| Objective: The mechanism of progressive injury in electrical burns is complex and still unclear.Our previous study found that progressive electrical burns are associated with microvascular injury,microhemodynamics and rheological abnormalities.Burns can make local wounds and microcirculation disorders occur in the distal tissues,causing ischemia and hypoxia in the tissues and organs of the body,leading to cell metabolism disorders.Platelets are an important component of blood,and abnormal rheological behavior not only affects blood flow in the microcirculation,but also affects microvascular structure and function,which release platelet alpha particles,dense particles and lysosomes.PDGF was released from platelet alpha particles in the early stage of injury,and initiated and accelerated tissue wound repair.It is one of the growth factors that appeared early in the wound healing process.Its main role is in promoting wound healing.Among them,the BB type promotes The healing ability is stronger,which helps to strengthen the formation beiof granulation tissue and shorten healing time.PF-5 is also secreted by a particle,which has the effect of enhancing hemostasis.Ulinastatin(UTI)as a broad-spectrum protease inhibitor is clinically used to treat acute pancreatitis mainly,acute and chronic pneumonia,and sepsis,systemic inflammatory response syndrome.Its main role is to eliminate oxygen free radicals,inhibit the release of inflammatory mediators,improve the body's immunity,etc with UIT,and then reduce the cell and tissue amage caused by various inflammatory reasons,improve the state of tissue microcirculation and so on.UTI is non-immunogenic and has little side effects and less side effects on the body being easily used in clinical practice.This experiment aims to analyze the changes of serum PDGF and PF-5 levels in rats at early stage after high-voltage electric burn,and to give UTI intervention to explore the feasibility of UTI treatment of high-voltage electric burns and their complications.Method:1.Experimental animals: Healthy adult SD rats,male,180(weight 220-310 g,certificate number: 1411023;purchased from Experimental Animal Center of Hebei Medical University).2.Grouping and administration: Randomized block design were used.The rats were randomly divided into high voltage electric burn saline group(saline group),high voltage electric burn group(electrical injury group),and UIT treatment after high voltage electric burn(UIT groups)(each=60).60 rats in each group were randomly divided into 15 minutes before high-voltage electric injury,5 minutes after electric injury,1 hour,2 hours,4 hours,and 8 hours,that is total 6 phases groups(each=10).3.High piezoelectric burn rat model was prepared:1)Preparation of experimental drugsUTI solution was prepared at a dose of 20,000 units/kg(calculated as rat body weight)and the injection volume was 2 ml/kg.Chloral hydrate:0.3ml/100g(calculated according to rat body weight)2)Model Preparation(1)Electric shock equipment circuit connection: Correctly connect the electric circuit,check the safety of the experimental circuit and the accuracy of components and circuits.(2)Anesthetized rats: Each group of rats was anesthetized with chloral hydrate solution intraperitoneally,and the depth of anesthesia was noted.(3)Model operation:The rats were fixed and connected to the circuit: After the success of the anesthesia,the rats of the 3 groups were fixed on the circuit insulation board in the supine position,and the left fore limb and the right hind limb were connected to a 1cm×1cm electrode clip.The left forelimb clip connects the fire wire and the right hind limb clip connects the zero line.The left foreleg is the current inlet and the right hind limb is the current outlet.The closed circuit establishes the electric burn model: Make sure that the circuits are all connected correctly,turn on the power,adjust booster output voltage to 2k V,turn on the output to close the circuit.The experimental rat was subjected to contact high-voltage electric shock,and the electric shock time was controlled for 3 seconds;then the electric gate of the booster output was disconnected and the main power was turned off.The control group's circuit operation method was the same as that of the electric injury group and the UIT group,but the power was not turned on and false electricity was given.Administration in each group: Rats of saline group were injected intraperitoneally with saline,and the injection was 2 ml/kg.UIT rats were injected intraperitoneally with the prepared UTI(20,000 units/kg ie 2 ml/kg).Each group of rats recorded the time of shock.4.Specimen collection: Heart blood was collected from each group of corresponding phase groups.Each rat needs to collect about 5-6ml of whole blood and stand for about 30 min,centrifuged at 3000 rpm for 10 min.After centrifugation,the supernatant was taken and stored in a-70°C freezer for use.5.Index detection: The ELISA double antibody sandwich method was used to detect the levels of PF-5 and PDGF in the serum of each phase of each group.In this experiment,the content of each index was measured as OD value,and the standard product was drawn according to the reagent specification.The curve was fitted to calculate the OD value of PF-5 and PDGF in serum.6.Data Analysis: The experimental data are expressed as mean±standard deviation((?) ±s),and SPSS 21.0 statistical software was used for statistical analysis.The analysis of variance of the factorial design data of two factors was performed.Multiple comparisons were performed using the LSD-t test.P<0.05 was considered as a significant difference.Result:1.Changes in rat PDGF contentThe serum level of PDGF was significantly higher in the electric injury group than that in the saline group(F=14.707,P<0.05).There was a statistically significant difference between the rats in the electric injury group and the level of PDGF in the saline group.The serum levels of PDGF in rats with different phases after electrical injury were significantly different(F=14.180,P<0.05),and higher at 2h and 8h.(Fig1,Table 1).The total serum levels of PDGF in the rats of the UIT group after electrical injury were compared with that of the saline group(F=17.407,P<0.05).The difference was statistically significant.The PDGF content in the serum of the UIT group and the saline group rats The levels of PDGF in serum were different.The levels of serum PDGF in rats at different phases had statistically significant differences(F=17.587,P<0.05),and they were higher at 1h and 2h.(Fig1,Table 1).2.Rat PF-5 content changesCompared with the saline group,there was a significant difference in the serum total PF-5 level between the electric injury group and the saline group(F=9.571,P<0.05).The serum PF-5 content in the electric injury group and the saline group rats The content of PF-5 in serum was different.There was a significant difference in serum PF-5 content between different phases after injury(F=9.515,P<0.05),and it was higher at 5 minutes,2 hours,and 8 hours.Compared with the saline group,there was a significant difference in the serum total PF-5 between the ulinage group and the saline group(F=15.170,P<0.05).The PF-5 content in the serum of the UIT group was similar to that of the saline group.The content of PF-5 in serum was different;the difference of PF-5 content in rats at different phases was statistically significant(F=16.381,P<0.05),and it was higher at 1h,2h,and 8h.(Fig2,Table 2).Conclusion:1.High voltage burns can increase the level of PDGF in the blood of rats.The content of PDGF increases gradually with time in 8 hours after injury.2.High-voltage electric burns can increase the content of PF-5 in the blood of rats.The content of PF-5 increases gradually with time in 8 hours after injury.3 Early UTI treatment of high-voltage piezo burns can reduce the content of PDGF and PF-5 in blood of rats after electrical injury,and promote trauma tissue repair after electric injury.However,the extent and specific ways in which UTI reduces the content of PDGFand PF-5 need further exploration. |
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