Upregulation of MAOA in the hippocampus results in delayed depressive-like behaviors in burn mice

OBJECTIVE

To observe depressive-like behavior and hippocampus monoamine oxidase A (MAOA) changes in burned mice.

METHODS

We tested depression and anxiety like behaviors of burn C57 mice with the sucrose preference test, forced swimming test (FST), open field test and elevated plus maze test and then detected the MAOA content and MAOA gene transcriptional levels in the hippocampus with western blot analysis and real-time quantitative PCR analysis. We then sought to reverse depressive-like behavior of burned mice with an MAOA inhibitor.

RESULTS

(1) Mice showed depressive and anxiety like behaviors one week after they were burned; (2) The content of MAOA in the hippocampus of burned mice was significantly higher than that in control mice (P<0.05); (3) MAOA gene transcription in the hippocampus of burned mice was significantly increased (MAOA mRNA was increased, P<0.05); (4) treatment with a MAOA inhibitor (phenelzine) significantly increased the sucrose preference rate and decreased FST immobility time in burned mice, and also decreased elevated expression of MAOA in the hippocampus of burned mice.

CONCLUSION

Burned mice showed "delayed" depressive-like behavior combined with a degree of anxiety; this phenomenon is likely associated with the increase in MAOA expression in the hippocampus.

[A case of multiple difficult illnesses in a patient with extremely severe burn complicated with type 2 diabetes]

On December 20, 2018, a 40-year-old male patient with extremely severe flame burn was admitted to Guangzhou First People's Hospital. A variety of difficult illnesses occurred simultaneously (refractory hyperglycemia, refractory hypernatremia, and progressive wound deepening) and successively (repeatedly postoperative hypotension, nervous system diseases, and secondary diabetes insipidus). The patient underwent treatments such as anti-shock, reducing blood sugar and blood sodium, scab removing, and gradual skin grafting after admission. Although the hyperglycemia and hypernatremia were basically corrected and the wounds were basically repaired, the patient ultimately died of nervous system diseases and secondary diabetes insipidus 5 months later. Although the cause of the above illnesses can not be fully determined, the targeted treatments to improve clinical symptoms, maintain stable internal environment and physiological function, and accelerate the process of wound repair conducted by the team may provide some experience for the treatment of such severe patients.

[Biologic effects of different concentrations of putrescine on human umbilical vein endothelial cells]

OBJECTIVE

To explore the effects of different concentrations of putrescine on proliferation, migration, and apoptosis of human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were routinely cultured in vitro. The 3rd to the 5th passage of HUVECs were used in the following experiments. (1) Cells were divided into 500, 1 000, and 5 000 µg/mL putrescine groups according to the random number table (the same grouping method was used for following grouping), with 3 wells in each group, which were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h. Morphology of cells was observed by inverted optical microscope. (2) Cells were divided into 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups, and control group, with 4 wells in each group. Cells in the putrescine groups were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h, and cells in control group were cultured with complete culture solution with no additional putrescine for 24 h. Cell proliferation activity (denoted as absorption value) was measured by colorimetry. (3) Cells were divided (with one well in each group) and cultured as in experiment (2), and the migration ability was detected by transwell migration assay. (4) Cells were divided (with one flask in each group) and cultured as in experiment (2), and the cell apoptosis rate was determined by flow cytometer. Data were processed with one-way analysis of variance, Kruskal-Wallis test, and Dunnett test.

RESULTS

(1) After 24-h culture, cell attachment was good in 500 µg/mL putrescine group, and no obvious change in the shape was observed; cell attachment was less in 1 000 µg/mL putrescine group and the cells were small and rounded; cells in 5 000 µg/mL putrescine group were in fragmentation without attachment. (2) The absorption values of cells in 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups, and control group were respectively 0.588 ± 0.055, 0.857 ± 0.031, 0.707 ± 0.031, 0.662 ± 0.023, 0.450 ± 0.019, 0.415 ± 0.014, 0.359 ± 0.020, 0.204 ± 0.030, and 0.447 ± 0.021, with statistically significant differences among them (χ(2) = 6.86, P = 0.009). The cell proliferation activity in 0.5, 1.0, 5.0, and 10.0 µg/mL putrescine groups was higher than that in control group (P < 0.05 or P < 0.01). The cell proliferation activity in 500.0 and 1 000.0 µg/mL putrescine groups was lower than that in control group (with P values below 0.01). The cell proliferation activity in 50.0 and 100.0 µg/mL putrescine groups was close to that in control group (with P values above 0.05). (3) There were statistically significant differences in the numbers of migrated cells between the putrescine groups and control group (F = 138.662, P < 0.001). The number of migrated cells was more in 1.0, 5.0, and 10.0 µg/mL putrescine groups than in control group (with P value below 0.01). The number of migrated cells was less in 500.0 and 1 000.0 µg/mL putrescine groups than in control group (with P value below 0.01). The number of migrated cells in 0.5, 50.0, and 100.0 µg/mL putrescine groups was close to that in control group (with P values above 0.05). (4) There were statistically significant differences in the apoptosis rate between the putrescine groups and control group (χ(2)=3.971, P=0.046). The cell apoptosis rate was lower in 0.5, 1.0, 5.0, and 10.0 µg/mL putrescine groups than in control group (with P values below 0.05). The cell apoptosis rate was higher in 500.0 and 1 000.0 µg/mL putrescine groups than in control group (with P values below 0.01). The cell apoptosis rates in 50.0 and 100.0 µg/mL putrescine groups were close to the cell apoptosis rate in control group (with P values above 0.05).

CONCLUSIONS

Low concentration of putrescine can remarkably enhance the ability of proliferation and migration of HUVECs, while a high concentration of putrescine can obviously inhibit HUVECs proliferation and migration, and it induces apoptosis.

[Effects of different concentrations of putrescine on proliferation, migration and apoptosis of human skin fibroblasts]

OBJECTIVE

To explore the effects of different concentrations of putrescine on the proliferation, migration and apoptosis of human skin fibroblasts (HSF).

METHODS

HSF cultured in the presence of 0.5, 1.0, 5.0, 10, 50, 100, 500, and 1000 µg/ putrescine for 24 h were examined for the changes in the cell proliferation, migration, and apoptosis using MTS assay, Transwell migration assay, and flow cytometry, respectively.

RESULTS

Compared with the control cells, HSF cultured with 0.5, 1.0, 5.0, and 10 µg/ putrescine showed significantly increased cell proliferation (P<0.01), and the effect was the most obvious with 1 µg/ putrescine, whereas 500 and 1000 µg/ putrescine significantly reduced the cell proliferation (P<0.01); 50 and 100 µg/ did not obviously affect the cell proliferation (P>0.05). Putrescine at 1 µg/ most significantly enhanced the cell migration (P<0.01), while at higher doses (50, 100, 500, and 1000 µg/) putrescine significantly suppressed the cell migration (P<0.05); 0.5, 5.0, and 10 µg/ putrescine produced no obvious effects on the cell migration (P>0.05). HSF treated with 0.5, 1.0, 5.0, and 10 µg/ putrescine obvious lowered the cell apoptosis rate compared with the control group (P<0.01), and the cell apoptosis rate was the lowest in cells treated with 1 µg/ putrescine; but at the concentrations of 100, 500, and 1000 µg/, putrescine significantly increased the cell apoptosis rate (P<0.01), while 50 µg/ml putrescine produced no obvious effect on cell apoptosis (P>0.05).

CONCLUSION

Low concentrations of putrescine can obviously enhance the proliferation ability and maintain normal migration ability of HSF in vitro, but at high concentrations, putrescine can obviously inhibit the cell migration and proliferation and induce cells apoptosis, suggesting the different roles of different concentrations of putrescine in wound healing.

[Influence of exogenous putrescine on the function of liver and apoptosis of liver cells in rats]

OBJECTIVE

To explore the influence of exogenous putrescine on the function of liver and apoptosis of liver cells in rats.

METHODS

Ninety healthy clean SD rats were divided into control group (C, n = 10, intraperitoneally injected with 2 mL normal saline), low dosage putrescine group (LP, n = 40), and high dosage putrescine group (HP, n = 40) according to the random number table. Rats in the latter two groups were intraperitoneally injected with approximately 2 mL putrescine (2.5 or 5.0 g/L) with the dosage of 25 or 50 µg/g. Ten rats from group C at post injection hour (PIH) 24 and 10 rats from each of the latter two groups at PIH 24, 48, 72, 96 were sacrificed. Heart blood was obtained for determination of serum contents of ALT and AST. Liver was harvested for gross observation and histomorphological observation with HE staining. Apoptosis was shown with in situ end labeling, and apoptosis index (AI) was calculated. Data among the three groups and those at different time points within one group were processed with one-way analysis of variance or Welch test; LSD or Dunnett's T3 test was used for paired comparison; factorial design analysis of variance of two factors was applied for data between group LP and group HP.

RESULTS

(1) No obvious abnormality was observed at gross observation of liver of rats in each group. Liver tissue of rats in group C was normal. Light edema was observed occasionally in liver of rats in groups LP and HP, but necrotic cells were not seen. (2) Content of ALT at PIH 24, 48, 96 and content of AST at PIH 72 and 96 in group LP were respectively (38 ± 10), (45 ± 6), (34 ± 4), (207 ± 18), (196 ± 19) U/L, and content of ALT at PIH 72 and 96 and content of AST at PIH 24, 72, 96 in group HP were respectively (38 ± 6), (48 ± 5), (213 ± 43), (209 ± 40), (230 ± 29) U/L. They were significantly higher than those of rats in group C [(29 ± 5), (163 ± 42) U/L, with P values all below 0.01]. There were statistically significant differences between group LP and group HP in the content of ALT at PIH 48, 72, 96 and content of AST at PIH 96 (with P values all below 0.05). Compared with that at PIH 24 of each group, content of ALT of rats in group LP at PIH 48 and that of rats in group HP at PIH 96, as well as content of AST of rats in group LP at PIH 48, 72, 96 and that of rats in group HP at PIH 48 were significantly increased or decreased (with P values all below 0.05). Factorial analysis showed that the differences due to different concentration of putrescine on content of AST were statistically significant (F = 12.21, P = 0.001), but not on content of ALT (F = 0.01, P = 0.974) between group LP and group HP. (3) AI values of rats in group LP at PIH 24, 48, 72 were respectively (5.69 ± 0.38)%, (13.80 ± 1.66)%, (11.56 ± 1.74)%, and AI values of rats in group HP at PIH 72 and 96 were respectively (10.29 ± 1.43)%, (15.29 ± 1.41)%. They were all obviously higher than AI value of control group at PIH 24 [(3.50 ± 0.30)%, with P values all below 0.01]. There were statistically significant differences between group LP and group HP in AI value at PIH 24, 48, 96 (with P values all below 0.05). Compared with that at PIH 24 of each group, AI value of rats in groups LP and HP at PIH 48, 72, 96 were significantly increased or decreased (with P values all below 0.05). Factorial analysis showed that the differences in the influence of concentration of putrescine and stimulation time on AI value were statistically significant (with F values respectively 22.95 and 130.44, P values all below 0.01).

CONCLUSIONS

Intraperitoneal injection of exogenous putrescine in the dosage of 25 or 50 µg/g could lead to certain degree of functional damage of liver and apoptosis of liver cells of rat. The higher the dosage and the longer the stimulation time, the more obvious the damage and apoptosis would be.

[Determination and correlation analysis of contents of putrescine, cadaverine, and histamine in necrotic tissue, blood, and urine of patients with diabetic foot]

OBJECTIVE

To determine and perform a correlation analysis of the contents of putrescine, cadaverine, and histamine in necrotic tissue, blood, and urine of patients with diabetic foot (DF).

METHODS

Ten patients with severe wet necrotizing DF hospitalized from January 2011 to January 2012 were assigned as group DF, and 10 orthopedic patients with scar but without diabetes or skin ulcer hospitalized in the same period were assigned as control group. Samples of necrotic tissue from feet of patients in group DF and normal tissue from extremities of patients in control group, and samples of blood and 24-hour urine of patients in both groups were collected, and the amount of each sample was 10 mL. Contents of putrescine, cadaverine, and histamine were determined with high performance liquid chromatography-mass spectrometry. The data got from the determination of blood and urine were processed with t test, and those from necrotic or normal tissue with Wilcoxon rank sum test. The correlation of contents of polyamines between necrotic tissue and blood, blood and urine were processed with simple linear regression analysis.

RESULTS

(1) Contents of putrescine, cadaverine, and histamine in the necrotic tissue of group DF were (186.1 ± 26.8), (78.553 ± 12.441), (33 ± 10) mg/kg, which were significantly higher than those in normal tissue of control group [(2.2 ± 1.2), (1.168 ± 0.014), 0 mg/kg, with Z values respectively -3.780, -3.781, -4.038, P values all below 0.01]. The content of putrescine in necrotic tissue of group DF was significantly higher than those of cadaverine and histamine (with Z values respectively -3.780, -3.630, P values all below 0.01). (2) Contents of putrescine, cadaverine, and histamine in the blood of group DF were (0.075 ± 0.013), (0.022 ± 0.003), (0.052 ± 0.014) mg/L, and they were significantly higher than those in the blood of control group [(0.014 ± 0.009), (0.013 ± 0.003), (0.016 ± 0.008) mg/L, with t values respectively 6.591, 2.207, 3.568, P < 0.05 or P<0.01]. The content of putrescine in the blood of group DF was significantly higher than those of cadaverine and histamine (with t values respectively 13.204, 3.096, P values all below 0.01). (3) Contents of putrescine, cadaverine, and histamine in the urine of group DF were (0.735 ± 0.088), (0.450 ± 0.012), (0.1623 ± 0.0091) mg/L, and only the contents of putrescine and cadaverine were significantly higher than those in the urine of control group [(0.050 ± 0.014), (0.035 ± 0.007) mg/L, with t values respectively 3.270, 4.705, P<0.05 or P<0.01]. The content of putrescine in the urine of group DF was significantly higher than that of cadaverine (t = 6.686, P < 0.01). (4) There were significant and positive correlations in contents of putrescine, cadaverine, and histamine between necrotic tissue and blood in patients of group DF (with r values respectively 0.981, 0.994, 0.821, P values all below 0.01). There were no significant correlations in contents of putrescine, cadaverine, and histamine between blood and urine in patients of group DF (with r values respectively 0.150, 0.239, 0.177, P values all above 0.05).

CONCLUSIONS

Putrescine, cadaverine, and histamine exist in the necrotic tissue of patients with DF in high concentrations, among which putrescine predominates. These polyamines can be absorbed into the blood through wound and excreted through the urine.

[Effect of mannitol on serum tumor necrosis factor-α and interleukin-6 levels and the mechanism of its organ-protective effect in rabbits early after severe burn injury]

OBJECTIVE

To investigate the protective effect of mannitol therapy on the vital organs and explore the underlying mechanisms in New Zealand rabbits with severe burn injury.

METHODS

Twelve New Zealand rabbits with severe burn injury (30% of TBSA) were randomized to receive fluid resuscitation with saline (control) or mannitol therapy starting at 1 h after the injury. Serum and urine samples were collected before and at 1, 4, 8, 24, and 48 h after the injury for detection of TNF-α, IL-6, ALT, AST, GGT, CK, CK-MB, BUN and Cr levels using sandwich ELISA.

RESULTS

One hour after sever burn injury, the serum levels of TNF-α and IL-6 began to increase along with ALT, AST, GGT, CK, CK-MB, BUN and Cr levels. Compared with control group, the rabbits in mannitol group showed significantly higher 48 h urine excretion of TNF-α (145 ± 8 vs 78 ± 1 0 pg/ml, P<0.05) and IL-6 (93 ± 6 vs 40 ± 8 pg/ml, P<0.05) but with lowered serum levels of TNF-α (0.62 ± 0.02 vs 0.83 ± 0.02 pg/ml, P<0.05) and IL-6 (0.45 ± 0.03 vs 0.56 ± 0.03 pg/ml, P<0.05) as well as lowered serum ALT, AST, GGT, CK, CK-MB, BUN and Cr levels (P<0.05).

CONCLUSION

In rabbits with severe burn injury, mannitol therapy can decrease serum TNF-α and IL-6 levels early after the injury to ameliorate potential functional impairment of the heart, liver and kidneys.

[Influence of exogenous putrescine and cadaverine on pro-inflammatory factors in the peripheral blood of rabbits]

OBJECTIVE

To explore the influence of exogenous putrescine and cadaverine on pro-inflammatory factors in the peripheral blood of rabbits.

METHODS

Forty ordinary adult New Zealand rabbits were divided into saline, necrotic tissue homogenate (NTH), putrescine, and cadaverine groups according to the random number table, with 10 rabbits in each group. Saline, NTH, 10 g/L putrescine, and 10 g/L cadaverine were respectively peritoneally injected into rabbits of corresponding group in the amount of 1 mL/kg. The blood sample in the volume of 2 mL was collected from the central artery of rabbit ears before injection and at 2, 6, 12, 24, 30, 36, 48, 60 hours post injection (PIH). Contents of TNF-α, IL-1, and IL-6 in the serum were determined with enzyme-linked immunosorbent assay. Data were processed with repeated measurement data analysis of variance and Spearman correlation analysis, and cubic model curve was applied in curve fitting for the contents of inflammatory factors.

RESULTS

(1) The serum contents of TNF-α, IL-1, and IL-6 were increased in NTH, putrescine, and cadaverine groups in different degrees at most post injection time points. There was no significant change in the concentrations of the three pro-inflammatory factors in saline group, and they were significantly lower than those of the other three groups at most post injection time points (with F values from 3.49 to 13.58, P values all below 0.05). The serum contents of TNF-α, IL-1, and IL-6 in putrescine group began to increase at PIH 2, 6, and 6, which was similar to the trend of NTH group, but the changes were delayed compared with those of cadaverine group(all at PIH 2). The peak values of TNF-α, IL-1, and IL-6 in putrescine group were respectively (339 ± 36), (518 ± 44), and (265.9 ± 33.5) pg/mL, which were significantly lower than those of cadaverine group [ (476 ± 86), (539 ± 22), and (309.4 ± 27.1) pg/mL], with F values respectively 5.11, 1.90, and 5.56, P values all below 0.05. (2) The period of time in which contents of TNF-α, IL-1, and IL-6 began to increase (PIH 3-4) and the peaking time of the three pro-inflammatory cytokines (PIH 18-30) in putrescine group appeared later than those of cadaverine group (PIH 2 and 12-30). The duration of peaking time of the three pro-inflammatory cytokines in putrescine group was shorter than that of cadaverine group (PIH 18-30 vs. PIH 12-30). The increasing period and the duration of peaking time of TNF-α, IL-1, and IL-6 in putrescine group were close to those of NTH group (PIH 3-5 and 18-30). The correlation coefficient test analysis showed that the trends of changes in contents of three pro-inflammatory cytokines in putrescine group were significantly correlated with those of NTH group (r(TNF-α) = 0.933, P < 0.01; r(IL-1) = 0.967, P < 0.01; r(IL-6) = 0.950, P < 0.01). The obvious correlation between cadaverine group and NTH group was only found in the contents of IL-1 and IL-6 (r(IL-1) = 0.913, P < 0.01; r(IL-6) = 0.883, P < 0.05).

CONCLUSIONS

Both exogenous putrescine and cadaverine can cause inflammatory reaction in rabbits. The trend of the inflammatory reaction induced by putrescine was similar with that by NTH, suggesting that putrescine may play a leading role in the inflammatory reaction induced by necrotic tissue decomposition.

[Exogenous putrescine causes renal function impairment and cell apoptosis in rats]

OBJECTIVE

To explore the effect of exogenous putrescine on renal function and cell apoptosis in rats.

METHODS

Ninety SD rats were randomized into control group (n=10), high-dose putrescine group (P1 group, n=40), and low-dose putrescine group (P2 group, n=40) with intraperitoneal injections of 2 ml of normal saline, 50 µg/g putrescine, and 25 µg/g putrescine, respectively. At 24, 48, 72 and 96 h after the injections, 10 rats from each group were sacrificed to examine serum Cr and BUN levels, histological changes in the kidneys, and renal cell apoptosis (TUNEL assay).

RESULTS

The rats in the two putrescine- treated groups showed mild edema in some renal tissues without obvious necrosis. In P1 and P2 groups, serum Cr and BUN levels differed significantly at each time point of measurement (P<0.01 and P<0.05, respectively), and were significantly higher than the levels in the control group (P<0.01 and P<0.05, respectively). The two putrescine-treated groups showed gradually increased renal cell apoptosis with time, reaching the peak levels at 96 h and 48 h, respectively. The peak renal cell apoptosis rates in P1 [(24.78∓2.19)%] and P2 [(26.27∓2.13)%] group were significantly higher than the rate in the control group [(4.47∓0.33)%, P<0.01].

CONCLUSION

Exogenous putrescine can lead to renal function impairment and induce renal cell apoptosis in rats, and the severity of these changes appeared to be associated with the blood concentration of exogenous putrescine.

[Effect of necrotic wound tissue decomposition products on serum inflammation factors in rabbits]

OBJECTIVE

To observe the effect of the decomposition products of necrotic tissues from wounds on the serum levels of inflammation factors in comparison with endotoxin.

METHODS

Thirty adult New Zealand rabbits were randomly divided into 3 groups and received injections of saline, necrotic tissue homogenate or endotoxin. From each rabbit, blood samples (2 ml) were collected from the central artery of the ears at 0, 2, 6, 12, 24, 30, 36, 48, and 60 h after the injection for measurement of serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1) and IL-6.

RESULTS

The serum level of TNF-α, IL-1 and IL-6 in the rabbits increased 2-4 h after injection of the necrotic tissue homogenate and reached the peak level at 12 h, followed by a gradual reduction since 36 h. No obvious changes in the levels of the inflammatory factors were found in saline group (P<0.01). Compared with endotoxin, necrotic tissue homogenate resulted in an early increment (2-4 h vs 5-6 h) and significantly higher peak levels (at 30 h) of the inflammation factors (P<0.05). Curve fitting showed a distinct difference between necrotic tissue homogenate and endotoxin in their effect on the inflammatory factors.

CONCLUSION

The necrotic tissue decomposition products contain toxic substances that possess a different toxicity profile from endotoxin, and their toxicity can be even stronger.

[Absorption of albumin in subeschar tissue fluid in early stage after burn in rabbit and its pharmacokinetics]

OBJECTIVE

To observe the change in albumin concentration in the subeschar tissue fluid of rabbits in early stage after burn, and to analyze its regular pattern.

METHODS

Thirty-four adult male New Zealand rabbits were divided into control group and experiment group according to the random number table, with 17 rabbits in each group. Rabbits in experiment group were subjected to 8% TBSA full-thickness scald on the back and were injected with human serum albumin in subeschar tissue serving as tracing albumin. 1.5 mL blood sample was collected at post scald hour (PSH) 2, 4, 8, 16, 24, 48, 72 respectively. Rabbits in control group were dealt with the above-mentioned procedures except for scald. The concentration of tracing albumin was measured with the enzyme-linked immunosorbent assay kit. The concentration of the serum albumin of rabbits were determined with biochemical analyzer. Pharmacokinetics parameters of tracing albumin were calculated with fitting model of 3P97 practical pharmacokinetics calculating program.

RESULTS

(1) Concentration of tracing albumin of rabbits in experiment group was respectively higher than that in control group (P < 0.01) at each time point, and it peaked at PSH 8 [(421 +/- 10) microg/L]. (2) The concentration of serum albumin of rabbits in experiment group decreased in the beginning and increased later, while no significant change was observed in control group. (3) The distribution phase half-life of tracing albumin of rabbits in experiment group (4.0271 h) was about 1/3 of that of the control group (12.0907 h); while the area under the curve in the experiment group (22 336.38 microg.h.mL(-1)) was about 4 times of that in the control group (5827.77 microg.h.mL(-1)).

CONCLUSIONS

The albumin in the subcutaneous tissue could be absorbed into blood circulation in normal conditions. The resorption occurs earlier and faster and more when obvious inflammation occurs (such as deep burn). Exudation and resorption of albumin co-exist in the early stage after burn.

[Distribution and drug resistance analysis of bacteria in different wound infections]

OBJECTIVE

To analyze the distribution and drug resistance of bacteria in different wound infections and provide evidence for wound infection control in subtropical regions.

METHODS

This study involved 265 patients from 4 different departments of our hospital who experienced wound infections between July, 2007 and July, 2008. The bacterial strain distribution in the wounds and drug resistance of the bacteria were analyzed.

RESULTS

Acinetobacter baumanii (39% of the total strain identified) was the most frequent bacterial strain causing infection of the burn wounds, followed by Proteus mirabilis (20%) and Pseudomonas aeruginosa (20%). E. coli infection was prevalent in the departments of general surgery (37%) and urinary surgery (64%), and Pseudomonas aeruginosa and Pseudomonas pneumonia infections were detected at the rate of 30% and 43% in the urinary surgery department, respectively. Different bacterial strains were found at similar rates around 10% in the wounds of patients undergoing traumatic surgery.

CONCLUSION

Despite that the commonly seen pathogenic bacteria in burn patients including Staphylococcus aureus have been effectively controlled by early application of antibiotics, the opportunistic pathogens such as Acinetobacter baumanii and Proteus mirabilis often survive these antibiotics, and some strains evolve to be drug-resistant and even multi-drug-resistant. E. coli infection is prevalent in general surgery and urinary surgery departments, where Staphylococcus aureus and Pseudomonas aeruginosa infections can also be found frequently. All kinds of bacteria infection are present in trauma surgery department, each found at the rate around 10%.

[Effect of intralipid for ameliorating protein loss in severe burned patients]

OBJECTIVE

To investigate the effect of intralipid on protein consumption in severe burned patients. METHODS; Sixty-seven nonoperative patients with severe burns were divided into Intralipid treatment group and non-intralipid treatment group (control group), and the former was treated with 20% intralipid (500 ml once a day) from postburn day 4 for 10 consecutive days. Venous blood samples were collected from these patients for testing total protein, albumin, total cholesterol and triglyceride on postburn days 1, 7 and 14, respectively.

RESULTS

The levels of total protein, albumin, total cholesterol and triglyceride were within normal range on postburn day 1 in both groups, and only the albumin level was lowered in the groups on day 7 but at comparable magnitudes (32+/-4.83 vs 31+/-5.04 g/L, P<0.05). In contrast, the levels of total protein, albumin, total cholesterol and triglyceride were below the normal range on postburn day 14 in both groups, but intralipid treatment group showed more albumin loss than the control group (28+/-6.46 vs 23+/-7.03 g/L, P<0.01).

CONCLUSION

Intralipid (20%) provides good energy source to ameliorate albumin loss in severe burned patients.

[Effect of asiaticoside on the expression of transforming growth factor-beta mRNA and matrix metalloproteinases in hypertrophic scars]

OBJECTIVE

To investigate the effect of asiaticoside on the expressions of transforming growth factor (TGF)-beta mRNA, matrix metalloproteinases (MMPS) and tissue inhibitors of metalloproteinases (TIMPs) in postburn hypertrophic scars.

METHODS

Nine specimens of postburn (5-8 months) hypertrophic scars with asiaticoside treatment and 9 without asiaticoside treatment were collected for testing the expressions of MMPS, TIMPs, type I and III collagen and TGF-beta mRNA by immunohistochemistry and in situ hybridization methods, followed by image analysis of the results.

RESULTS

The expressions of TGF-beta mRNA and MMPS/TIMPS were all detected in the fibroblast cytoplasm. The expression of TGF-beta(1) mRNA in asiaticoside-treated scars was significantly lower than that in scars without asiaticoside treatment (P<0.01). In contrast, the expression of TGF-beta(3) mRNA was significantly higher in asiaticoside group (P<0.05). The expression of TIMP1 in asiaticoside group was significantly lower than that in non-asiaticoside group (P<0.01), and the expression of type I collagen in asiaticoside-treated scars was lower than that in non-asiaticoside-treated specimens (P<0.05), but the expression of MMP(1), MMP(2) and TIMP(2) and type III collagen exhibited no significant differences between the two groups (P>0.05).

CONCLUSION

Asiaticoside can down-regulate TGF-beta(1) mRNA and TIMP(1) expressions and up-regulate TGF-beta(3) mRNA expression in postburn hypertrophic scars, and is also capable of decomposing the products of type I collagen, contributing to the reduction of hypertrophic scar formation.

[Morphological changes in intestinal villi after severe burns in rats]

OBJECTIVE

To investigate the morphological changes in intestinal villi after severe burns in rats, so as to explore its possible relationship with enteral bacterial translocation.

METHODS

Fifty Wistar rats were employed in the study, 10 of them were assigned to the control group (C). The rest 40 rats were subjected to 30% TBSA full-thickness scalding (burn group, B). 4 ml/100 g normal saline was given intra-peritoneally to the injured rats. The changes of the caliber of the central chyliferous vessel, the intestinal water content and the mucosal morphology of the terminal ileum were determined in the rats in C group and in B group at 8, 12, 24 and 48 postburn hours. The morphology of villi was observed with scanning electron microscope and light microscope.

RESULTS

The ileal villi appeared normal in C group. The central chyliferous vessel dilated persistently in rats of B group at all postburn time points, and dilatation was more evident in B group compared with control group (P < 0.01). At the same time an abundant amount of lymph was observed in the central chyliferous vessel. The intestinal water contents decreased to (70.5 +/- 2.2)% and (69.5 +/- 3.1)% in rats of B group at 8 and 12 PBHs, respectively, and they were obviously lower than that in C group (76.9 +/- 1.5)%, (P < 0.01). The intestinal water content in B group was similar to that in C group at 24 and 48 PBH (P > 0.05).

CONCLUSION

The morphological changes in the intestinal villi of rats with severe burn injury may predispose the invasion of enteral toxin and bacteria. Intestinal lymphatics can be an important route for enteral bacterial translocation. The water reabsorption of the intestinal mucosa can be transiently enhanced during early postburn stage.

[Changes in proinflammatory cytokines and immune function of subeschar tissue fluid during early stage after severe burn]

OBJECTIVE

To evaluate the inflammatory response and immune function of subeschar tissue fluid (STF) in early stage of severe burn.

METHODS

Eight patients were observed and samples from blood as well as STF were collected at 16, 24, 32, 40, 48 hours following burn to measure white blood cell (WBC) counts, levels of immunoglobin (IgA, IgG, IgM), complement (C3, C4) values as well as proinflammatory cytokines as tumor necrosis factor-alpha (TNF-alpha), interleukin-6(IL-6) and IL-8. In addition, twenty Balb-c mice were used for the lethal experiment by STF collected at 48 hours after burn.

RESULTS

The levels of IgA, IgG, IgM in STF were about half of those in the blood samples (all P<0.01). The WBC counts in STF were 1/100 time of that in the blood (all P<0.01). The contents of TNF-alpha, IL-6 and IL-8 in STF were comparable with those in the blood (P>0.05). Following STF challenge, none of the mice died during 7-day observation period.

CONCLUSION

The cells and large molecules seems to be more difficult to enter STF compared with small molecules. No marked local inflammatory response occurs in STF during early stage of severe burn, and STF challenge has no lethal effect. The low WBC counts and low immunoglobin as well as complement levels imply the limited effect of STF on local infection, and effective antibiotics should be timely used after major burn.

An experimental study on systemic inflammatory response syndrome induced by subeschar tissue fluid

OBJECTIVE

To investigate the biological activity of subeschar tissue fluid (STF) and its probable mechanism in the genesis of systemic inflammatory response syndrome(SIRS).

METHODS

The changes of heart rate (HR), respiratory rate (RR), white blood cell count (WBCC) as well as the major organ function were observed in the animals injected with STF. The inflammatory mediators TNF-alpha and IL-1 in the supernatants of macrophages cultured with STF were assayed.

RESULTS

The HR, RR and WBCC were elevated in animals after injection with STF. STF showed a deleterious effect on function and structure of the major visceral organs. Macrophages were activated to produce excessive TNF-alpha and IL-1.

CONCLUSION

The findings suggest that STF may be one of the inducing factors involved in the genesis of SIRS and the development of MODS in the early postburn stage.

Successful recovery of 14 patients afflicted with full-thickness burns for more than 70 per cent body surface area

Fourteen cases suffering full-thickness burns of more than 70 per cent total body surface area (TBSA) have been successfully treated during the last 8 years (1988-1995). Among these patients, 10 cases suffered from burns of more than 90 per cent TBSA. Five cases had full-thickness burns of 80-90 per cent TBSA. Escharectomy, followed by coverage of wounds with a homograft to the lower surface of which, adjacent to the wound bed, microautoskin grafts had been attached was employed to close wounds in the early stages after burn. The remaining non-surgically treated wound was treated by exposure and topical silver sulfadiazine. The temperature and humidity of the ward was controlled by air conditioning and dehumidification. Aggressive excision of eschar and auto-skingrafting was carried out 3 weeks post-injury. Strictly limiting the uncovered wound to less than 5 per cent appeared to be the major effective measure in preventing burn infection.

[Experimental study of pulmonary infection and its systemic dissemination in the early stage of severe burn]

A total of 138 rabbits were used for the study of pulmonic infection and systemic dissemination in early stage of severe burns. One group of animals was inflicted with third degree burns on the back covering 20% of total body surface area; coincidently an intratracheal introduction of sero-type IX pseudomonas aeruginosa (IXPA) were performed. Above group of animals were compared with the simple body surface burns, simple intratracheal colonization and amikacin treatment groups. For observation, a series of blood samples, swabs of throat were taken at regular times for bacterial culture and IXPA identification. Endotoxin levels of blood plasma were measured too. Animals were killed at 8, 16, 24, 72 hours post-injury, tissue specimens of lung, liver, spleen and kidney were taken for quantitative bacterial cultures, and lung tissues for histological examination. The results showed that the predominant colonization of IXPA in the throats in burned animals are more difficult to be eliminated than that of in non-burned ones. The susceptibility of drugs to IXPA in burned group is higher than that of in control groups, with more severe tissue damages under microscopic examination. The pathogen of pulmonary infection began to invade into the blood stream at four hours post-injuries, and multiple organs dissemination occurred, in which the livers and kidneys were primarily affected. Coincidently a process of endotoxemia was proved. The systemic use of sensitive antibiotics immediately after burns showed benefit to decrease the rate of bacteremia and dissemination of other organs, as well as the rate of death.