This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/β-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/β-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.
Rats ; Animals ; PPAR gamma/metabolism* ; Fagopyrum/genetics* ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; beta Catenin/metabolism* ; Interleukin-6 ; Flavonoids/pharmacology* ; Propranolol/pharmacology* ; Ventricular Fibrillation ; Dinoprostone ; Wnt Signaling Pathway ; Plant Leaves/metabolism* ; Flowers/metabolism* ; Apoptosis ; Cardiac Complexes, Premature

Renal tubulointerstitial fibrosis is the common ending of progressive renal disease. It is worth developing new ways to stop the progress of renal fibrosis. Peroxisome proliferator-activated receptor-γ (PPARγ) agonists have been studied to treat diabetic nephropathy, cisplatin-induced acute renal injury, ischemia reperfusion injury and adriamycin nephropathy. In this study, unilateral ureteral obstruction (UUO) was used to establish a different renal fibrosis model. PPAR? agonist pioglitazone was administrated by oral gavage and saline was used as control. At 7th and 14th day after the operation, mice were sacrificed for fibrosis test and T lymphocytes subsets test. Unexpectedly, through MASSON staining, immunohistochemistry for α-SMA, and Western blotting for a-SMA and PDGFR-β, we found that pioglitazone failed to attenuate renal fibrosis in UUO mice. However, flow cytometry showed that pioglitazone down-regulated Th1 cells, and up-regulated Th2 cells, Th17 cells and Treg cells. But the Th17/Treg ratio had no significant change by pioglitazone. Real-time PCR results showed that TGF-β and MCP-1 had no significant changes, at the same time, CD4(+) T cells associated cytokines were partially regulated by pioglitazone pretreatment. Taken together, pioglitazone failed to suppress renal fibrosis progression caused by UUO.
Animals ; Chemokine CCL2 ; metabolism ; Fibrosis ; Kidney ; pathology ; Kidney Diseases ; drug therapy ; etiology ; Male ; Mice ; Mice, Inbred C57BL ; PPAR gamma ; agonists ; T-Lymphocyte Subsets ; drug effects ; Thiazolidinediones ; administration & dosage ; pharmacology ; therapeutic use ; Transforming Growth Factor beta ; metabolism ; Urethral Obstruction ; complications

OBJECTIVETo explore the effect of curcumin on TGF-β2 regulated peroxisome proliferater activated receptor y (PPAR-γ)/platelet derived growth factor β (PDGF-β) signaling pathway in lung fibroblasts of mice.

METHODSC57BL/6 mouse lung fibroblasts were in vitro cultured with TGF-β2, curcumin, or TGF-β2 plus curcumin. The cell proliferation was detected by cell growth counting in the blank control group, low, middle, and high dose curcumin groups (5, 25, 50 μmol/L), the TGF-β2 (10 ng/mL) group, TGF-β2 (10 ng/mL) plus curcumin (5, 25, 50 μmol/L) groups. mRNA expressions of PPAR-γ, platelet-derived growth factor receptor β (PDGFR-β), fibroblast growth factor R1 (FGFR1) were detected using reverse transcription PCR. Protein levels of PPAR-γ and collagen-1 were detected using Western blot and ELISA in the blank control group, the TGF-β2 group, the TGF-β2 (10 ng/mL) plus curcumin 50 μmol/L group.

RESULTSCompared with the blank control group, curcumin 50 μmol/L showed the most significant inhibition on cell proliferation at 48 h and 72 h. Compared with the TGF-&beta;2 group, TGF-&beta;2 (10 ng/mL) plus curcumin 50 mol/L also showed the most significant inhibition on cell proliferation at 48 h and 72 h. Compared with the blank control group, mRNA expressions of PPAR-γ and PDGF-&beta;, as well as protein expression of PPAR-γ increased, the collagen-1 expression also increased in the TGF-&beta;2 group (P < 0.05). Compared with the TGF-&beta;2 group, mRNA expressions of PPAR-γ obviously increased in the TGF-&beta;2 (10 ng/mL) plus curcumin 25 μmol/L group and the TGF-&beta;2 (10 ng/mL) plus curcumin 50 μmol/L group, higher than that in the TGF-&beta;2 (10 ng/mL) plus curcumin 5 [μmol/L group (P < 0.05). mRNA expressions of PPAR-γ was higher in the TGF-&beta;2 (10 ng/mL) plus curcumin 50 μmol/L group than in the TGF-&beta;2 (10 ng/mL) plus curcumin 25 μmol/L group (P < 0.05). mRNA expressions of PDGF-&beta; was lower in TGF-&beta;2 (10 ng/mL) plus curcumin groups than in the TGF-&beta;2 group (P < 0.05). Besides, PDGF-&beta; mRNA expressions were lower in the TGF-&beta;2 (10 ng/mL) plus curcumin 50 μmol/L group than in the TGF-&beta;2 (10 ng/mL) plus curcumin 5 μmol/L group and the TGF-&beta;2 (10 ng/mL) plus curcumin 25 μmol/L group (P < 0.05). There was no statistical difference in FGFR1 mRNA expressions between the TGF-&beta;2 group and 3 TGF-&beta;2 plus curcumin groups (P > 0.05). Compared with the TGF-&beta;2 group, PPAR-γ protein expressions increased and collagen-1 protein expressions decreased in the TGF-&beta;2 (10 ng/mL) plus curcumin 50 μLmol/L group (P < 0.05, P < 0.01).

CONCLUSIONSCurcumin not only could inhibit TGF-&beta;2 induced proliferation of lung fibroblasts, but also could inhibit the synthesis of collagens. These might be associated with up-regulating PPAR-γ expressions and down-regulating PDGF-&beta; expressions. Therefore, curcumin might inhibit the occurrence and developing of lung fibrosis through blocking PPAR-γ/PDGF-&beta; signaling pathway.

Animals ; Cell Proliferation ; Collagen ; Curcumin ; pharmacology ; Fibroblasts ; metabolism ; Lung ; drug effects ; metabolism ; Mice ; Mice, Inbred C57BL ; PPAR gamma ; metabolism ; RNA, Messenger ; Receptor, Platelet-Derived Growth Factor beta ; metabolism ; Signal Transduction ; Transforming Growth Factor beta ; Transforming Growth Factor beta2 ; metabolism

OBJECTIVETo explore the effect of atorvastatin on cardiac hypertrophy and to determine the potential mechanism involved.

METHODSAn in vitro cardiomyocyte hypertrophy from neonatal rats was induced with angiotensin II (Ang II) stimulation. Before Ang II stimulation, the cultured rat cardiac myocytes were pretreated with atorvastatin at different concentrations (0.1, 1, and 10 μmol/L). The following parameters were evaluated: the myocyte surface area, 3H-leucine incorporation into myocytes, mRNA expressions of atrial natriuretic peptide, brain natriuretic peptide, matrix metalloproteinase 9, matrix metalloproteinase 2, and interleukin-1&beta;, mRNA and protein expressions of the δ/&beta; peroxisome proliferator-activated receptor (PPAR) subtypes.

RESULTSIt was shown that atorvastatin could ameliorate Ang II-induced neonatal cardiomyocyte hypertrophy in the area of cardiomyocytes, 3H-leucine incorporation, and the expression of atrial natriuretic peptide and brain natriuretic peptide markedly. Meanwhile, atorvastatin also inhibited the augmented mRNA level of several cytokines in hypertrophic myocytes. Furthermore, the down-regulated expression of PPAR- δ/&beta; at both the mRNA and protein levels in hypertrophic myocytes could be significantly reversed by atorvastatin treatment.

CONCLUSIONSAtorvastatin could improve Ang II-induced cardiac hypertrophy and inhibit the expression of cytokines. Such effect might be partly achieved through activation of the PPAR-δ/&beta; pathway.

Angiotensin II ; pharmacology ; Animals ; Atorvastatin Calcium ; pharmacology ; therapeutic use ; Cardiomegaly ; metabolism ; pathology ; prevention & control ; Cells, Cultured ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; PPAR delta ; genetics ; PPAR-beta ; genetics ; Rats ; Rats, Wistar

Curcumin is a principal polyphenolic curcuminoid extracted from turmeric rhizome, which has been used for treating inflammation of joints, ulcers, jaundice and other disorders in Asian traditional medicine. In recent years, many studies have indicated that curcumin plays important roles in treatment of liver diseases. Curcumin attenuates liver injury and non-alcoholic fatty liver disease by lowering the release of inflammation cytokines, minimizing oxidative stress, enhancing the sensitivity of insulin and altering lipid metabolism. Curcumin shows potent anti-fibrosis activity, contributing to inhibit the activation of hepatic stellate cells and reduce the deposition of extracellular matrix by its regulation of PPAR-γ, NF-ΚB and TGF-&beta; signaling pathways. Moreover, curcumin exhibits anti-cancer effect by inducing G2/M phase cell cycle arrest and apoptosis in several hepatoma cell lines. However, poor water solubility and low bioavailability of curcumin limit its clinical applications. To overcome its limited systemic bioavailability, many new approaches have been explored to deliver curcumin effectively. This article focuses on advances in the effects of curcumin and its derivatives for treatment of liver injury, non-alcoholic fatty liver disease, liver fibrosis and hepatocarcinoma.
Apoptosis ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Curcumin ; pharmacology ; Hepatic Stellate Cells ; drug effects ; Humans ; Inflammation ; drug therapy ; Liver Diseases ; drug therapy ; NF-kappa B ; metabolism ; Oxidative Stress ; drug effects ; PPAR gamma ; metabolism ; Signal Transduction ; Transforming Growth Factor beta ; metabolism

BACKGROUNDAcute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are the first steps in the development of multiple organ failure induced by sepsis. A systemic excessive inflammatory reaction is currently the accepted mechanism of the pathogenesis of sepsis. Several studies have suggested a protective role of the peroxisome proliferator activated receptor-&beta;/δ (PPAR-&beta;/δ) in related inflammatory diseases. But the role of PPAR&beta;/δ in ALI remains uncertain. The aim of this study was to investigate the role and possible mechanism of PPAR&beta;/δ in ALI induced by sepsis.

METHODSCecal ligation and puncture (CLP) was used as a sepsis model. Rats were randomly divided into four groups, the control group (CON, n = 6), sham-operation group (SHAM, n = 12), cecal ligation and puncture group (CLP, n = 30), GW501516 group (CLP+GW, n = 25), which underwent CLP and were subcutaneously injected with the PPAR-&beta;/δ agonist GW501516 (0.05 mg/100 g body weight). Survival was monitored to 24 hours after operation. Blood pressure, serum creatinine, blood urea nitrogen, aspartate aminotrasferase and alanine aminotrasferase were measured after CLP. Concentrations of tumor necrosis factor α (TNF-α) and interleukin (IL)-1&beta; in serum were detected by enzyme linked immunosorbent assay (ELISA) kits. Lung tissue samples were stained with H&E and scored according to the degree of inflammation. Bacterial colonies were counted in the peritoneal fluid. Alveolar macrophages were cultured and incubated with GW501516 (0.15 µmol/L) and PPAR&beta;/δ adenovirus and then treated with Lipopolysaccharide (2 µg/ml) for 2 hours. The TNF-α, IL-1&beta; and IL-6 RNA in lung and alveolar macrophages were determined by real-time PCR. Phosphorylation of signal transducer and activator of transcription 3 (STAT3) in lung and alveolar macrophages was detected by Western blotting.

RESULTSGW501516 significantly increased the survival of septic rats, decreased histological damage of the lungs, reduced inflammatory cytokines in serum and lung tissues of septic rats and did not increase counts of peritoneal bacteria. In vitro, GW501516 and over-expression of PPAR&beta;/δ attenuated gene expression of TNF-α, IL-1&beta; and IL-6 in alveolar macrophages. Both in vivo and in vitro, PPAR&beta;/δ inhibited the phosphorylation of STAT3.

CONCLUSIONPPAR&beta;/δ plays a protective role in sepsis induced ALI via suppressing excessive inflammation.

Acute Lung Injury ; drug therapy ; etiology ; Animals ; Cells, Cultured ; Male ; PPAR delta ; agonists ; metabolism ; PPAR-beta ; agonists ; metabolism ; Rats ; Rats, Sprague-Dawley ; Sepsis ; complications ; drug therapy ; Thiazoles ; therapeutic use

PURPOSE: We investigated the mRNA levels of peroxisome proliferator-activated receptor (PPAR)-alpha, PPAR-gamma, adipokines, and cytokines in the lung tissue of lean and obese mice with and without ovalbumin (OVA) challenge, and the effect of rosiglitazone, a PPAR-gamma agonist. METHODS: We developed 6 mice models: OVA-challenged lean mice with and without rosiglitazone; obese mice with and without rosiglitazone; and OVA-challenged obese mice with and without rosiglitazone. We performed real-time polymerase chain reaction for leptin, leptin receptor, adiponectin, vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, PPAR-alpha and PPAR-gamma from the lung tissue and determined the cell counts and cytokine levels in the bronchoalveolar lavage fluid. RESULTS: Mice with OVA challenge showed airway hyperresponsiveness. The lung mRNA levels of PPARalpha and PPAR-gamma increased significantly in obese mice with OVA challenge compared to that in other types of mice and decreased after rosiglitazone administeration. Leptin and leptin receptor expression increased in obese mice with and without OVA challenge and decreased following rosiglitazone treatment. Adiponectin mRNA level increased in lean mice with OVA challenge. Lung VEGF, TNF-alpha, and TGF-beta mRNA levels increased in obese mice with and without OVA challenge compared to that in the control mice. However, rosiglitazone reduced only TGF-beta expression in obese mice, and even augmented VEGF expression in all types of mice. Rosiglitazone treatment did not reduce airway responsiveness, but increased neutrophils and macrophages in the bronchoalveolar lavage fluid. CONCLUSION: PPAR-alpha and PPAR-gamma expressions were upregulated in the lung tissue of OVA-challenged obese mice however, rosiglitazone treatment did not downregulate airway inflammation in these mice.
Adipokines ; Adiponectin ; Animals ; Bronchoalveolar Lavage ; Cell Count ; Cytokines ; Inflammation ; Leptin ; Lung ; Macrophages ; Mice ; Mice, Obese ; Neutrophils ; Obesity ; Ovalbumin ; Ovum ; Peroxisome Proliferator-Activated Receptors ; Peroxisomes ; PPAR alpha ; Real-Time Polymerase Chain Reaction ; Receptors, Leptin ; RNA, Messenger ; Thiazolidinediones ; Transforming Growth Factor beta ; Transforming Growth Factors ; Tumor Necrosis Factor-alpha ; Vascular Endothelial Growth Factor A

BACKGROUNDS/AIMS: During the acute phase response, cytokines induce marked alterations in lipid metabolism including an increase in serum triglyceride levels and a decrease in hepatic fatty acid oxidation, in bile acid synthesis, and in high-density lipoprotein levels. METHODS: Peroxisome proliferator-activated receptors (PPARs: PPARalpha, beta/delta, and gamma) regulate fatty acid metabolism, glucose homeostasis, cell proliferation, differentiation and inflammation. Proinflammatory profiles including tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) are the important pathological factors in inflammatory responses during the pathological progression of the acute phase response. Lipopolysaccarides (LPS) induced the expression of TNF-alpha, IL-1beta, and IL-6. LPS-induced inflammation decrease the expression of peroxisome proliferator-activated receptor alpha (PPARalpha), PPARbeta/delta, PPARgamma, and coactivators PPARgamma co-activator 1 alpha (PGC-1alpha), PGC-1beta messenger RNA (mRNA) in the liver of Balb/c mouse. In addition, LPS-induced inflammation diminishes the protein level of PPARalpha, PPARbeta/delta, and PPARgamma. Proinflammatory cytokines including TNFalpha, IL-1beta, and IL-6 are the principal reducer of PPARs. However, the knockout mouse model against TNFalpha and IL-6 does not block decrease of PPARs in serum and liver. The mice were pretreated with fenofibrate at 100 mg/kg for 2 days. RESULTS: These treatment protocols increased the amount of PPARs mRNA in the liver. Fenofibrate inhibited LPS-induced TNF-alpha, IL-1beta, and IL-6 production in the serum and liver. Similar results were obtained when human hepatoma HepG2 cells exposed to LPS were co-incubated with fenofibrate. LPS-treated HepG2 cells decreased expression of IkappaB. Moreover, activation of PPARs abrogated LPS-induced degradation of IkappaB, thus suppressing LPS-induced NF-kappaB activities. CONCLUSIONS: Therefore, fenofibrate decreases the expression and secretion of TNF-alpha, IL-1beta, and IL-6 via the NF-kappaB signaling pathway, thus serving as therapeutic targets to attenuate inflammation that is involved in hepatic pathological progression.
Animals ; Bile ; Carcinoma, Hepatocellular ; Cell Proliferation ; Clinical Protocols ; Cytokines ; Fenofibrate ; Glucose ; Hep G2 Cells ; Homeostasis ; Humans ; Inflammation ; Interleukin-1beta ; Interleukin-6 ; Lipid Metabolism ; Lipoproteins ; Liver ; Mice ; Mice, Knockout ; NF-kappa B ; Peroxisome Proliferator-Activated Receptors ; Peroxisomes ; PPAR alpha ; PPAR-beta ; PPAR delta ; PPAR gamma ; RNA, Messenger ; Tumor Necrosis Factor-alpha

BACKGROUND: Insulin resistance is an integral feature of metabolic syndromes, including obesity, hyperglycemia, and hyperlipidemia. In this study, we evaluated whether the aloe component could reduce obesity-induced inflammation and the occurrence of metabolic disorders such as blood glucose and insulin resistance. METHODS: Male C57BL/6 obese mice fed a high-fat diet for 54 days received a supplement of aloe formula (PAG, ALS, Aloe QDM, and Aloe QDM complex) or pioglitazone (PGZ) and were compared with unsupplemented controls (high-fat diet; HFD) or mice fed a regular diet (RD). RT-PCR and western blot analysis were used to quantify the expression of obesity-induced inflammation. RESULTS: Aloe QDM lowered fasting blood glucose and plasma insulin compared with HFD. Obesity-induced inflammatory cytokine (IL-1beta, -6, -12, TNF-alpha) and chemokine (CX3CL1, CCL5) mRNA and protein were decreased markedly, as was macrophage infiltration and hepatic triglycerides by Aloe QDM. At the same time, Aloe QDM decreased the mRNA and protein of PPARgamma/LXRalpha and 11beta-HSD1 both in the liver and WAT. CONCLUSION: Dietary aloe formula reduces obesity-induced glucose tolerance not only by suppressing inflammatory responses but also by inducing anti-inflammatory cytokines in the WAT and liver, both of which are important peripheral tissues affecting insulin resistance. The effect of Aloe QDM complex in the WAT and liver are related to its dual action on PPARgamma and 11beta-HSD1 expression and its use as a nutritional intervention against T2D and obesity-related inflammation is suggested.
11-beta-Hydroxysteroid Dehydrogenase Type 1 ; Aloe ; Animals ; Blood Glucose ; Blotting, Western ; Cytokines ; Diabetes Mellitus, Type 2 ; Diet ; Diet, High-Fat ; Fasting ; Glucose ; Humans ; Hyperglycemia ; Hyperlipidemias ; Inflammation ; Insulin ; Insulin Resistance ; Liver ; Macrophages ; Male ; Mice ; Mice, Obese ; Obesity ; Plasma ; PPAR gamma ; RNA, Messenger ; Thiazolidinediones ; Triglycerides

OBJECTIVETo study the effect of freeze-dried mouse epidermal growth factor (mEGF) on the expression of peroxisome proliferator-activated receptor &beta; (PPAR-&beta;) in mice during wound healing.

METHODSFull-thickness skin defect with area of 1.5 cm × 1.5 cm was reproduced on both sides of the back of 70 BALB/c mice (2 wounds in each mouse). The wound on the left side in each mouse was treated with 5 µg/mL mEGF solution (experiment group), and that on the right side in each mouse was treated with saline (control group). On post injury day (PID) 7, 11, and 16, 20 mice were used for determination of wound healing rate at each time point. On PID 1, 3, 7, 11, 14, and 18, specimens of wound edge were harvested for determination of protein and gene expression of PPAR-&beta; with immunohistochemical staining and in situ hybridization, with 10 specimens at each time point (denoted as integral absorbance value). Data were processed with t test.

RESULTS(1) Wound healing rate. The wound healing rate in experiment group on PID 7, 11, and 16 was respectively higher than that in control group (with t value respectively 3.03, 6.05, 11.9, P values all below 0.01). (2) Immunohistochemical observation. In both groups, the PPAR-&beta; proteins highly expressed in fibroblasts of wound granulation tissues and nuclei of keratinocytes located in wound edge at early stage after injury, and they highly expressed in newly formed epidermis and their fibroblasts in the lower layer after wound epithelization. The expression of PPAR-&beta; protein was gradually decreased after wound healing. The expression of PPAR-&beta; protein at each time point in experiment group was respectively higher than that in control group (with t values from 2.15 to 7.37, P < 0.05 or P < 0.01). The expression of PPAR-&beta; protein peaked on PID 3 in experiment group [(3.46 ± 1.33) × 10(3)], which was (2.35 ± 1.09) × 10(3) in control group. (3) In situ hybridization. The expression levels of PPAR-&beta; mRNA in both groups were up-regulated after injury, which were mainly observed in fibroblasts of wound and cytoplasm of KC in wound edge, but they were down-regulated after wound epithelization. The expression of PPAR-&beta; mRNA at each time point in experiment group was respectively higher than that in control group (with t values from 2.35 to 6.64, P < 0.05 or P < 0.01). The expression of PPAR-&beta; mRNA in both groups peaked on PID 3 [(7.3 ± 2.6) × 10(6), (4.5 ± 3.0) × 10(6), respectively].

CONCLUSIONSmEGF can up-regulate the expression of PPAR-&beta; in wound tissue of mice and promote wound healing.

Animals ; Epidermal Growth Factor ; pharmacology ; Female ; Granulation Tissue ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; PPAR-beta ; metabolism ; Skin ; injuries ; metabolism ; Wound Healing ; drug effects