Exploring The Relationship Between Tryptophan/kynurenine Metabolic Pathway And The Time Of Head Injury Based On Metabonomics Technology

Background and purposeTraumatic brain injury(TBI)is a brain injury caused by direct or indirect external forces caused by falls,motor vehicle collisions,sports-related injuries,abuse/attack or explosions.It is recognized as one of the main causes of disability and death worldwide due to its high mortality and high disability rate.The most common type of mechanical injury in forensic pathology and clinical appraisal is traumatic brain injury.It mainly identifies the degree of injury and the time of injury.The current identification of the time and extent of brain injury is mainly based on the pathological examination of brain tissue.But pathomorphological changes cannot be used to infer early injury time and lack clear accuracy.Therefore,it is of great significance to seek new methods for inferring the degree and time of brain injury from the perspective of systems biology.Metabolomics is a new type of systems biology technology tool developed in recent years with its characteristics of high efficiency,rapidity,and direct reflection of the physiological and pathological conditions of the body,and has been widely used in the medical field.It is unparalleled in the research of biomarkers.And in previous experiments,we found that the tryptophan/kynurenine pathway changed after traumatic brain injury,and related compounds might become biomarkers for identifying the time of traumatic brain injury.Based on this,this experiment established a rat brain injury model and used high performance liquid chromatography-mass spectrometry technology to examine the trend of changes in related compounds in the tryptophan/kynurenine metabolic pathway after different injury time.It was proposed to provide a basic theoretical basis for the time judgment of forensic brain injury.Meoth1.70 SPF male SD rats were randomly divided into 7 groups: control group,3h group,6 h group,12 h group,24 h group,3 d group,7 d group.(n=10)A rat TBI model was prepared using a simulated TBI striking device adapted to this experiment based on an animal model of Feeney rat brain injury.After the injury,the rats were put to death at the corresponding time nodes.The serum samples of the rats were collected after death and stored in the-80℃ refrigerator for later use.2.Used UPLC-MS/MS to detect the non-targeted metabolomics of injured rat serum and analyze the change trend of related small molecule compounds.3.High performance liquid chromatography tandem mass spectrometry detection was established for tryptophan,kynurenine,kynurenic acid and quinolinic acid,and the detection line,precision,accuracy,recovery rate,etc.of the detection method Indicators were investigated.4.Used the method established in this project to determine the related compounds in the serum samples of rats after brain injury and get the results.Results1.In this experiment,through the detection of non-targeted metabolome,it was found that the endogenous compounds kynurenine and quinolinic acid in the tryptophan/kynurenine metabolic pathway change regularly over time,which could be a biomarker for diagnosing the time of brain injury.And the changes found in small molecule compounds could provide some insights into the pathophysiology after brain injury2.In this experiment,a detection method for compounds related to the tryptophan/kynurenine metabolic pathway was established.The detection limit of each compound was between 2-20 ng/m L,and the precision and accuracy of the method were 0%-15%.The recovery rate was between 80% and 106%,which conformed to the relevant standards of methodology.It can be written to meet the needs of measurement3.The determination of related compounds in the serum of rats with traumatic brain injury showed that the content of each compound in the serum of rats after the brain injury changed as follows: the content of tryptophan did not change significantly within 7 days;The content of kynurenine began to rise within 1 hour after injury,reached a peak within 3 days after injury,and then began to decrease;the content of kynurenic acid increased at various time points after injury,but there was no obvious pattern;Quinolinic acid after injury reached the highest peak after 12 h and then began to decrease.The ratio of tryptophan to kynurenine content gradually decreased and reached the lowest point within 3 days.Conclusion1.This experiment successfully established a targeted metabolomics method for the tryptophan/kynurenine metabolic pathway,and realized the analysis of related compounds at the animal level.2.The change of tryptophan/kynuric acid metabolic pathway can be used as a basis for judging the time of brain injury.