Ischemia and reperfusion impair the gene expression of endogenous basic fibroblast growth factor (bFGF) in rat skeletal muscles

Roles of extracellular signal-regulated kinase 1/2 on the suppression of myostatin gene expression induced by basic fibroblast growth factor

Basic fibroblast growth factor (bFGF, FGF-2) has an inhibitory effect on the expression of the myostatin gene in murine C2C12 myoblasts, as shown in our recent investigation. To further verify the regulatory effects of bFGF on the myostatin gene and to better understand its mechanism in skeletal muscle, and to promote clinical applications of bFGF to treat skeletal muscle diseases correlated to muscular dystrophy or AIDS and so on, recombinant human bFGF (rh-bFGF) was added into media and stimulated murine C2C12 myoblasts to investigate the dose-dependent effect of bFGF on suppression of myostatin gene expression and the role of extracellular signal-regulated kinase 1/2 (ERK1/2) in the regulatory mechanism. Simultaneously, complete coding sequence of ovine?8 kDa-bFGF gene was inserted into eukaryotic vector pCMV-neo (originated from pEGFP-N1 vector, from which the EGFP gene has been removed), the recombinant plasmid pCMV-neo-bFGF was harvested and injected into the mouse skeletal muscle of posterior limb. Expression levels of bFGF, myostatin, and ERK1/2 genes in murine C2C12 myoblasts and the skeletal muscle were analyzed by real-time reverse transcription-polymerase chain reaction and Western blotting analysis, respectively. The results showed that bFGF impaired the expression of myostatin gene in a dose-dependent manner in C2C12 cells, with increasing concentration of rh-bFGF, myostatin mRNA declined gradually. In addition, results in skeletal muscle indicated that bFGF also suppressed the expression of the myostatin gene in vivo. Furthermore, we found ERK1/2 participated in the regulatory mechanism of bFGF on the expression of the myostatin gene.

Profiling of genes differentially expressed in a rat of early and later gestational ages with high-density oligonucleotide DNA array

The early gestational fetus heals dermal wounds rapidly and scarlessly. This phenomenon appears to be intrinsic to fetal skin and is probably modulated by interplay of many genes. We ventured to study differences in gene expression between earlier gestational skin (EGS) and later gestational skin (LGS) with the aid of high-density oligonucleotide DNA array to explore the molecular mechanism underlying scarless healing. Total RNA was isolated from fetal Wistar rat skin of the scarless (E15) and scar-forming (E18) periods of gestation (term=21.5 days), and purified to mRNAs. Both the mRNAs from EGS and LGS were reversely transcribed to cDNAs, and were labeled with the incorporation of fluorescent dCTP for preparing the hybridization probes through single primer amplification reaction and Klenow labeling methods. The mixed probes were then hybridized to the oligonucleotide DNA arrays that contained 5,705 DNA fragments representing 5,705 rat genes. After highly stringent washing, the microarray was scanned for fluorescent signals to display the differentially expressed genes between two groups of tissues. Among 5,705 rat genes, there were 53 genes (0.93%) with differentially expressed levels between EGS and LGS; 27 genes, including fibroblast growth factor 8 and follistatin, were up-regulated (0.47%); and 26 genes, containing lymphoid enhancer binding factor-1 and beta-catenin, were down-regulated (0.46%) in fetal skin of scarless period vs. scar-forming period. Analyses of genes related to ion channels, growth factors, extracellular matrix and cellular skeleton, and movement confirmed that our molecular data obtained by oligonucleotide DNA array were consistent with the published biochemical and clinical findings of fetal scarless healing. Stronger expression of fibroblast growth factor 8, follistatin, and weaker expression of lymphoid enhancer binding factor-1 and beta-catenin in EGS vs. LGS were also testified with reverse transcription-polymerase chain reaction and Western blotting methods. Oligonucleotide DNA array was a powerful tool for investigating different gene expression between scarless and scar-forming periods of gestation in the rat fetal skin. Many genes were involved in the phenotypic transition from scarless to scar-forming wound repair during gestation. Further analysis of the obtained genes will help to understand the molecular mechanism of fetal scarless healing.

Expression of basic fibroblast growth factor results in the decrease of myostatin mRNA in murine C2C12 myoblasts

During the development and regeneration of skeletal muscle, many growth factors, such as basic fibroblast growth factor (bFGF, FGF-2) and myostatin, have been shown to play regulating roles. bFGF contributes to promote proliferation and to inhibit differentiation of skeletal muscle, whereas myostatin plays a series of contrasting roles. In order to elucidate whether the expression of bFGF has any relationship with the expression of myostatin in skeletal muscle cells, we constructed a eukaryotic expression vector for the expression of exogenous bFGF in murine C2C12 myoblasts. Quantitative RT-PCR assays indicated that with the increase of the expression of exogenous bFGF gene, the expression of endogenous myostatin gene was suppressed at mRNA level and protein level.

Engineered growth factors and cutaneous wound healing: Success and possible questions in the past 10 years

In the past 10 years, many engineered growth factors, including recombinant human epidermal growth factor, basic fibroblast growth factor, and platelet-derived growth factor, have been produced and used in the clinic. After screening the results from different centers, some results are found to be encouraging, while others are discouraging. Although the interpretation of these results may depend on your perspective, it may also depend on different criteria, different wounds, and even different aims. In this article, successful experiences and failures concerning the use of growth factors and cutaneous wound healing are summarized. Based on this information and our clinical experience, we address people's concerns such as whether growth factors have altered clinical practice thus far and whether growth factor treatments have solved all problems involved in wound healing. Is there a need for exogenous application of growth factors in acute or chronic wounds, and if so, is it safe to use growth factors to promote wound healing? Last, can we achieve perfect wound healing in those wounds treated with growth factors?

[Free flap pedicle loss: clinical study on 8 cases]

The authors report on 8 cases of free flaps with vascular pedicle disruption that were encountered between postoperative days 8 to 18. In one case, the inflow disappeared 18 months after the transfer without any trouble. This resulted in 2 partial and one complete flap losses. The 4 other flaps survived completely. This complete survival is related to the angiogenesis process coming from the surrounding tissues. The most obvious causal factor responsible for the 2 partial losses was the coverage of large, non viable areas, such as a prosthetic material and bone deprived of periosteum. The only causal factor that could be assessed in the case of total necrosis was the presence of an immunosuppressive treatment. Variables participating in the installation of an adequate angiogenic response are then discussed in accordance to this experience and to the literature. Limited contact with viable tissue, ischemia-reperfusion or drugs limiting the angiogenesis seems to promote failure when the pedicle is quickly disrupted. Hypoxia seems to be the most important cellular mechanism promoting the angiogenesis in this context.

Vascular growth factor expression in a rat model of severe limb ischemia

BACKGROUND

In ischemic tissue hypoxia induces production of vascular growth factors, especially VEGF, which initiate local angiogenesis. Collateralization-or arteriogenesis-occurs at a distance from the ischemic tissue and depends on different growth factors such as FGF-2. A spatial discrepancy in endogenous growth factor production in limb ischemia may have implications for therapeutic angiogenesis. The present study elucidates if such spatial and temporal variation occurs.

MATERIALS AND METHODS

A two-staged procedure was performed to generate severe long-lasting limb ischemia in 60 rats. At 1, 7, 28, and 56 days, subgroups were subjected to perfusion assessment with laser Doppler imaging and angiography. Muscle samples and foot skin were gathered to measure growth factor expression and signs of angiogenesis using immunohistochemistry.

RESULTS

There was an early twofold increase (P < 0.05) in both VEGF and FGF-2 levels in distal muscle from the ischemic leg, but no significant rise in the thigh. The concentrations decreased over time with an exception for VEGF in soleus and FGF-2 in anterior tibial muscle, which remained high. An increased capillarity was noted (P < 0.05) in soleus after 28 days, and the number of BrdU-positive ECs was elevated in all ischemic samples at 56 days. Collateral arteries were observed on the angiograms after 7 days.

CONCLUSIONS

The results suggest that in limb ischemia any major increase in vascular growth factor production is limited to ischemic tissue. The spatial and temporal distribution patterns of growth factor production are complex and to a great extent influenced by inflammation.

Advances in wound healing research in China: From antiquity to the present

China is the largest developing country in the world with wounds occuring everyday and everywhere, representing one of the main killers of people. Prevention and treatment of wounds are the main tasks for Chinese surgeons. Although wound care and management have a long history in China, wound healing research and management have made significant progress only in recent years. In this article we give a brief account of the history of wound care and management in China. In addition, we introduce the main research fields and achievements in tissue repair and regeneration during recent times in this country. We hope that these works will benefit our foreign colleagues to know our work and enhance the communication among us.

Effect of intestinal ischemia-reperfusion on expressions of endogenous basic fibroblast growth factor and transforming growth factor β in lung and its relation with lung repair

AIM: To study the changes of endogenous transforming growth factor β (TGF-β) and basic fibroblast growth factor (bFGF) in lung following intestinal ischemia and reperfusion injury and their effects on lung injury and repair.

METHODS: Sixty Wistar rats were divided into five groups, which underwent sham-operation, ischemia (45 min), and reperfusion (6, 24 and 48 h, respectively) after ischemia (45 min). Immunohistochemical method was used to observe the localization and amounts of both growth factors.

RESULTS: Positive signals of both growth factors could be found in normal lung, mainly in alveolar cells and endothelial cells of vein. After ischemia and reperfusion insult, expressions of both growth factors were increased and their amounts at 6 h were larger than those of normal control or of 24 and 48 h after insult.

CONCLUSION: The endogenous bFGF and TGF-βexpression appears to be up-regulated in the lung following intestinal ischemia and reperfusion, suggesting that both growth factors may be involved in the process of lung injury and repair.