OBJECTIVETo observe the changes in surface microcirculation of pancreas after high-voltage electric burn (HEB).

METHODSThirty rabbits were divided into electrical injury (E) group and control (C) group in a simple random method, with 15 rabbits in each group. Rabbit model of HEB was reproduced from E group with TC-30-20KVA type voltage regulator and YDJ-10KVA type experimental transformer. Rabbits in C group were shamly burned with the same equipment as in E group but not electrified. Intravenous blood of rabbits in both groups was drawn 15 mins before HEB and 0, 1, 2, 4, 8 h after to determine the levels of serum amylase and blood glucose. The morphology of the pancreas microvessels and its surrounding tissues, and the dynamic changes in microvascular blood flow were observed with WX-9 microscope and its image analytical system.

RESULTSThe level of serum amylase of rabbits in E group increased gradually and peaked (849 +/- 39) U/L at 8 post HEB h (PHH), which decreased gradually reaching the nadir (153 +/- 21) U/L at 8 PHH in C group (P < 0.05). The blood glucose levels of rabbits in E group and C group increased gradually, with the former level obviously higher than the latter (P < 0.05). Arteriole, venule and capillary network on the surface of pancreatic lobules of rabbits in both groups were clearly seen and well-distributed in the natural way before HEB. In E group, arterioles of rabbits contracted at 0 PHH, and increased gradually in caliber size at 1 PHH; venules of rabbits were unevenly thickened at 2 PHH, and dilated at 8 PHH; the capillaries were contracted or with interrupted flow or completely obstructed at 0 PHH, and their thickness were uneven at 2 PHH, showing exudation at 8 PHH. There was no obvious change of microvessels in rabbits in C group at each time point. There was no exudation and bleeding around the microvessels on the pancreas surface of rabbits in both groups before HEB. In E group exudation was observed around microvessels at 1 PHH, bleeding was observed at 2 PHH and became obvious at 4 PHH; exudation and diffuse bleeding from capillaries were observed at 8 PHH. There was no exudation and bleeding in rabbits in C group as observed at each time point. Before HEB, blood flow speed in microvessels of rabbits in 2 groups was similar to each other (P > 0.05), and no erythrocyte aggregation or microthrombus was found in both groups. In E group, blood flow speed slowed down at 0 PHH as compared with that before HEB, it accelerated at 1 h and slowed down later; erythrocyte aggregation in venules and capillaries was found at 0 PHH, and it aggregated gradually. No above-mentioned change was found in C group.

CONCLUSIONSHEB produces microcirculation disturbance and functional disturbance of pancreas.

Animals ; Burns, Electric ; blood ; pathology ; Female ; Male ; Microcirculation ; Pancreas ; blood supply ; pathology ; Rabbits

OBJECTIVETo study the changes in bulbar conjunctiva microcirculation (BCM) and the therapeutic effect of Pentoxifylline on BCM disturbance after high-voltage electrical burn (HEB) in rabbits.

METHODSForty-five rabbits were divided into control group (C), electrical burn group (EB), and Pentoxifylline treatment group (PT) according to random number table, with 15 rabbits in each group. Model of HEB was reproduced in rabbits from EB and PT groups with voltage regulator and experimental transformer. Rabbits in C group were sham injured with the same devices without electrification. Changes in BCM were observed with microcirculation microscope at 15 minutes before HEB and 5 minutes, 1, 2, 4, 8 hour(s) post HEB (PHM or PHH), including: (1) morphology of microvessels, such as the discernible, diameters of arterioles, venules, and capillaries, the unevenness in caliber, and ischemic area; (2) dynamic changes in microvascular blood flow, such as blood flow speed in arterioles, venules, and capillaries, erythrocyte aggregation, and microthrombi formation; (3) condition of tissues surrounding microvessel, such as bleeding and exudation. Measurement data were processed with t test; enumeration data were processed with Fisher's exact test.

RESULTS(1) Morphology of microvessel: discernible of microvessels in EB and PT groups was decreased, but that of PT group was better than that of EB group. At PHM 5, diameter of arterioles, venules and capillaries was respectively (7.3+/-2.5), (12.3+/-2.4), (3.5+/-0.7) microm in EB group, all narrower than those of the control group [(14.6+/-3.1), (27.2+/-3.5), (9.0+/-1.4) microm, with t value respectively 5.23, 13.66, 14.04, P values all below 0.05]. Diameters of the microvessels in PT group [(10.2+/-3.8), (21.5+/-3.1), (7.1+/-1.2) microm] were larger than those in EB group (with t value respectively 2.21, 8.99, 10.18, P values all below 0.05). Diameters of arterioles, venules and capillaries in EB and PT groups recovered to the before HEB size at PHH 1. From PHH 2 to 8, arterioles and capillaries decreased gradually in caliber, venules dilated gradually in EB and PT groups, but the changes in PT group were not obvious. Thickness of microvessel was observed uneven in EB group at PHM 5, which lasted until PHH 8. Ischemia of the tissue was observed in EB group at PHM 5, which improved at PHH 2. Situation in PT group was better. (2) Dynamic changes in microvascular blood flow: at PHM 5, blood flow speed in arterioles, venules and capillaries was respectively (202+/-53), (198+/-44), (46+/-12) microm/s in EB group, all slower than those of the control group [(544+/-37), (359+/-32), (220+/-19) microm/s, with t value respectively 20.47, 11.51, 30.02, P values all below 0.05], and those of PT group [(335+/-42), (260+/-35), (119+/-23) microm/s] were faster than those of EB group (with t value respectively 7.55, 4.26, 14.85, P values all below 0.05). Blood flow speed in EB and PT groups recovered to the before HEB level at PHH 1. From PHH 2 to 8, blood flow speed decreased gradually in EB and PT groups, but that of PT group was faster than that of EB group. Erythrocyte aggregation in venules and capillaries was observed in EB group at PHM 5, which eased up at PHH 1, but aggregated at PHH 2, lasting until PHH 8. Obvious microthrombi were observed in EB group at PHH 2, which increased gradually. These changes were less obvious in PT group. (3) Condition of surrounding tissues of microvessel: in EB group, exudation was observed around microvessels at PHH 1, bleeding at PHH 2, with a worsening tendency. Changes in those in PT group were less obvious.

CONCLUSIONSHEB causes disturbance in BCM, but it can be ameliorated by Pentoxifylline.

Animals ; Burns, Electric ; drug therapy ; pathology ; Conjunctiva ; blood supply ; Microcirculation ; Microvessels ; pathology ; Pentoxifylline ; therapeutic use ; Rabbits

OBJECTIVETo investigate the effect of stimulation of toss simulated at sea on shock in severe burn rabbits.

METHODSOne hundred and thirty-two rabbits were randomly divided into normal control group (NC group, n = 6), toss group (T group, with treatment of continuous toss, n = 42), burn group (B group, with treatment of burn, n = 42), burn and toss (BT group, with treatment of continuous toss after burn, n = 42). The level of Cr, BUN, HCT and LA from blood samples in T, BT, B groups were observed at 2, 6, 8, 12, 24, 36, 48 post treatment hour (PTH). The changes in urinary volume was measured during 48 PTH. The histopathologic changes in kidney were observed at above-mentioned time points. The above indices in NC group were also observed.

RESULTSThe mean urinary volume in B group during the first and second 24 PTH was (2.59 +/- 0.23) and (2.86 +/- 0.29) mL/h, while that in BT group was (1.61 +/- 0.13) and (1.66 +/- 0.16) mL/h respectively, which were all lower than those in NC group (6.06 +/- 0.18 mL/h, P < 0.01). The levels of HCT and LA in BT group were obviously higher than those in B group at each time point. The levels of Cr and BUN in BT group at 24, 36, 48 PTH were significantly higher than those in B group. The histopathological observation showed the capillary vessels and mesenchymal cells of kidney glomerulus were congestive, epithelial cells in kidney tubules were swollen. The infiltration degree of inflammatory cells in kidney tubule, and the pathological changes of erythrocyte cast in BT group were more serious than those in B group.

CONCLUSIONThe toss simulated at sea can significantly aggravate shock and the renal damages in severe burn rabbits.

Animals ; Burns ; complications ; Creatinine ; blood ; Erythrocyte Volume ; Kidney ; pathology ; Male ; Motion ; Physical Stimulation ; Rabbits ; Random Allocation ; Shock ; etiology ; pathology

OBJECTIVETo investigate the preventive and therapeutic effects of enalapril maleate (Enalaprilat) (E) on myocardial damage in early stage after burns.

METHODSA total of 60 SD rats were subjected to 30% TBSA III degree scald injury, and randomly divided into scald group (with conventional fluid transfusion after scald) and ENA group (with intraperitoneal injection of 1 mg/kg Enalaprilat after scald). Normal control consisted of 6 rats. Plasma levels of cTnI and CK-MB were determined in all the groups at 1, 3, 6, 12, 24 post-scald hours (PSH) by enzyme linked immunosorbent assay. The pathological changes in myocardium were observed at the same time-points.

RESULTS(1) The serum level of cTnI and CK-MB in scald group were significantly higher than that of normal controls at each time-point (P < 0.01). The serum level of cTnI and CK-MB in ENA group were (1.32 +/- 0.12 microg/L to 2.47 +/- 0.22 microg/L) and (438 +/- 68 U/L to 5569 +/- 322 U/L), respectively, which were obviously lower than those in B group (6.42 +/- 0.96 microg/L to 15.10 +/- 3.69 microg/L) and (2556 +/- 74 U/L to 8047 +/- 574 U/L, P < 0.05 or P < 0.01) at different time-points. (2) Compared with normal controls, cloudy swelling, stromal blood vessel dilatation and congestion inflammatory cell infiltration were observed in scald group, but these pathological changes were less marked in ENA group.

CONCLUSIONSevere myocardial damage in rat occurred early after burns. Enalaprilat injection can markedly alleviate myocardial damage.

Animals ; Burns ; blood ; drug therapy ; pathology ; Creatine Kinase, MB Form ; blood ; Enalapril ; therapeutic use ; Myocytes, Cardiac ; metabolism ; pathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Troponin I ; blood

OBJECTIVETo observe the immunological function changes in T lymphocyte in severe burn patients with sepsis, and to explore its relationship with sepsis.

METHODSFifty-nine burn patients with burn surface exceeding 30% TBSA were enrolled in the study, and they were divided into sepsis group (S, n =43) and non-sepsis group (NS, n = 16). The peripheral venous blood samples of the patients in both groups were collected on 1, 3, 5, 7, 14, 21 and 28 post-burn days (PBD). The T lymphocyte proliferation ability and the interleukin-2 (IL-2) level in both groups were observed and the correlation between them were analyzed. The percentage of CD3+/CD4+ T lymphocytes and its apoptosis rate were determined by flow cytometry and the correlation between them was analyzed.

RESULTSCompared with that in NS group, the proliferation ability of T lymphocyte and the level of IL-2 were significantly decreased in patients in S group on 1, 14, 21, and 28 PBD (P < 0.05 or P < 0.01). The inhibition of T lymphocyte proliferation was positively correlated to the low level of IL-2 production in burn patients (r = 0.82, P < 0.01). The percentage of CD3+/CD4+ T lymphocytes in S group were obviously lower than that in NS group on 1, 5, 14, 21, 28 PBD, whereas on opposite tendency in the apoptosis rate of CD3+ CD4+ T lymphocytes were found at the same time (P < 0.05 or P < 0.01). The percentage of CD3+/CD4+ T lymphocytes was negatively correlated to apoptosis rate of T lymphocytes (r = -0.66, P < 0.05).

CONCLUSIONThe immunological function of T lymphocyte in severely burn patients with sepsis is depressed persistently. Apoptosis of T lymphocyte may participate in the pathological process of cell immunological disorder induced by sepsis.

Adolescent ; Adult ; Burns ; blood ; immunology ; pathology ; Cell Proliferation ; Female ; Humans ; Interleukin-2 ; blood ; Lymphocyte Count ; Male ; Middle Aged ; Sepsis ; blood ; immunology ; T-Lymphocytes ; cytology ; immunology ; Young Adult

OBJECTIVETo observe the level of intracellular reactive oxygen species (ROS) in rats with severe burn and pulmonary microvascular endothelial cells (PMVECs) treated with serum of rat with burn injury, and to investigate the relationship between ROS and apoptosis of PMVECs.

METHODS(1) Twenty-four SD rats were divided into sham injury group ( n = 3) and burn group (n = 21) according to the random number table (the same grouping method below). Rats in burn group were inflicted with 30% TBSA full-thickness scald on the back, and rats in sham injury group were sham injured. Blood samples were collected from abdominal aorta at post injury hour 6, 12, 24, 36, 48, 60, 72 respectively from 3 rats of burn group. The serum content of ROS was assayed by ELISA. The same determination was performed in rats of sham injury group. (2) Five rats were subjected to scald injury as above, and burn serum was prepared 24 hours after injury. Another 5 rats without receiving any treatment were used to prepare normal serum. (3) Marginal pulmonary tissue was harvested from 20 SD young rats. Cells were cultured with tissue block method and indentified with immunohistochemical staining. The third passage of PMVECs in logarithmic phase were inoculated in 6-well plates and 12-well plates. PMVECs in both plates were divided into 4 groups: normal serum group, burn serum group, normal serum + MnTBAP group, and burn serum + MnTBAP group, with 3 wells in each group. Cells in the former 2 groups were respectively cultured with special nutrient solution of endothelial cells without serum added with 15% healthy rat serum or 15% burn rat serum. Cells in the latter 2 groups were cultured with the same culture conditions as in the former two groups correspondingly with addition of 100 µmol/L MnTBAP in the nutrient solution. After being cultured for 24 h, the content of ROS in PMVECs in 6-well plates was detected with flow cytometry. The apoptosis of PMVECs in 12-well plates was observed with acridine orange-ethidium bromide staining, and the apoptosis rate was calculated. Data were processed with one-way analysis of variance and LSD-t test.

RESULTS(1) The serum contents of ROS in rats of burn group were respectively (187 ± 21), (235 ± 22), (231 ± 25), (291 ± 20), (315 ±23) nmol/mL at post injury hour 24, 36, 48, 60, 72, which were significantly higher than that in sham injury group [(141 ± 19) nmol/mL, with t values respectively 7. 86, 9. 57, 13. 87, 14.98, 18.40, P values below 0.01]. (2) Primary cells grew slowly and showed a cobblestone appearance. After passages, cells grew with orderly distribution. The positive rate of coagulation factor VIII of cells was (96 ± 5)% , and thus they were identified as PMVECs. (3) In normal serum group, burn serum group, normal serum + MnTBAP group, and burn serum + MnTBAP group, the contents of ROS in PMVECs were respectively 798 ± 40, 1 294 ± 84, 763 ± 59, 926 ± 42 ( F =93.01, P <0.01), and the apoptosis rates of PMVECs were respectively (6.2 ± 1.3)%, (57.3 ± 6. 7)%, (3.7 ± 0. 8)%, (28.7 ± 5. 7)% (F = 224.50, P <0.01) after being cultured for 24 h. Compared with those of normal serum group, the content of ROS and apoptosis rate of PMVECs in burn serum group increased significantly (with t values respectively 10.40 and 49.06, P values below 0.01). The content of ROS and apoptosis rate of PMVECs in burn serum + MnTBAP group were significantly lower than those in burn serum group (with t values respectively 7.48 and 23.94, P values below 0.01).

CONCLUSIONSSerum content of ROS was increased in severely burned rats. Burn rat serum stimulation on PMVECs can lead to the increase of the intracellular ROS and induce apoptosis. However application of MnTBAP can scavenge ROS and reduce the apoptosis induced by burn rat serum.

Animals ; Apoptosis ; Burns ; blood ; therapy ; Endothelial Cells ; pathology ; Enzyme-Linked Immunosorbent Assay ; Lung ; blood supply ; Oxygen ; Rats ; Reactive Oxygen Species ; blood ; Serum ; metabolism

BACKGROUND: Major burn injury induces an inflammatory response that is accompanied by the release of various cytokines. We investigated the gradual changes in the levels of pro-inflammatory and anti-inflammatory cytokines following burn injury and determined the relationship between these levels and burn size in adult Korean patients with burn injury. METHODS: Blood samples from 9 healthy controls and 60 Korean burn patients were collected on days 1, 3, 7, 14, and 21 after burn injury, and concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and granulocyte-colony stimulating factor (G-CSF) were measured. Burn patients were divided into 3 groups according to burn size (15-30%, 31-50%, >50% total body surface area), and the concentrations of the cytokines were compared between these groups and the control group over 3 weeks. RESULTS: Compared to their levels in controls, IL-6, IL-8, IL-10, TNF-alpha, and G-CSF levels in burn patients were significantly higher during the observation period. Median concentrations of IL-8, IL-10, and G-CSF at each time point increased with burn size, although peak levels and time to peak levels of these cytokines differed from patient to patient. CONCLUSIONS: These findings indicate that IL-6, IL-8, IL-10, TNF-alpha, and G-CSF are important mediators in inflammatory changes after burn injury; however, various factors, including burn size, may influence the concentrations of these cytokines.
Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group ; Burns/blood/*pathology ; Granulocyte Colony-Stimulating Factor/*blood ; Humans ; Interleukin-10/*blood ; Interleukin-6/*blood ; Interleukin-8/*blood ; Male ; Middle Aged ; Republic of Korea ; Time Factors ; Tumor Necrosis Factor-alpha/*blood ; Young Adult

BACKGROUND: Major burn injury induces an inflammatory response that is accompanied by the release of various cytokines. We investigated the gradual changes in the levels of pro-inflammatory and anti-inflammatory cytokines following burn injury and determined the relationship between these levels and burn size in adult Korean patients with burn injury. METHODS: Blood samples from 9 healthy controls and 60 Korean burn patients were collected on days 1, 3, 7, 14, and 21 after burn injury, and concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and granulocyte-colony stimulating factor (G-CSF) were measured. Burn patients were divided into 3 groups according to burn size (15-30%, 31-50%, >50% total body surface area), and the concentrations of the cytokines were compared between these groups and the control group over 3 weeks. RESULTS: Compared to their levels in controls, IL-6, IL-8, IL-10, TNF-alpha, and G-CSF levels in burn patients were significantly higher during the observation period. Median concentrations of IL-8, IL-10, and G-CSF at each time point increased with burn size, although peak levels and time to peak levels of these cytokines differed from patient to patient. CONCLUSIONS: These findings indicate that IL-6, IL-8, IL-10, TNF-alpha, and G-CSF are important mediators in inflammatory changes after burn injury; however, various factors, including burn size, may influence the concentrations of these cytokines.
Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group ; Burns/blood/*pathology ; Granulocyte Colony-Stimulating Factor/*blood ; Humans ; Interleukin-10/*blood ; Interleukin-6/*blood ; Interleukin-8/*blood ; Male ; Middle Aged ; Republic of Korea ; Time Factors ; Tumor Necrosis Factor-alpha/*blood ; Young Adult

OBJECTIVETo observe the efficacy of fenofibrate for hepatic steatosis in rats after severe burn.

METHODSTwenty-seven male SD rats were divided into sham injury group, burn group, and burn+ fenofibrate group according to the random number table, with 9 rats in each group. Rats in sham injury group were sham injured on the back by immersing in 37 ℃ warm water for 15 s and then remained without other treatment. Rats in burn group and burn+ fenofibrate group were inflicted with 30% total body surface area full-thickness scald (hereinafter referred to as burn) on the back by immersing in 98 ℃ hot water for 15 s, and then they were intraperitoneally injected with lactated Ringer's solution at post injury hour (PIH) 1. From PIH 24 to post injury day (PID) 8, rats in burn+ fenofibrate group were treated with fenofibrate in the dose of 80 mg·kg(-1)·d(-1), while those in burn group were treated with equivalent volume of saline. (1) Three rats of each group were respectively selected on PID 4, 6, and 8 for the collection of inferior vena caval blood samples. Serum content of total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), high density lipoprotein (HDL), and low density lipoprotein (LDL) was determined with fully automatic biochemical analyzer. Body mass of each rat was measured immediately after blood sampling, and then rats were sacrificed to collect liver tissue for weighing wet mass. The ratio of wet mass of liver tissue to body mass (liver index) was calculated. Meanwhile, gross observation of liver was performed. (2) One liver tissue sample was harvested from each rat at each time point to observe histopathologic changes with HE staining. One liver tissue slice of each rat at each time point was collected to evaluate degree of hepatic steatosis, and the number of rats in each group in each grade of hepatic steatosis was recorded. Measurement data were processed with analysis of variance of factorial design and SNK test, and enumeration data were processed with Kruskal-Wallis test and Nemenyi test.

RESULTS(1) The content of TC, TG, FFA, and HDL of rats in burn group on PID 4 was obviously different from that in sham injury group (with P values below 0.05). Compared with that in burn group, the content of TC, TG, and FFA of rats was significantly decreased (with P values below 0.05), while the content of HDL of rats was not obviously changed in burn+ fenofibrate group on PID 4 (P>0.05). There were no obvious differences in the content of LDL of rats among 3 groups on PID 4 (with P values above 0.05). The content of TC, TG, and HDL of rats in burn group on PID 6 was obviously different from that in sham injury group (with P values below 0.05). Compared with that in burn group, the content of TC and TG of rats was significantly decreased (with P values below 0.05), while the content of HDL of rats was significantly increased in burn+ fenofibrate group on PID 6 (P<0.05). There were no obvious differences in the content of FFA and LDL of rats among 3 groups on PID 6 (with P values above 0.05). The content of TC and HDL of rats in burn group on PID 8 was obviously different from that in sham injury group (with P values below 0.05). Compared with that in burn group, the content of TC of rats was significantly decreased (P<0.05), while the content of HDL of rats was not obviously changed in burn+ fenofibrate group on PID 8 (P>0.05). There were no obvious differences in content of TG, FFA, and LDL of rats among 3 groups on PID 8 (with P values above 0.05). (2) The texture of liver tissue of rats in burn+ fenofibrate group at each time point was tender and soft, without oil or fat on the section, which was close to the gross condition of liver of rats in sham injury group. Dark yellow plaque scattered on the surface of liver tissue of rats in burn group at each time point with oil and fat on the section, which was especially obvious on PID 6. There was no obvious difference in liver index of rats among 3 groups on PID 4 (F=1.63, P>0.05). On PID 6 and 8, the liver indexes of rats in sham injury group, burn group, and burn+ fenofibrate group were 0.0416±0.0016, 0.0533±0.0054, and 0.0370±0.0069; 0.0423±0.0034, 0.0624±0.0005, and 0.0444±0.0042 respectively. The liver indexes of rats in burn group on PID 6 and 8 were significantly higher than those in the other two groups (with P values below 0.05). There were no obvious differences in the liver indexes of rats between burn+ fenofibrate group and sham injury group on PID 6 and 8 (with P values above 0.05). (3) The liver tissue structure of rats in sham injury group was normal at each time point. Hepatic steatosis of rats in burn group at each time point appeared microvesicular and disperse, which was especially obvious on PID 6. Mild hepatic steatosis was observed in rats of burn+ fenofibrate group on PID 4, and then the structure of liver tissue gradually recovered to normal level from PID 6 on. The degree of hepatic steatosis of rats in sham injury group was 0 grade. One rat in I grade, 1 rat in II grade, and 7 rats in III grade were observed in hepatic steatosis of rats in burn group. Three rats in 0 grade, 4 rats in I grade, and 2 rats in II grade were observed in hepatic steatosis of rats in burn+ fenofibrate group. The degree of hepatic steatosis of rats in burn group was more severe than that in the other two groups (with χ(2) values respectively 56.25 and 162.44, P values below 0.05). The degree of hepatic steatosis of rats in burn+ fenofibrate group was more severe than that in sham injury group (χ(2)=27.51, P<0.05).

CONCLUSIONSFenofibrate can ameliorate the dyslipidemia of severely burned rat, and it can alleviate the degree of hepatic steatosis in certain degree.

Animals ; Burns ; pathology ; Cholesterol, HDL ; blood ; Cholesterol, LDL ; blood ; Dyslipidemias ; drug therapy ; Fatty Acids ; blood ; Fenofibrate ; pharmacology ; Liver ; pathology ; Liver Cirrhosis ; drug therapy ; Male ; Rats ; Rats, Sprague-Dawley ; Triglycerides ; blood

OBJECTIVETo investigate the protective effect of insulin on vascular endothelial cells of rats at early post-burn stage,and its mechanism.

METHODSAdult male Sprague-Dawley rats were randomly divided into 3 groups: i. e, sham scald group (n = 7), scald group (n = 7) and treatment group (n = 7). The rats in the latter 2 groups were subjected to 30% TBSA full-thickness burns with 94 degrees C water, and the sham scald rats were treated with 37 degrees C water. Intra-peritoneal injection of 40 ml/kg isotonic saline solution and subcutaneous injection of 3 units/kg insulin were given to the rats in treatment group after being subjected to 30% TBSA full-thickness burns. Subcutaneous injection of equal amount of isotonic saline was given to the sham and burn groups. The changes in vascular endothelial cell structure were observed with electron microscopy at 24 post-scald hours(PSH). Meanwhile, the blood glucose contents, the serum levels of nitric oxide (NO) and nitric oxide synthetase (NOS) were determined with oxidase method and colorimetric method, respectively.

RESULTSThe injury of arterial endothelial cells in the treatment group was obviously alleviated compared with that in burn group. The blood glucose content in the treatment group (7.1 +/- 0.7 mmol/L) was significantly lower than that in scald group (8.2 +/- 1.0 mmol/L, P < 0.05), though it was much higher in both groups than that in sham scald group (4.9 +/- 0.8 mmol/L, P < 0.01) at 24 PBH. The serum content of NO, total NOS and cNOS in treatment group were obviously higher than those in scald group (P < 0.01), but there was no obvious difference in iNOS content between the two groups(P > 0.05).

CONCLUSIONInsulin exhibits protective effect on vascular endothelial cells in severely scalded rats at the early post-burn stage, and it is attributed to its promotion of cNOS level leading to NO production.

Animals ; Blood Glucose ; analysis ; Burns ; blood ; drug therapy ; pathology ; Disease Models, Animal ; Endothelial Cells ; drug effects ; pathology ; Insulin ; therapeutic use ; Male ; Nitric Oxide ; blood ; Nitric Oxide Synthase ; blood ; Random Allocation ; Rats ; Rats, Sprague-Dawley