11 decreased the intestinal blood flow. Moreover, we found that ozone therapy could relieve chemotherapeutic enteritis in mice. We also found that ozone autotransfusion therapy could effectively attenuate chemotherapeutic enteritis and the blood hypercoagulability in cancer patients. Ozone therapy could inhibit TF expression induced by CPT-11 and effectively ameliorate the intestinal mucosal injury in mice. Further research showed that ozone could activate AMPK/SOCS3 to inhibit TLR-4/p38/TF signaling pathway. Conclusions: For the first time, we proposed that TF-induced thrombotic intestinal ischemic injury is a core trigger pathological mechanism of chemotherapeutic enteritis, and provided a new treatment strategy, ozone therapy, to suppress TF expression and treat chemotherapeutic enteritis. Funding Statement: This work was supported by grants from Major Science and Technology Innovation Project of Shandong Province (2018CXGC1220), Major Project of "Science and Technology Innovation Fund" of Nanjing Medical University (2017NJMUCX004), the Natural Science Foundation of Jiangsu province (BK20161033), the Natural Science Foundation of Jiangsu province (BK20181363). Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: All participants provided written informed consent for participation in the study. This study was approved (2017S053) by the internal review board of the Ethics Committee of Shandong Provincial Qianfoshan Hospital. Animal care and husbandry were carried out in strict accordance with the recommendations of the Guide for the Care and Use of Laboratory Animals (Ministry of Science and Technology of China, 2006) and the Nanjing Medical University Animal Care and Use Committee (NMJU-ACUC). Our study protocol was approved by the NMJU-ACUC, and efforts were made to minimize animal suffering and to reduce the number of mice used.