OBJECTIVETo observe the change in expression of vascular endothelial growth factor (VEGF) in serum and wound tissue of rats with electrical burn (EB), and to explore its regulation mechanism in the pathological changes of EB.

METHODSSixty-four SD rats were divided into normal control group (n = 8) and EB group (n = 56) according to the random number table. Eight rats in EB group were sacrificed at post injury hour (PIH) 6 and on post injury day (PID) 1, 3, 7, 14, 21, and 28, to collect wound muscle tissue and serum samples. Histopathological changes in wound tissue were observed with HE staining. The serum content of VEGF was determined with double-antibody sandwich enzyme-linked immunosorbent assay. The expression level of VEGF in wound tissue was determined with Western blotting. VEGF expression intensity in wound tissue was observed with immunohistochemical staining. The microvessel density (MVD) was calculated. The correlation between VEGF expression intensity and MVD was analyzed. Muscle tissue of calf and serum of the rats in normal control group without any treatment were collected for above-mentioned observations and determinations. Data were processed with one-way analysis of variance and Spearman hierarchy correlation analysis, and LSD-t test was applied for paired comparison.

RESULTS(1) In EB group, breakage of muscle fiber, heavy infiltration of inflammatory cells, and obvious tissue edema were observed at PIH 6 and on PID 1; new vessels were observed on PID 3; amount of granulation tissue and number of new vessels were found to be increased on PID 7. (2) In EB group, the serum level of VEGF was (43 ± 11) pg/mL at PIH 6, (44 ± 11) pg/mL on PID 1, and (74 ± 27) pg/mL on PID 14, which were all significantly higher than that in normal control group [(15 ± 9) pg/mL, with t values from 4.001 to 5.724, P values all below 0.01]. (3) The protein expression level of VEGF of wound tissue in EB group was higher than that in normal control group (0.21 ± 0.09) at each time point. The protein expression level of VEGF in EB group peaked on PID 7 (0.63 ± 0.13, t = 4.965, P < 0.05). (4) In EB group, strongly positive expression of VEGF was observed in inflammatory cells at early stage and in new vascular endothelial cells at late stage. (5) The expression intensity of VEGF was positively correlated with MVD in wound tissue on PID 3, 7, 14, 21, and 28 in EB group (r(s) = 0.834, P < 0.01).

CONCLUSIONSDifferent expression levels of VEGF were observed in serum and wound tissue of rats at various stages after EB, and they were closely correlated with different stages of fluid exudation and wound healing process after EB.

Animals ; Burns, Electric ; blood ; metabolism ; Female ; Granulation Tissue ; Male ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; blood ; metabolism ; Wound Healing

AIM:To investigate the effect of ozone bath on the pathological changes and the expression of cyto-kines,platelet-derived growth factor (PDGF), transforming growth factor-β3(TGF-β3), and tumor necrosis factor-α (TNF-α),in the wounds of deep second-degree burns in rats. METHODS:Male clean-grade SD rats(n=80) were ran-domly divided into 2 groups, ozone bath group and routine dressing group (control group), with 40 rats in each group. Deep second-degree burn wound was established on the back of the rats,and then the examinations were conducted at 3 d, 7 d,14 d and 21 d after burn. For the routine dressing group,the wound was cleaned by normal saline and covered with io-dophor vaseline gauze every 2 d. For the ozone bath group,before the dressing,the rats were put into the clean foam box to accept ozone fumigation for 20 min(50 mg/L),and then accepted dressing change as the same as that in control group every 2 d. At each time point,the tissue specimens from these rat wounds(at wound center) were taken. The rats in ozone bath group received cleaning by saline cotton and then the ozone bath fumigation, while the rats in control group only re-ceived cleaning by saline. After that,the tissue specimens were taken again for HE staining,immunohistochemical staining and semiquantitative observation combined with image data analysis. The concentrations of the cytokines PDGF, TGF-β3 and TNF-α in the wound were measured by double-antibody sandwich ELISA. RESULTS:In ozone bath group, the wounds were smooth with clear edge and slight inflammatory reaction,swelling and exudation were weaker,and the wound healing rate was higher than that in control group with significant difference. Under microscopic observation with HE stai-ning,slighter inflammatory reaction in ozone bath group was observed than that in control group at each time point,and the numbers of fresh capillaries,fibroblasts and epithelial cells were significantly larger than those in control group. The ex-pression levels of PDGF and TGF-β3in the wound tissue homogenate in ozone bath group were higher,and the expression level of TNF-α was significantly lower than those in control group at each time point with significant difference. CONCLU-SION:The ozone bath therapy improves the local pathological changes and promotes the expression of cytokines PDGF and TGF-β3,which are associated with wound healing,as well as reduces the expression of inflammatory mediator TNF-α in the rats with deep second-degree burns,thus promoting the wound healing and anti-inflammatory responses.

Insulin-like growth factor binding-protein-7 (IGFBP7) was obtained from our previous colonic adenocarcinoma (CRC) and normal mucosa suppression subtraction hybridization (SSH) cDNA libraries. By RT-PCR and immunohistochemistry, we found that IGFBP7 was overexpressed in CRC tissue compared to normal tissue. However, our in vitro experiments performed in 10 CRC cell lines showed that IGFBP7 expressed only in SW480 and Caco2 cell lines, which implied an underlying reversible regulatory mechanism. Using methylation-specific PCR (MSP) and bisulfite sodium PCR (BSP), we found that its expression was associated with DNA hypomethylation of exon1. This was further supported by the in vitro study which showed restored IGFBP7 expression after demethylation agent 5-aza-2'-deoxycytidine treatment. Correlation analysis between IGFBP7 expression and prognosis indicated that overexpression of IGFBP7 in CRC tissue correlated with favourable survival. Investigation of the functional role of IGFBP7 through transfection studies showed that IGFBP7 protein could inhibit growth rate, decrease colony formation activity, and induce apoptosis in RKO and SW620 cells, suggesting it a potential tumor suppressor protein in colorectal carcinogenesis. In conclusion, our study clearly demonstrated that IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis and its expression is associated with DNA hypomethylation of exon 1.
Adenocarcinoma ; genetics ; metabolism ; Apoptosis ; genetics ; Cell Line, Tumor ; Colorectal Neoplasms ; genetics ; metabolism ; DNA Methylation ; Exons ; Gene Expression Regulation, Neoplastic ; genetics ; Humans ; Insulin-Like Growth Factor Binding Proteins ; genetics ; metabolism ; Transfection ; Tumor Suppressor Proteins ; genetics ; metabolism