| Objective: Previous studies have found that histone deacetylase inhibitors(HDACIs) can reduce the injury of important organ function caused byhemorrhagic shock and ischemia-reperfusion; recent studies have confirmed thatHDACIs can inhibite the expression of hypoxia inducible factor-1（HIF-1）,andreduce the injury of myocardial induced by hemorrhagic shock.Therefore,thisstudy hypothesizes that HDACIs inhibite apoptosis of cardiomyocyte by reducingthe expression of HIF-1and its downstream target genes caused by lethalburn,and protect the function of heart.Purpose of this study:1.To observe theeffect of HDACIs on the function and blood flow of important organs in rats with50%TBSAⅢ°injury, and confirm that HDACIs have the protective effect onmultiple organ dysfunction caused by burns;2.To study the effect of HDACIs onapoptosis rate of myocardial cells,the expression of HIF and its downstreamtarget genes (iNOS, BNIP3) and caspase-3in fatal burn,and investigate themechanism of HDACIs which can inhibite the apoptosis of cardiomyocyte, andprotect the function of heart.Methods:1Groups and treatments:64male SD rats of clean-level, weight250~300g,adaptive feeding one week after purchase,fasting12hours before operation,drinking water freely.They were randomly divided into5groups:①sham controlgroup(Group SC),②scald+normal saline group(Group SN),③scald+VPA group(Group SV),④scald+SAHA group(Group SS).According to different observationtime, each scald group was divided into two subgroups:3hours after scald(S3)and6hours after scald(S6)（n=8）.2The model of50%TBSA III°burns in rats: rats were intraperitoneallyanesthesised with pentobarbital sodium(50mg/kg),cut off the hair on back andabdomen, then placed in a preformed template, exposing the surface of the skin, while protecting the rest of the skin.The rats in scald groups were immersed intoboiling water(100℃, the back for15s,the abdomen for8s) to produce50%TBSAfull-thickness burn.The sham control group were immersed into warmwater(37℃, the back for15s,the abdomen for8s).At3h or6h after burns,openingabdominal cavity,laser Doppler measured the blood flow of liver,kidney andintestinal.At the end of the experiment,abdominal aorta puncture andexsanguination were used to achieve euthanasia,and collected blood samples andcardical tissues.3Measurements and methods:①Myocardium with paraffin section, calculat-ing the rate of myocardial apoptosis in each group with TUNEL method;②Todetect the level of CK-MB,ALT,Cr in central laboratory;③The expression ofHIF-1,iNOS,BNIP3and caspase-3were detected by Western blot assay;④theactivity of caspase-3was measured by detection kits, the level of NSE in plasmaand NO in heart tissue were detected by ELISA method;⑤The blood flow of liver,kidney, intestinal were monitored with laser-Doppler flowmerer.Results:1The apoptosis rate of cardiomyocytes：the apoptosis rate of cardiomyocy-tes in scald and HDACIs treatment groups were significantly higher than thesham control group(all P<0.05) after burns, the scald+HDACIs treatment groupswere significantly lower than the scald+normal saline group (all P<0.05); thecomparison of HDACIs treatment groups,at3h and6h after burns, Group SVwas significantly higher than Group SS (all P<0.05).2The activity and content of caspase-3: the activity and content of caspase-3in scald and HDACIs treatment groups were significantly higher than the shamcontrol group(all P<0.05)after burns, the scald+HDACIs treatment groups weresignificantly lower than scald+normal saline group(all P <0.05);the comparisonof HDACIs treatment groups,at3h after burns,there was no significantlydifference between Group SV and SS;at6h after burns,Group SS wassignificantly lower than GroupSV (P<0.05).3The content of NO: the content of NO in scald and HDACIs treatmentgroups were significantly higher than sham control group(all P<0.05) after burns, the scald+HDACIs treatment groups were significantly lower than thescald+normal saline group(all P<0.05);the comparison of HDACIs treatmentgroups, at3h and6h after burn, Group SS was significantly lower than Group SV(all P<0.05).4Western blot:the expression of HIF-1and its downstream target genes iNOS、BNIP3in scald and HDACIs treatment groups were significantly higherthan the sham control group (all P<0.05)after burn, the scald+HDACIs treatmentgroups were significantly lower than the scald+normal saline group(allP<0.05);the comparison of HDACIs treatment groups,at3h and6h after burns,the expression of HIF-1、iNOS、BNIP3in Group SV was significantly higer thanGroup SS(all P<0.05).5The content of CK-MB:the content of CK-MB in scald and HDACIstreatment groups were significantly higher than the sham control group(allP<0.05) after burns,the scald+HDACIs treatment groups were significantly lowerthan the scald+normal saline group at6h after burns(all P<0.05);the comparisonof HDACIs treatment groups, at3h after burns,there was no significantlydifference between HDACIs treatment groups;at6h after burns,Group SV wassignificantly higer than Group SS (P<0.05).6The content of ALT: the content of ALT in scald and HDACIs treatmentgroups were significantly higher than the sham control group(all P<0.05) afterburns,the scald+HDACIs treatment groups(Group SV)were significantly lowerthan the scald+normal saline group(all P<0.05), there was no significantlydifference between Group SS and the scald+normal saline group; the comparisonof HDACIs treatment groups,at3h and6h after burns,Group SS was significantlyhiger than Group SV (all P<0.05).7The content of CR:the content of CR in scald and HDACIs treatmentgroups were significantly higher than the sham control group(all P<0.05) afterburns,the scald+HDACIs treatment groups(Group SV) were significantly lowerthan the scald+normal saline group(all P<0.05), Group SS was significantly lowerthan scald+normal saline group(P<0.05)at3h after burns;the comparison ofHDACIs treatment groups,at3h after burns,there was no significantly difference between the HDACIs treatment groups;at6h after injury,Group SS wassignificantly higer than Group SV(P<0.05).8The content of NSE:the content of NSE in scald and HDACIs treatmentgroups were significantly higher than the sham control group(all P<0.05) afterburns,the scald+HDACIs treatment groups were significantly lower than thescald+normal saline group(all P<0.05);the comparison of HDACIs treatmentgroups,at3h and6h after burns, there was no significantly difference betweenHDACIs treatment groups.9The blood flow of liver, kidney, intestinal:the blood flow of liver, kidney,intestinal in scald and HDACIs treatment groups were significantly lower thanthe sham control group(all P<0.05)after burn;in liver,at3h after burns, Group SSwas significantly higer than Group SN（P<0.05）,there was no significantlydifference between Group SV and Group SN, at6h after burns, Group SV wassignificantly higer than Group SN（P<0.05）,there was no significantly differencebetween Group SS and Group SN;in kidney, at3h after burns, Group SS wassignificantly higer than Group SN（P<0.05）, Group SV was significantly lowerthan Group SN（P<0.05）, at6h after burns, there was no significantly differencebetween Group SN, Group SV and Group SS; in intestinal, at3h and6h afterburns, Group SV and SS was significantly higher than Group SN（Pall<0.05）,Group SS was significantly higer than Group SV（Pall<0.05）Conclusion:1HDACIs（VPA、SAHA）all can improve the function of liver, kidney,intestine, brain, and the blood flow of liver, kidney and intestinal after fatalburns,and protect the function of important organs.2HDACIs（VPA、SAHA）all can reduce the expression of HIF-1and itsdownstream target gene iNOS、BNIP3in myocardial cell caused by fatal burns,reduce the activity and content of caspase-3,and decrease apoptosis of myocardialcell, and protect the function of heart.3In the aspect of improving organ function,in heart,SAHA was strongerthan VPA,in liver and kidney,VPA was stronger than SAHA,in brain,the twodrugs had no difference;in the aspect of inhibiting apoptosis of myocardial cell and improving the blood flow of liver,kidney,intestinal,SAHA was stronger thanVPA. |
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