ABSTRACT
<p><b>OBJECTIVE</b>To study the mechanism underlying the inhibitory effects of peroxisome proliferator-activated receptor γ (PPARγ) agonists on transforming growth factor β1 (TGF-β(1))-induced scarring of skin.</p><p><b>METHODS</b>Fibroblasts isolated from healthy adult skin were cultured in vitro and divided into blank control group (serum-free DMEM culture), TGF-β(1) group (with stimulation of 10 ng/mL TGF-β(1) for 48 hours), troglitazone group (with the same treatment as in TGF-β(1) group after stimulation of 10 µmol/L troglitazone for 2 hours), and 15-dioxygen prostaglandin J2 (15d-PGJ2) group (with the same treatment as in TGF-β(1) group after stimulation of 10 µmol/L 15d-PGJ2 for 2 hours) according to the stimulation added into DMEM. The expression of connective tissue growth factor (CTGF) was determined with Western blot. The mRNA levels of CTGF, matrix metalloproteinase-1 (MMP-1) and platelet-derived growth factor (PDGF) were determined with real-time fluorescence RT-PCR. Data were processed with one-way analysis of variance.</p><p><b>RESULTS</b>The expression of CTGF at mRNA and protein levels in skin fibroblasts were significantly increased in TGF-β(1) group as compared with control group; while expression of CTGF at mRNA and protein levels in 15d-PGJ2 and troglitazone groups were significantly decreased as compared with that in TGF-β(1) group. The mRNA level of MMP-1 in TGF-β(1) group (0.193 ± 0.051) was obviously lower than that in blank control group (1.281 ± 0.195, F = 12.811, P < 0.01), while the mRNA levels of MMP-1 in troglitazone group (0.417 ± 0.043) and 15d-PGJ2 group (0.485 ± 0.027) were significantly increased as compared with that in TGF-β(1) group (F = 12.811, P values all below 0.01). The mRNA level of PDGF in TGF-β(1) group (1.044 ± 0.237) was obviously higher than that in control group (0.349 ± 0.057, F = 16.848, P < 0.01), while the levels in troglitazone group (0.677 ± 0.055) and 15d-PGJ2 group (0.511 ± 0.017) were significantly decreased as compared with that in TGF-β(1) group (F = 16.848, P values all below 0.01).</p><p><b>CONCLUSIONS</b>The inhibitory effect of activated PPARγ on the expression of CTGF induced by TGF-β(1) may be the main mechanism of its inhibitory effect on TGF-β(1)-induced scarring on skin, and its influence on MMP-1 and PDGF may also be one of the underlying mechanisms.</p>
Subject(s)
Humans , Cell Line , Connective Tissue Growth Factor , Metabolism , Fibroblasts , Metabolism , Matrix Metalloproteinase 1 , Metabolism , PPAR gamma , Receptors, Platelet-Derived Growth Factor , Metabolism , Signal Transduction , Transforming Growth Factor beta1 , MetabolismABSTRACT
Objective To investigate the effects of escharectomy at different time points on myocardial damages in scalded rats during shock stage. Methods A total of 42 rats were inflicted with 30% TBSA Ⅲ scalding on their backs and then randomly and equally divided into 7 groups: burned control group (C) and escharectomy groups at hour 1, 3, 6, 12, 24 and 36 postburn. Another 6 rats were employed as normal control (N). The serum levels of creatine kinase isoenzymes MB (CKMB), aspartate aminotransferase (AST) were determined and morphological changes in myocardial tissues were observed 72 hours after the burn. Results The serum levels of CKMB and AST were higher in the C group than in other groups, and the levels in escharectomy groups were increased along with the prolongation of scar cutting. Pathologically, the myocardial tissues were severely damaged in C group, and the later the scars were cut, the severe the damages were in the escharectomy groups except the 2 groups with scars cut at hour 1 and 3. Conclusion Escharectomy in shock stage can effectively prevent the damage of the myocardial tissues from postburn injury and the earlier it is performed, the better the result is.
ABSTRACT
Objective To investigate the effects of escharectomy at different time points on myocardial damages in scalded rats during shock stage. Methods A total of 42 rats were inflicted with 30% TBSA Ⅲ scalding on their backs and then randomly and equally divided into 7 groups: burned control group (C) and escharectomy groups at hour 1, 3, 6, 12, 24 and 36 postburn. Another 6 rats were employed as normal control (N). The serum levels of creatine kinase isoenzymes MB (CKMB), aspartate aminotransferase (AST) were determined and morphological changes in myocardial tissues were observed 72 hours after the burn. Results The serum levels of CKMB and AST were higher in the C group than in other groups, and the levels in escharectomy groups were increased along with the prolongation of scar cutting. Pathologically, the myocardial tissues were severely damaged in C group, and the later the scars were cut, the severe the damages were in the escharectomy groups except the 2 groups with scars cut at hour 1 and 3. Conclusion Escharectomy in shock stage can effectively prevent the damage of the myocardial tissues from postburn injury and the earlier it is performed, the better the result is.