Effects of advanced glycosylation end products on the biological behavior of neutrophils / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effects of advanced glycation end products (AGE) on the biological behavior of neutrophils in vitro, to look for the relationship between accumulation of AGE and abnormal inflammation in wound healing in diabetic mellitus patients.</p><p><b>METHODS</b>Neutrophils were isolated from SD rats and incubated in vitro. The cells were divided into four groups according to different concentrations of AGE in cell suspension: control group (C, with treatment of RPMI - 1640), A group (with treatment of 0.315 mg/mL AGE + RPMI - 1640), B group (with treatment of 0.625 mg/mL AGE + RPMI - 1640), D group (with treatment of 1.250 mg/mL AGE + RPMI - 1640). Activity of neutrophils were determined by MTT colorimetric assay. Selectin-L mRNA expressions were analyzed by reversible transcription polymerase chain reaction (RT -PCR) technique. The levels of reactive oxygen species (ROS) in neutrophils were measured with DCFH-DA method. The protein concentration of neutrophil elastase (NE) was assayed by ELISA.</p><p><b>RESULTS</b>The activity of neutrophils were obviously increased in A, B, and D groups when compared with that in C group [(0.170 +/- 0.040) in C group, (0.320 +/- 0.030) in A group, (0.380 +/- 0.020) in B group, (0.290 +/- 0.010) in D group, P <0. 05]. The expression of Selectin-L mRNA in A, B, D groups were significantly higher than that in C group (0.95 +/- 0.08, 1.36 +/- 0.27, 0.50 +/- 0.26.vs.0.36 +/- 0.26, P < 0.05. respectively). The ROS levels in A, B, D groups was markedly higher than that in C group (1.64 +/- 0.20, 2.16 +/- 0.26, 3.26 +/- 0.75. vs. 0.72 +/- 0.15, P <0.05, respectively). The levels of NE in A, B, D groups were significantly increased when compared with that in C group(1.98 +/- 0.43, 2.50 +/- 0.43, 2.01 +/- 0.18 vs 0.91 +/- 0. 21, P <0.05, respectively).</p><p><b>CONCLUSION</b>AGE can enhance the activity of neutrophil, with change in cellular biological behaviors, which may be one of main reasons for abnormal inflammation in wounds of diabetes mellitus patients.</p>

Study of neovascularization disturbance in deep partial-thickness scald in rats with diabetes mellitus / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the relationship between the degree of neovascularization and non-healing wounds in scalded rats with diabetic mellitus.</p><p><b>METHODS</b>Sixty Sprague-Dawley rats were randomly divided into control group (C, n = 30, with treatment of isotonic saline) and streptozocin (STZ)-induced diabetic group (D, n = 30, with treatment of STZ), and then they were inflicted with 20% TBSA deep partial thickness scald. Wound specimens were harvested immediately after scald and on 1, 3, 7, 10, 14, 21 post scald days (PSD) to observe histological changes, and wound healing rates were calculated. Degree of neovascularization in wound (labeled with blue microsphere) and the quantity of vascular endothelial cells (labeled with red CD31) were also measured by double-labeling immunofluorescence.</p><p><b>RESULTS</b>Compared with those in C group, Wound healing rate and histological value scores were lowered, and the degree of neovascularization was abated markedly at each time point. The degree of neovascularization in D group (12.00 +/- 1.40) was obviously lower than that in C group on 7 PSD (60.00 +/- 3.00, P <0.01). There was no obvious difference in the number of vascular endothelial cells in both groups, however, the majority of endothelial cells had not formed functional capillaries in D group.</p><p><b>CONCLUSION</b>Vascular endothelial cell can proliferate actively with poor blood supply in diabetic nonhealing with deep partial-thickness scald wounds, but it is still poor in blood supply due to lack of functional capillaries.</p>

Study on the mechanism of scar formation: epidermis template defect theory / 中华烧伤杂志

Dermal defection and the degree of its loss determine the natural process of wound healing, which is the key reason leading to excess scar hyperplasia. The function of tri-dimensional structure in dermis acts as a template to regulate the properties of reparative cells. The template structure induces the reparative cells to grow into the structure which changes the skin mechanic status on wound area. Also, the component of extracellular matrix can affect behaviours of fibroblasts negatively or positively, for the reason that the structure of dermal tissue has a permissive effect on the dermal components in regulating behaviours of reparative cells. Therefore, the behaviors of cells depend on the structure of the template. The suitable tri-dimensional structure of dermis facilitates normal cell cycling. The more the structure of dermis closed to its physiological status, the better the biological behaviors of cells act. Moreover, the integrity as well as the continuity of dermal tissue is the prerequisite for serving as a template. The damage to the integrity and the continuity of dermal tissue may be one of the key reasons to lead abnormal tissue repair and scar formation. Thus, we hypothesize that the loss of dermal template may be one of the mechanism of abnormal scar formation and propose the theory of extracellular matrix framework deficiency or destruction.

Effects of advanced glycation end-products on skin keratinocytes by NF-?B activation / 中华创伤杂志

Objective To investigate the effects of advanced glycation end-products(AGEPs)on the function of normal keratinocytes in vitro so as to explore the role of AGEPs in impaired wound healing. Methods Normal rat keratinocytes were incubated with different concentrations of AGEPs.After 48 hours of culturing,the cell proliferation rates were measured by MTT colorimetric determination.The cell cycle distributions and apoptosis were analyzed with flow cytometry,and the migration was investigated by 24-well fluorimetric cell migration assay kit by exposing to 100?g/ml AGEPs.Nuclear extracts from these cells were examined for binding of nucleotides containing NF-?B consensus by immunocytochemistry and EMSA in vitro.Results The proliferations of normal keratinocytes were significantly arrested and many cells were induced to early apoptosis compared with control ones(P＜0.05)by exposing to AGEPs for 48 hours. Meanwhile AGEPs also irritated keratinocytes migration compared with control ones(P＜0.05).Inhibiting the activation of NF-?B could partly recover the proliferation of keratinocytes,reverse apoptosis and attenu- ate migration.Conclusion AGEPs are correlated with the migration,proliferation and apoptosis of kera- tinocytes by NF-?B.