[Efficacy of fenofibrate for hepatic steatosis in rats after severe burn].

OBJECTIVE: To observe the efficacy of fenofibrate for hepatic steatosis in rats after severe burn. METHODS: Twenty-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). CONCLUSIONS: Fenofibrate can ameliorate the dyslipidemia of severely burned rat, and it can alleviate the degree of hepatic steatosis in certain degree.

[Effects of sodium tanshinone II A sulfonate on proliferation of fibroblasts in scar and the mRNA and protein expressions of transforming growth factor beta 1 and alpha smooth muscle actin].

OBJECTIVE: To study the effects of sodium tanshinone II A sulfonate (STS) on proliferation of fibroblasts (Fbs) in human hypertrophic scar (HS), the mRNA and protein expressions of transforming growth factor beta 1 (TGF-ß1) and alpha smooth muscle actin (α-SMA), and to investigate the scar inhibition mechanism of STS. METHODS: Fbs were isolated from HS tissues that were removed from eight patients after burn injury, and they were cultured in vitro. Cells from the 3rd to the 6th passages were used in the experiment. Fbs were divided into control group and experimental group according to the random number table, and cells in the experimental group was divided into 0.050, 0.075, 0.100, 0.125, 0.150, 0.200 mg/mL STS subgroups. Cells in each subgroup were cultured with the corresponding concentration of STS, and cells in control group were cultured in equal volume of serum-free medium. After being cultured for 24 and 48 h, cell morphology was observed with inverted phase contrast microscope; cell proliferation was determined with MTT method and the proliferation inhibition rate (IR) was calculated. After being cultured for 48 h, the protein levels of TGF-ß1 and α-SMA were determined with Western blotting; the mRNA expressions of TGF-ß1 and α-SMA were determined with RT-PCR (no 0.200 mg/mL STS subgroup was set for these two indicators). Data were processed with factorial analysis of variance; differences between groups were processed with LSD test or Games-Howell test for unequal variances. RESULTS: (1) Fbs grew well in control group, but reduction in adherence and disorderly arranged Fbs were observed in experimental group. The cells in experimental group became smaller and round, with increasing intracellular particles and necrosis. A large amount of necrotic debris of cells was observed in 0.200 mg/mL STS subgroup. (2) The absorbance value of Fbs in each experimental subgroup was significantly lower than that in control group (with P values all below 0.01). Along with the increase in the concentration of STS and extension of culture time, the IR value increased, showing a certain degree of time-concentration dependence. After being cultured with STS for 24 and 48 h, IR values of cells in the experimental subgroups were respectively 23.58%, 32.11%, 37.56%, 57.98%, 79.53%, 96.69% and 34.72%, 38.48%, 47.62%, 64.40%, 89.70%, 98.01%. (3) Except for the 0.050 mg/mL STS subgroup, the protein levels of TGF-ß1 and α-SMA in the other subgroups were significantly lower than those in control group (with F values respectively 57.674, 47.795, P values all below 0.001). The protein levels of TGF-ß1 and α-SMA reached the nadir in 0.150 mg/mL STS subgroup, respectively 0.34 ± 0.06, 0.33 ± 0.07. The relative expression amounts of TGF-ß1 and α-SMA mRNA in the experimental subgroups were obviously decreased compared with those in control group (with F values respectively 68.548, 47.522, P values all below 0.001), which was most significant in 0.150 mg/mL STS subgroup, with TGF-ß1 mRNA and α-SMA mRNA respectively 0.39 ± 0.07 and 0.42 ± 0.08. CONCLUSIONS: STS can inhibit the proliferation of Fbs, reduce the protein and mRNA expressions of TGF-ß1 and α-SMA, which may be beneficial to ameliorate the formation and contracture of HS, and it is assumed as a potential drug for treating scars.

Beneficial effects of insulin on cell proliferation and protein metabolism in skin donor site wound.

BACKGROUND: Insulin has been demonstrated to accelerate skin wound healing; however, its effects on wound metabolism have not been adequately studied. MATERIALS AND METHODS: Adult rabbits were prepared by creation of skin donor site wound on the back, catheterization of the carotid artery and jugular vein, and placement of a nasogastric feeding tube under general anesthesia. The rabbits were given total enteral nutrition thereafter. On day 5 stable isotope tracers were infused to measure the kinetics of protein (reflecting tissue repair) and DNA (reflecting cell proliferation) in the wound. During the isotope tracer infusion, regular human insulin was infused at 2.5 mU/kg per min with concomitant glucose infusion for euglycemia in an insulin group but not in a control group. RESULTS: Plasma insulin concentration was 140±26 µU/mL in the insulin group (n=8), greater (P<0.001) than that of 16±3 µU/mL in the control group (N=8). In the insulin group the fractional synthetic rates of wound protein and DNA were 9.0±1.2 and 5.4±0.5%/day, greater (P < or=0.05) than those of 6.4±0.5 and 4.0±0.6%/day in the control group, respectively. Wound protein fractional breakdown rates were not significantly (P =0.2) different; net protein deposition rate was ~50% greater in the insulin than in the control group, although the difference was not statistically different (P=0.2). CONCLUSIONS: Insulin infusion increased wound protein and DNA synthesis, which are anticipated to promote tissue repair and reepithelialization.

Acute propranolol infusion stimulates protein synthesis in rabbit skin wound.

BACKGROUND: Propranolol administration has been demonstrated to improve cardiac work, decrease energy expenditure, and attenuate lipolysis in burned patients; however, its effect on wound healing has not been reported. METHODS: In rabbits, a partial-thickness skin donor site wound was created on the back, and catheters were placed in the carotid artery and jugular vein. A nasogastric feeding tube was placed for enteral feeding. On day 5 after injury, stable isotope tracers were infused to determine protein and DNA kinetics in the wound. Propranolol hydrochloride was injected in 1 group during the tracer infusion to decrease heart rate, and the other group without propranolol injection served as a control. RESULTS: The propranolol infusion decreased heart rate by 21%. The protein fractional synthetic rate in the wound was greater in the propranolol group (8.6 +/- 0.9 vs 6.1 +/- 0.5%/day, P < .05). Wound protein fractional breakdown rates were not significantly different. The rate of protein deposition (synthesis - breakdown) was increased in the propranolol group (5.0 +/- 1.2 vs 2.8 +/- 0.7%/day, P = .07). Wound DNA fractional synthetic rates were comparable. The protein fractional synthetic rate was correlated with percent decrease in heart rate, but expression of the beta-adrenergic receptors and downstream signaling cascades in local wounds were not affected after propranolol treatment. CONCLUSION: Propranolol infusion increased wound protein synthetic rate and tended to increase wound protein deposition rate, which might be beneficial to wound healing. These changes might reflect a systemic response to the beta-adrenergic blockade.

Inhibition of vascular endothelial growth factor expression in keloid fibroblasts by vector-mediated vascular endothelial growth factor shRNA: a therapeutic potential strategy for keloid.

Vascular endothelial growth factor (VEGF) plays important roles in the regulation of angiogenesis and inflammation in both pathological and physiological wound repair. Several strategies have been developed for keloid therapy; however, a universally effective treatment has not been explored to date. In this study, three potential short interfering RNA (siRNA) sequences for the VEGF gene were cloned into expression plasmids and transfected into keloid fibroblasts. PGC-VEGF shRNA 2 (short hairpin RNA 2) plasmid significantly inhibited VEGF expression determined by real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and fibroblasts growth was also significantly by (methyl thiazolyl tetrazolium) MTT assay and apoptosis detection, whereas the control transfection showed no obviously effects. Plasminogen activator inhibitor-1 (PAI-1) expression in pGC-VEGF shRNA2 group was also obviously downregulated when compared to the pGC-VEGF shRNA negative control and mock group. These results suggest that modulation of VEGF production by vector-based RNAi in keloid fibroblasts may be a therapeutic potential strategy for keloid.

Proliferation hemangiomas formation through dual mechanism of vascular endothelial growth factor mediated endothelial progenitor cells proliferation and mobilization through matrix metalloproteinases 9.

Infantile hemangioma is the most common tumor of infancy and the mechanism leading to proliferation hemangiomas formation is poorly understood and currently no successful treatment modality exists. We hypothesize that EPCs formed during proliferation hemangiomas, as the result of vascular endothelial growth factor (VEGF) stimulation through MMP9, play the major role in the control of cell proliferation and capillary-like vessels production. Accepting the hypothesis to be correct, a therapy that inhibits EPC mobilization and proliferation can be used to prevent the proliferation hemangiomas formation. Current therapies are only partially effective and safe because they could not eliminate all the relative factors of proliferation hemangiomas formation at all, such as: EPCs in the peripheral blood, and at the same time inducing death (apoptosis and necrosis) of other normal cells. A more efficient prevention of proliferation hemangiomas could be achieved using specific drugs or biologic methods that inhibit EPC mobilization and proliferation. Therapy based on gene therapy, capable to specifically inhibit VEGF and MMP9 expression in gene level, can be possibly effective.

[An investigation of bacterial ecology and analysis of bacterial resistance to antibiotics in a burn ward in Nanning district].

OBJECTIVE: To investigate the changes in the bacterial ecology and to analyze the bacterial resistance to antibiotics in a burn ward in Nanning district during the past 15 years, so as to provide reference to the clinical management of burn infection under subtropical climate. METHODS: Five thousand eight hundred and fifty-five strains of bacteria were isolated from the wounds and blood of 2269 burn patients admitted to our hospital from April of 1989 to March of 2004. Kiry-Bauer method was employed for the detection of antibiotic sensitivity test. The bacterial examination and bacterial resistance were analyzed in spans of every five years. RESULTS: Burn patients in our district were mainly infected by the gram negative bacilli (3559 strains, accounting for 60.79%), among which Pseudomonas aeruginosa, Enterobacter cloacae and Nitrate negative bacilli were major ones in every period. Gram positive cocci accounted for 33.99% (1990 strains), which ranked the second, among which Staphylococcus aureus, Staphylococcus epidermidis, and Coagulase negative staphylococci (MRCNS) were the most predominant ones. The bacterial resistance to multiple antibiotics, such as Gentamicin, third generation of Cephalosporin, and Norfloxacin showed a tendency of increase or maintained at high level while the incidence of resistance to Imipenem and Vancomycin was very low. CONCLUSION: The climate and the way of using antibiotics exerted direct effects on the status of the bacterial ecology and change in bacterial resistance to various antibiotics.