| Background:Burns are usually an injury to the body caused by heat,chemicals,and electrical currents.In particular,after thermal（e.g.,hot water,hot oil）injury,the protective mucosal barrier of the skin is destroyed,and in severe patients,direct submucosal injury,such as muscle,is also caused.Severe burns can also cause damage to many organs,and the liver is one of the more severely damaged organs.Fatty acid binding protein（FABP）was originally discovered by an American scientist and is found mainly in mammalian tissues such as adipose tissue,heart muscle and liver.One of the most widely studied proteins is fatty acid binding protein 4,which is mainly found in macrophages and adipocytes,and has been previously shown to be associated with many diseases（tumors,obesity,cardiovascular disease,etc.）.Previous studies by our group showed that FABP4 expression levels were increased in the liver of severely scalded rats,and endoplasmic reticulum stress also occurred,but whether liver dysfunction after scalding is related to FABP4 expression levels and through which pathway FABP4 may cause liver injury is unclear and needs to be explored in more depth.Therefore,this experiment aims to investigate the molecular mechanism of liver injury caused by FABP4 after severe burns through in vivo and in vitro experiments.Methods:1.1.Animal experiment: 10 220g-260 g female SD rats were divided into sham injury group and simple scald group according to the random number table method,with 5 rats in each group.The rats were first acclimatized for one week after collection.The rats were anesthetized with 10% chloral hydrate（3 ml/kg）before the start of the experiment,the back hair of the two groups of rats was shaved after the onset of anesthesia,leaving30% of the overall surface area for scalding.The back of the rats in the sham injury group were placed in 37℃ water temperature for 15 seconds to simulate scalding,and the back of the rats in the scalding group were placed in 98℃ water temperature for 15 seconds to cause 30% overall surface area third degree scalding.Immediately after injury,both groups of rats were rehydrated（intraperitoneal injection of sodium lactate Ringer’s solution,45 ml/kg）to prevent shock,and silver sulfadiazine was applied topically to protect the wounds.The rats in both groups were executed 24 h after injury,and the liver tissues were taken under aseptic conditions and blood was obtained from the rats via the abdominal aorta.Hematoxylin-eosin staining（HE）was used to observe liver injury after scalding,and real-time fluorescent quantitative reverse transcription PCR（RT-q PCR）and protein blotting（Western blot）were used to detect the m RNA and protein expression of FABP4 and endoplasmic reticulum stress-related markers in the liver after scalding.2.Cell experiments: This experiment was performed in vitro using Huh7.After plasmid transfection of Huh7,cells were divided into negative control group（NC group）,overexpression FABP4 group（pc DNA3.1-FABP4 group,concentration）and overexpression FABP4+GSK2656157（pc DNA3.1-FABP4+GSK2656157.GSK2656157 concentration was 10 μmol/L）.Changes in the m RNA and protein expression levels of FABP4 as well as endoplasmic reticulum stress-related GRP78 and CHOP in Huh7 were detected by RT-q PCR as well as Western blot techniques,and apoptosis in Huh7 was detected by cell flow techniques.Results:1 The m RNA and protein expression levels of FABP4 in the liver of rats in the scalded group alone were significantly higher than those in the sham-injured group,which indicated that severe scalding could cause high expression of FABP4.2 The protein expression levels of GRP78,CHOP,PERK associated with endoplasmic reticulum stress and caspase-3 associated with apoptosis were significantly higher in the liver of rats in the scalded group alone than in the sham-injured group.3 After Huh7 transfected FABP4 to make it highly expressed,the indicators related to endoplasmic reticulum stress（GRP78,CHOP,PERK）in the cells were significantly higher than those in the NC group,and these indicators were significantly lower than those in the FABP4 overexpression group after the addition of GSK2656157（endoplasmic reticulum stress inhibitor）.4 After transfection of Huh7 with FABP4 to make it highly expressed,the cell viability was significantly lower than that of NC group and the cell flow pattern showed increased apoptosis,and after adding GSK2656157,the cell viability was significantly higher than that of FABP4 overexpression group and the cell flow pattern showed decreased apoptosis.Conclusion:1.Severe burns cause high expression of FABP4 in the liver and the onset of endoplasmic reticulum stress,which in turn can cause liver damage.2.Overexpression of FABP4 can cause the occurrence of endoplasmic reticulum stress in Huh7 cells and cause cell damage,and cell damage is reduced by adding GSK2656157.3.FABP4 may contribute to liver injury by regulating endoplasmic reticulum stress... |
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