Ozone water enema activates SIRT1-Nrf2/HO-1 pathway to ameliorate gut dysbiosis in mice receiving COVID-19 patient-derived faecal microbiota

<b>Introduction.</b> This study centres on how coronavirus disease 2019 (COVID-19) disrupts the intestinal microbiota and amplifies systemic inflammation and evaluates ozone water enemas as a strategy to restore gut microbial balance and activate the SIRT1 (silent information regulator of transcription 1)-Nrf2 (nuclear factor erythroid 2-related factor 2)/HO-1 (heme oxygenase-1) pathway for alleviating post-viral sequelae. Our findings demonstrate that ozone water intervention markedly improves the intestinal microenvironment in mice receiving COVID-19 patient-derived microbiota and attenuates systemic inflammation, offering a viable adjunctive approach for COVID-19 management.<b>Hypothesis.</b> Despite significant progress in reducing the incidence of COVID-19, its long-term consequences, including hepatic dysfunction, pulmonary injury and gut microbiota dysbiosis, remain challenging. While ozonated water enema therapy has shown efficacy in alleviating inflammation and neutralizing oxidative stress, the precise mechanisms by which ozonated water attenuates COVID-19 progression are not fully understood. We hypothesized that ozonated water enemas could enrich gut microbiota composition in COVID-19 patients, thereby optimizing the gut environment following faecal transplantation in a murine model.<b>Aim.</b> The overarching aim of this investigation was to ascertain whether ozonated water enemas could exert a salutogenic effect on the gut microbiota in a mouse model, as well as on the holistic gut and systemic health of critically ill COVID-19 patients subsequent to faecal transplantation.<b>Methodology.</b> The entire experiment was conducted over a 14-day period. WT mice were randomly allocated into three groups: Sham, FMT (faecal microbiota transplantation) and FMT+O₃ (FMT with ozonewater enema treatment). Mid-stage faecal specimens were collected from 21 severe COVID-19 patients and randomly divided into seven subgroups (three specimens per subgroup). These specimens were transplanted into the WT mice of the FMT and FMT+O₃ groups via faecal gavage on days 1 through 7. The healthy control group (Sham) received oral administration of ddH₂O instead. Starting on day 8 post-transplantation, the FMT+O₃ group underwent ozone water enema treatment for seven consecutive days. During this treatment period, assessments were performed to evaluate intestinal barrier function, inflammatory changes and alterations in gut microbiota. Additionally, improvements in intestinal, hepatic, pulmonary and systemic lesions were examined.<b>Results.</b> Our findings indicate that ozonated water enemas modulate the SIRT1-Nrf2/HO-1 pathway, significantly enhancing the intestinal environment in mice that received FMT from COVID-19 patients. This intervention increased microbiota populations, strengthened intestinal barrier integrity and reduced intestinal and systemic inflammatory responses.<b>Conclusion.</b> The results highlight the potential of ozonated water enemas as a therapeutic option for COVID-19 patients, particularly in optimizing intestinal microbiota and mitigating inflammatory responses through SIRT1-Nrf2/HO-1 pathway modulation. This approach offers a novel strategy for addressing residual effects of COVID-19.