OBJECTIVE: To explore the relationship between the expression change of cytokines and the wound age during the healing process of rats skin wound. METHODS: Immunohistochemical and image-analysis methods were performed on vital skin wounds(after incision 0.5-168 h am) and postmortem damage(after incision 0.5-6 h pm). RESULTS: The expression of the cytokines PDGF-beta, PDGFR-beta, TGF-beta 1, and bFGF in the epithelial cells was already enhanced since 0.5 h am after damage and their strongest expression reaction was seen at 24-96 h am. In addition, the expression of PDGF-beta, PDGFR-beta, TGF-beta 1 and bFGF was also found in the macrophages and the fibroblasts of the granulation tissue, and the expression changes in the postmortem damage group showed that the skin tissue within 0.5-3 h after incision showed immunohistochemical changes but weakly expression and 3 h thereafter no any change was found. CONCLUSION The expression characteristics of the above mentioned cytokines in wound repair should be related to the wound age and it reminds therefore that they may be used as immunohistochemical criteria for accurate determining the wound age.
Animals ; Cytokines/biosynthesis* ; Female ; Fibroblast Growth Factor 2/biosynthesis* ; Male ; Platelet-Derived Growth Factor/biosynthesis* ; Rats ; Rats, Wistar ; Receptor, Platelet-Derived Growth Factor beta/biosynthesis* ; Skin/metabolism* ; Time Factors ; Transforming Growth Factor beta/biosynthesis* ; Transforming Growth Factor beta1 ; Wound Healing

OBJECTIVETo study the expression and significance of platelet derived growth factor (PDGF) and its receptor (PDGFR) in liver tissues of patients with chronic hepatitis fibrosis and liver cirrhosis.

METHODSThe expression, distribution, quantitation, and correlation of PDGF-A, PDGF-B, PDGFR-alpha, PDGFR-beta, and alpha-SMA in the liver tissues were analyzed by immunohistochemical techniques in 21 patients with chronic hepatitis and 42 patients with liver cirrhosis.

RESULTSIn the liver tissues of chronic hepatitis and liver cirrhosis, PDGF and its receptor and alpha-SMA mainly distributed in the fibrotic septa and the infiltration area of inflammation, particularly in branch spindle-shaped cells (activated HSC). The expression of PDGF-B and PDGFR-beta was stronger than that of PDGF-A and PDGFR-alpha with a significant difference between them (P<0.05 approximately 0.01). The expression and distribution of alpha-SMA was basically identical with the expression and distribution of PDGF-A, PDGF-B and PDGFR-alpha, PDGFR-beta and quantitative analysis showed a positive correlation (r=0.606, P<0.001).

CONCLUSIONSPDGF and PDGFR play a key role in liver fibrogenesis and development. The biologic effects of PDGF are elicited through activising HSC. Inhibiting PDGF and its receptor is a new approach to the treatment of liver fibrosis.

Actins ; biosynthesis ; physiology ; Adolescent ; Adult ; Aged ; Female ; Hepatocytes ; metabolism ; Humans ; Liver Cirrhosis ; metabolism ; Male ; Middle Aged ; Muscle, Smooth ; chemistry ; Platelet-Derived Growth Factor ; biosynthesis ; physiology ; Proto-Oncogene Proteins c-sis ; biosynthesis ; physiology ; Receptor, Platelet-Derived Growth Factor alpha ; biosynthesis ; physiology ; Receptor, Platelet-Derived Growth Factor beta ; biosynthesis ; physiology

OBJECTIVETo investigate the expression of PDGF receptor-beta and its correlation with extracellular matrix in hepatic tissue during hepatic fibrosis.

METHODSThe model of hepatic fibrosis in rats was induced by carbon tetrachloride. PDGF receptor-beta subunit, collagen I, collagen III and a-SMA in hepatic tissues of these rats were examined using immunohistochemistry. The correlation between PDGF receptor-beta subunit and collagen I, III was analyzed using SAS software after the results of immunohistochemistry were semi-quantified.

RESULTSPDGF receptor-beta subunit and a-SMA were not detected in normal controls. Collagen I and III were distributed in the portal tracts and beneath the endothelia of the central veins and of the Disse spaces. Two weeks after CCl4 injection, the PDGF receptor-beta and a-SMA were detected, and the expression of collagen I and III increased. At the end of 4 and 6 weeks, the above four proteins were further increased. Two weeks after CCl4 injection, PDGF receptor-beta had no apparent correlation with collagen I and III. However, PDGF receptor-beta had a significant correlation with collagen I and III 2 weeks later, and the correlation coefficient was 0.74 and 0.60 respectively at 4 weeks, and 0.83 and 0.67 respectively at 6 weeks. PDGF receptor-beta had a significant correlation with a-SMA during the whole process of hepatic fibrosis and the correlation coefficient was 0.62, 0.69 and 0.81, respectively at the time of 2, 4 and 6 weeks after CCl4 injection.

CONCLUSIONThe PDGF receptor-beta was overexpressed during the process of hepatic fibrosis development, and it significantly correlated with collagen I and collagen III.

Animals ; Carbon Tetrachloride ; Carbon Tetrachloride Poisoning ; Collagen Type I ; biosynthesis ; genetics ; Collagen Type III ; biosynthesis ; genetics ; Extracellular Matrix ; metabolism ; Liver ; metabolism ; Liver Cirrhosis, Experimental ; chemically induced ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, Platelet-Derived Growth Factor beta ; biosynthesis ; genetics

BACKGROUNDActivation and proliferation of hepatic stellate cells (HSC) is essentially involved in the development and progression of hepatic fibrosis. The most potent growth factor for HSC is platelet-derived growth factor receptor (PDGF) and PDGF receptor beta subunit (PDGFR-beta) is the predominant signal transduction pathway of PDGF which is overexpressed in activated HSC. This study investigated the cleavage activity of hammerhead ribozyme targeting PDGFR-beta mRNA in HSC and the effect on biological characteristics of HSC.

METHODSExpression vector of anti-PDGFR-beta ribozyme was constructed and transfected into rat activated HSC with lipofectamin. The positive cell clones were gained by G418 selection. The expression of PDGFR-beta, alpha-smooth muscle actin, and typeI and type III collagen were detected by using Northern blot, Western blot and immunocytochemical staining, respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was analyzed by using flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.

RESULTSThe expression of PDGFR-beta at mRNA and protein level was markedly reduced in ribozyme-transfected HSC by 49% - 57% (P < 0.05 - 0.01). The proliferation and alpha-smooth muscle actin expression of ribozyme-transfected HSC were significantly decreased (P < 0.05 - 0.01), and the type I and type III collagen synthesis were also reduced (P < 0.01). In addition, the proliferative response of ribozyme-transfected HSC to PDGF BB was significantly inhibited. Otherwise, the apoptotic cells were significantly increased in ribozyme-transfected HSC (P < 0.01), and typical apoptotic cells could be found under transmission electron microscopy.

CONCLUSIONSThe anti-PDGFR-beta ribozyme effectively cleaved the target RNA and significantly inhibited its expression, which blocked the signal transduction of PDGF at receptor level, inhibited HSC proliferation and collagen synthesis, and induced HSC apoptosis. These results suggest that inhibiting PDGFR-beta expression of HSC may be a new target for the therapy of liver fibrogenesis, and ribozyme may be a useful tool for inhibiting PDGFR-beta expression.

Actins ; biosynthesis ; Animals ; Apoptosis ; Cell Proliferation ; Cells, Cultured ; Collagen ; biosynthesis ; Liver ; cytology ; Liver Cirrhosis ; drug therapy ; pathology ; RNA, Catalytic ; pharmacology ; RNA, Messenger ; metabolism ; Rats ; Receptor, Platelet-Derived Growth Factor beta ; genetics

OBJECTIVETo study the cleavage activity of hammerhead ribozyme targeting at platelet-derived growth factor receptor beta subunit (PDGFR- beta) mRNA in hepatic stellate cells (HSCs) and its effect on the biological characters of HSCs.

METHODSExpression vector of anti-PDGFR- beta ribozyme was constructed and transfected into rat-derived HSC-T6 cells with lipofectin. The positive cell clones were gained by G418 selection. The expression of PDGFR- beta, alpha-smooth muscle actin (alpha-SMA), and type I and type III collagen was detected by means of northern blot, Western blot and immunocytochemical staining respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was demonstrated with flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.

RESULTSThe expression of PDGFR- beta at mRNA and protein level was markedly reduced in ribozyme-transfected HSCs only 43% to 51% of that in control cells (t > or = 3.957, P < 0.05), and alpha-SMA expression level, type I and type III collagen synthesis ability were also reduced (t > or = 6.790, P < 0.01). The proliferation of ribozyme-transfected HSCs was significantly decreased (t > or = 3.858, P < 0.05), and the proliferation response to PDGF BB was markedly inhibited. However the apoptotic rate was significantly increased in ribozyme-transfected HSCs (chi2 > or = 14.157, P < 0.01), and typical apoptotic cells could be found under transmission electron microscopy.

CONCLUSIONSThe anti-PDGFR- beta ribozyme can be expressed stably in HSCs, cleave the target RNA effectively, inhibit HSCs proliferation and collagen synthesis, and induce HSC apoptosis. The results suggest that inhibiting PDGFR- beta expression in HSCs may be a new therapy for liver fibrosis.

Apoptosis ; drug effects ; Cell Division ; Cells, Cultured ; Hepatocytes ; drug effects ; physiology ; Humans ; Liver ; pathology ; RNA, Catalytic ; pharmacology ; RNA, Messenger ; biosynthesis ; Receptor, Platelet-Derived Growth Factor beta ; antagonists & inhibitors ; metabolism