| Inhalation anesthetics have been proven to be safe and effective for induction and maintenance of anesthesia.Isoflurane is one of the most widely used inhalation anesthetics in clinic.Isoflurane anesthesia can inhibit cardiopulmonary function,leading to carbon dioxide accumulation and hypoxemia.Metabonomics,as a new discipline,is widely used in many fields of biology.Many changes that cannot be detected through genomics,transcriptome,and proteomics,can be found by metabonomics technology.GC-MS technology is widely used in metabonomics research.The purpose of this study was to compare the changes of physiological parameters in dogs after prolonged anesthesia with different concentrations of isoflurane,including body temperature,circulatory system and respiratory system,and to explore the rational dosage of isoflurane in order to provide reference for the clinical application of isoflurane in veterinary medicine.The changes of plasma metabolites in dogs after prolonged anesthesia with 2%isoflurane were analyzed by GC-MS technology to reveal the effect of isoflurane on metabolic regulation mechanisms in vivo.1 Effect of isoflurane anesthesia on physiological parameters in dogsFifteen dogs were divided into three groups randomly with 5 dogs in each group.These dogs were anesthetized with 2%,3%and 4%isoflurane for three hours.The body temperature,respiratory and circulatory system were monitored during anesthesia and the data were analyzed.The results showed that 2%,3%and 4%isoflurane maintenance anesthesia had dose-dependent inhibitions on circulatory system and respiratory system in dogs.The higher the concentration of isoflurane was,the more significant the inhibition was.Cardiac rhythm and electrocardiographic waves of these three groups were basically normal,and Q-T intervals of three groups prolonged,and S-T segments of three groups all moved downward.There were no significant changes in myocardial enzymes of the three groups.There were no significant changes in arterial blood gas indexes in dogs which were anesthetized with 2%and 3%isoflurane and the pH values of dogs which were anesthetized with 4%isoflurane declined significantly.The results showed that isoflurane has a dose-dependent inhibition on cardiopulmonary function and it was safer to maintain anesthesia with 2%or lower concentration of isoflurane.2 Plasma metabolomics profile of isoflurane anesthetized dogs based on GC-MS technologyBlood samples of 5 Schnauzer dogs were collected 30 minutes before anaesthesia(Class 1),isoflurane maintenance for 6 hours(Class 2)and 24 hours after anesthesia(Class 3)for metabolomics analysis.Endogenous metabolites in plasma were identified by GC-MS technology and NIST mass spectrometry database.Differential metabolites were screened out via multivariate statistical analysis and t-test.In the final step,KEGG was used for enrichment analysis of metabolic pathways to identify the significantly different metabolic pathways.The results showed that there was significant difference in metabolites between Class 1 and Class 2,but there was no significant difference between Class 1 and Class 3.Compared with Class 1,67 differential metabolites were filtered in Class 2,of which 37 metabolites could be named accurately.Fourteen metabolites which could be related to isoflurane were screened out by enrichment analysis of KEGG metabolic pathway.Leucine,valine,maleic acid,isoleucine,creatine,oxyproline,lysine and trehalose increased after anaesthesia for 6 hours,while succinic acid,uracil,lactic acid,citric acid,alpha ketoglutarate and alpha-D-glucose 1-phosphate decreased after anesthesia for 6 hours.These metabolites were mainly participated in carbohydrate,amino acid and nucleotide metabolism.The results indicated that carbohydrate,amino acid and nucleotide metabolism in dogs were disordered after anesthesia for 6 hours,while the effect of isoflurane anesthesia on metabolism in dogs returned to the normal after 24 hours. |
