Role of c-Jun NH (2)-terminal kinase in insulin resistance after burn / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the role of c-Jun NH (2)-terminal kinase (JNk) in insulin resistance after burn and its mechanism.</p><p><b>METHODS</b>Twenty-four Sprague-Dawley rats were randomized to control, burn and burn + anisomycin groups. The rats in control group received sham burn trauma, and burn and burn + anisomycin groups received 30% total body surface area (TBSA) full thickness burn injury. Anisomycin (5 mg/kg) together with 250 microl dimethyl sulfoxide (DMSO) was injected to the rats in anisomycin group intravenously, and only 250 microl DMSO in the other two groups. Euglycemic-hyperinsulinemic glucose clamps was performed 2 hours after the injection. The changes of phospho-serine 307, phospho-tyrosine of insulin receptor substrate (IRS)-1 and phospho-JNK in muscle tissues were determined and compared using immunoprecipitation and Western blot analysis or immunohistochemistry in the three groups.</p><p><b>RESULTS</b>The infusing rates of total 10% glucose (mg x kg(-1) x min(-1)) in control, burn and burn + anisomycin group were 12.3 +/- 0.4, 6.6 +/- 0.3, 6.5 +/- 0.4, respectively. The level of IRS-1 Serine 307 phosphorylation and phospho-JNK in muscle increased significantly, while insulin-induced tyrosine phosphorylation of IRS-1 decreased markedly after burn.</p><p><b>CONCLUSIONS</b>The activation of JNK elevates the level of IRS-1 phospho-serine 307 and might play a role in insulin resistance after burn in rats.</p>

Amelioration of insulin resistance after scald by c-Jun N-terminal kinase inhibitor in rat / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the role and mechanism of c-Jun N-terminal kinase (JNk) inhibitor (SP600125) in amelioration of insulin resistance after scald.</p><p><b>METHODS</b>Twenty-four Sprague-Dawley rats were randomized into sham (the process of scald was mimicked by water at room temperature) , scald, scald and SP600125 groups. The rats were inflicted with 30% TBSA full-thickness scald in the latter two groups. Euglycemic-hyperinsulinemic glucose clamp experiment was carried out 4 days after scald. SP600125 was administered to the rats in scald and SP600125 2 hrs before Euglycemic-hyperinsulinemic glucose clamp was performed. Changes in the phospho-Serine307 and phospho-tyrosine of IRS-1 activity, as well as expression of phospho-JNK in muscles were determined.</p><p><b>RESULTS</b>Euglycemic-Hyperinsulinemic Glucose Clamps experiment showed that the infusion rate of 100 g/L glucose in sham, scald, scald and SP600125 groups were (12. 33 +/-0. 42) , (6. 61 +/-0. 27) , (11. 11 +/-0. 68) mgx kg(-1) x min(-1) , respectively ( P <0.01). The level of IRS-1 Serine307 phosphorylation and JNK activity in muscles were significantly increased, while insulin-induced tyrosine phosphorylation of IRS-1 decreased markedly after scald. Compared with scald group, the level of IRS-1 Serine307 phosphorylation and JNK activity in scald and SP600125 group were decreased but tyrosine phosphorylation was elevated.</p><p><b>CONCLUSION</b>SP600125 can partially ameliorate insulin resistance after scald by inhibition of JNK activation, and decrease the level of IRS-1 phospho-serine307.</p>

Experimental study of human skin fibroblasts cultured in three-dimension(3D) / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the biological characters of human skin fibroblasts in fibroblast populated collagen lattice (FPCL).</p><p><b>METHODS</b>The human fibroblasts were cultured in 3D and the collagen of the rat tail was also prepared. They were examined with the comprising cell cycle and apoptosis, mRNA expression of TGF beta1, and fibronectin, and cell morphology.</p><p><b>RESULTS</b>The flow cytometry showed that the G0/G1, stage cells were 79% +/- 3%, 87% +/- 2% after the 7 days and 14 days separately, and there were not apoptosis peak observed. RT-PCR analysis revealed that the mRNA expression of TGF beta1, and fibronectin had no difference between human skin fibroblasts cultured in 3D and 2D. Electron microscope showed the cells were plenty of chromatin and organelles.</p><p><b>CONCLUSIONS</b>The proliferation of the human skin fibroblasts in FPCL is slow, but its biological viability is better.</p>

Clinical observation of the long-term effects of rhEGF on deep partial-thickness burn wounds / 中华烧伤杂志

<p><b>OBJECTIVE</b>To evaluate the safety and long-term effect of recombinant human epithelial growth factor (rhEGF) on deep partial-thickness burn wounds.</p><p><b>METHODS</b>Thirty-seven burn patients were enrolled in this study and were observed by randomized, double-blinded and placebo-controlled protocol. An area of deep partial-thickness burn wounds from each patient was divided into control (C) and treatment (T) portions. The wound in C was treated with normal saline while that in T with rhEGF. The patients were followed-up for 1 and 4 years after wound healing. The healed wounds were evaluated by modified Vancouver scar scale in terms of scar index (SI).</p><p><b>RESULTS</b>1 year after wound healing, it was found that the SI in T group (7.19 +/- 1.67) was obviously lower than that in C group (8.92 +/- 1.78, P < 0.01). The SI in T group (6.12 +/- 1.54) was still evidently lower than that in C group (8.09 +/- 1.81, P < 0.01) four years after wound healing. There were no signs of development of tumor or cancer in all the tested burn wound areas.</p><p><b>CONCLUSION</b>External application of rhEGF might be beneficial to the healing quality of deep partial-thickness burn wound with less scar formation and better long-term effects, and it is safe.</p>