A Novel Post-thoracoscopic Surgery Pain Mouse Model Reveals Postoperative Behavioral Profiles And Gut Microbiota Signatures

Background Postoperative incision pain in the chest is an important postoperative pain.Clinical studies have found that incision pain after thoracic surgery is severe and has a high incidence,ranking second in postoperative pain in all surgeries,causing huge physical and psychological burdens to patients and their families.The use of thoracoscopy in recent years is expected to reduce trauma and postoperative pain associated with thoracic surgery.However,studies have shown that the application of thoracoscopy does not significantly reduce the incidence of postoperative pain.At the same time,chronic postoperative pain is often secondary to higher brain dysfunction,such as negative anxiety and cognitive impairment.However,postoperative chronic pain lacks effective clinical pain management methods,and drug intervention is often complicated by serious side effects such as opioid addiction.Therefore,we urgently need to elucidate the pathophysiological mechanism of the occurrence and development of postoperative incision pain and find effective drug intervention targets.In order to systematically and deeply study the neural mechanism of incision pain after thoracoscopic surgery,we need an animal model that can simulate postoperative pain after thoracoscopic surgery.However,there is currently a lack of animal models that can directly simulate postoperative pain after thoracoscopic surgery.According to previous studies,the gut microbiota affects the behavioral phenotypes of the nervous system through the gut-brain axis.A variety of gut microbes affect brain function by secreting different metabolites.For example,the metabolism of caffeine in the gut is significantly correlated with chronic pain.At the same time,secondary bile acids,short-chain fatty acids,and bioactive peptides produced by gut hormones produced by the gut microbiota pass through the gut-blood barrier and the blood-brain barrier and affect the higher brain functions of the brain,such as negative anxiety and cognitive function.Moreover,clinical studies have found that surgery can lead to intestinal flora dysfunction.Therefore,research targeting the gut microbiota in chronic postoperative pain has the opportunity to provide us with potential therapeutic targets and early diagnosis of chronic pain and its complications—negative anxiety and cognitive impairment biomarkers Methods1)Animal behavioral test: The anxiety-like behavior of mice was detected by open field test,elevated plus maze test,and marble buried test.Detect cognitive function in mice using novel object recognition experiments.2)Screening of neuronal activity: use immunofluorescence experiments to screen immediate early genes to explore the functional activities of brain regions related to animal behavioral phenotypes.3)Intestinal flora metagenomic detection: The genome of the intestinal flora of mice was comprehensively detected by the shotgun method.4)Detection of intestinal flora metabolome: A comprehensive detection of small-molecule metabolites of mouse intestinal flora is carried out by using non-targeted metabolome.Results1)A new type of non-invasive tracheal intubation method for mice was perfected and improved,and the success rate of non-invasive tracheal intubation in mice was improved.2)The pain behavioral manifestations and related experimental parameters of the pain after thoracoscopic surgery(PTSP)mouse model were explored: compared with the sham surgery(Sham)group,the PTSP group mice were induced by compression of a 2 mm steel column for 1 hour.Significant mechanical hyperalgesia;compared with the Sham group,the PTSP group mice also induced significant mechanical hyperalgesia after 2 hours of compression with a 2 mm steel column;compared with the Sham group,the PTSP group mice 1 mm No significant mechanical hyperalgesia was observed after 1 hour of compression with the steel column.3)Chronic pain after simulated thoracoscopy can lead to obvious anxiety-like behaviors:compared with mice in the Sham group,mice in the PTSP group had decreased activity in the central area of the open field,decreased activity in the open-arm area of the elevated plus maze,and increased the number of buried balls.4)Chronic pain after simulated thoracoscopy can lead to significant cognitive impairment:compared with the Sham group,the PTSP group mice had no significant difference in the recognition of the same block;compared with the Sham group,the PTSP group mice Group mice took significantly less time to recognize novel objects.5)Abnormal activation of multiple brain regions in the central nervous system was observed in a mouse model simulating chronic pain after thoracoscopic surgery: compared with the mice in the Sham group,the anterior cingulate cortex and the ventral hippocampus of the PTSP group mice c-Fos and Arc-positive neurons increased activation.6)Chronic pain after simulated thoracoscopy can lead to intestinal microbiota and functional disorders in mice: Compared with mice in the Sham group,the PTSP group of mice showed significant differences in intestinal microbiota species,genome,genome function,and small molecule metabolism.There are significant differences at multiple levels,such as the function of small molecule metabolites.ConclusionOur study established a reliable preclinical mouse model that can be used to study postoperative pain and related behavioral abnormalities.Furthermore,our findings reveal significant changes in the gut microbiota and provide experimental evidence for the interaction between the gut microbiota and postoperative pain through the gut-brain axis.