Fibroblast Collagen Secretion Research Articles

Wettability and biological responses of titanium surface's biomimetic hexagonal microstructure.

In this research, an experiment was conducted on how the surface wettability and biocompatibility of staplers' titanium nails impact the healing of gastrointestinal tissue. Firstly, the bionic hexagonal structure was prepared on the surface of Ti metal by laser processing technology, and the laser textured titanium samples were observed by scanning electron microscope. Then, the liquid-solid contact angle-measuring instrument was used to characterize the wettability of titanium samples. Finally, cells were cultured on the surface of different titanium samples, CCK8 assay and qRT-PCR were carried out to investigate cell adhesion and collagen secretion on the surface of different samples. The results showed that the bionic hexagonal surface increased the surface roughness, reduced the liquid-solid contact angle, and promoted the adhesion and collagen secretion of fibroblasts. The increased wettability provided a better growth environment for cell growth. Microtexture is an important factor affecting the behavior of cells and its size parameters regulate cell gene expression, which is worthy of further study.

Dapagliflozin alleviates cardiac fibrosis through suppressing EndMT and fibroblast activation via AMPKα/TGF-β/Smad signalling in type 2 diabetic rats.

Diabetic cardiomyopathy (DCM) is one of the leading causes of heart failure in patients with diabetes mellitus, with limited effective treatments. The cardioprotective effects of sodium‐glucose cotransporter 2(SGLT2) inhibitors have been supported by amounts of clinical trials, which largely fills the gap. However, the underlying mechanism still needs to be further explored, especially in terms of its protection against cardiac fibrosis, a crucial pathophysiological process during the development of DCM. Besides, endothelial‐to‐mesenchymal transition (EndMT) has been reported to play a pivotal role in fibroblast multiplication and cardiac fibrosis. This study aimed to evaluate the effect of SGLT2 inhibitor dapagliflozin (DAPA) on DCM especially for cardiac fibrosis and explore the underlying mechanism. In vivo, the model of type 2 diabetic rats was built with high‐fat feeding and streptozotocin injection. Untreated diabetic rats showed cardiac dysfunction, increased myocardial fibrosis and EndMT, which was attenuated after treatment with DAPA and metformin. In vitro, HUVECs and primary cardiac fibroblasts were treated with DAPA and exposed to high glucose (HG). HG‐induced EndMT in HUVECs and collagen secretion of fibroblasts were markedly inhibited by DAPA. Up‐regulation of TGF‐β/Smad signalling and activity inhibition of AMPKα were also reversed by DAPA treatment. Then, AMPKα siRNA and compound C abrogated the anti‐EndMT effects of DAPA in HUVECs. From above all, our study implied that DAPA can protect against DCM and myocardial fibrosis through suppressing fibroblast activation and EndMT via AMPKα‐mediated inhibition of TGF‐β/Smad signalling.

The electrostimulation and scar inhibition effect of chitosan/oxidized hydroxyethyl cellulose/reduced graphene oxide/asiaticoside liposome based hydrogel on peripheral nerve regeneration in vitro.

The application of hollow nerve conduits in the repair of peripheral nerve defects is effected by inferior recovery, and nerve extension is hampered by the scar tissue generated during the repair process. In this study, the filler in hollow nerve conduit, chitosan/oxidized hydroxyethyl cellulose (CS/OHEC) hydrogel loaded asiaticoside liposome and the conductive reduced graphene oxide (rGO) were developed and used to reform the microenvironment for peripheral nerve regeneration. The physiochemical properties of CS/OHEC/rGO/asiaticoside liposome hydrogel were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and compressive modulus, porosity, swelling ratio, degradation and conductivity. In addition, the asiaticoside release profiles in vitro were investigated. The hydrogel had a continuous porous network structure with pore size distribution in the range of 50-250μm. The majority of the hydrogels had porosities above 70%, and a compressive modulus of 0.45MPa. The weight loss rate of hydrogel reached 76.14±4.45% within 8weeks. The conductivity of the hydrogel was 5.27±0.42×10-4S/cm. The hydrogel was non-toxic and suitable for adhesion and proliferation of nerve cells in vitro. In addition, the application of electrical stimulation after the addition of rGO can promote the differentiation and proliferation of nerve cells, accelerating nerve regeneration. The asiaticoside released from the hydrogel had a significant inhibitory effect on the growth and collagen secretion of fibroblasts, eliminating scars for regenerative nerves, which can promote the function recovery of defected peripheral nerve. Together, these positive results indicate that the hydrogel would be a promising candidate for peripheral nerve regeneration.

The KCa3.1 blocker TRAM-34 inhibits proliferation of fibroblasts in paraquat-induced pulmonary fibrosis

KCa3.1, a Ca2+-activated K+ channel, plays an important role in modulating calcium signaling and maintaining membrane potential during cell activation. It has been reported to promote fibroblast function in many fibrotic diseases. However, the role of KCa3.1 in the pathophysiology of pulmonary fibrosis after paraquat (PQ) poisoning has not been studied. A rat model of PQ poisoning was used. After treatment with TRAM-34, which is a highly selective KCa3.1 blocker, the expression of KCa3.1, TGF-β1 and α-SMA were evaluated via Western blot, histology and other assays. Bromodeoxyuridine (BrdU) marking and MTT assay were used to measure primary rat pulmonary fibroblast proliferation. The results showed that KCa3.1 expression was elevated after PQ poisoning. Blockade of KCa3.1 alleviated PQ-induced pulmonary inflammation and fibrosis. Blockade of KCa3.1 also attenuated the level of collagen I and α-SMA and the proliferation of fibroblasts. However, TGF-β1 expression remained unaffected by blockade of KCa3.1 in rat lung tissues after PQ poisoning. The present study suggests that KCa3.1 expression increased and might promote pulmonary fibroblast proliferation in PQ-induced pulmonary fibrosis. In addition, we confirmed that TRAM-34 attenuates proliferation and collagen secretion of fibroblasts. Our findings indicated that TRAM-34 might inhibit PQ-induced proliferation of pulmonary fibroblasts and prevent progression of lung fibrosis.

Polysaccharides of St. John’s Wort Herb Stimulate NHDF Proliferation and NEHK Differentiation via Influence on Extracellular Structures and Signal Pathways

St. John's Wort herb extracts often contain undesirable or volitional polysaccharides. As polysaccharides exhibit structure-dependent biological functions in the present study water-soluble polysaccharides were extracted from herb material, fractionated by anion exchange chromatography into four main polysaccharide fractions (denominated as Hp1, Hp2, Hp3 and Hp4) and characterized by HPAEC-PAD, CE, IR and GC-MS. Biological activity on human skin keratinocytes and fibroblasts was assessed by investigation of their effect on proliferation, metabolism, cytotoxicity, apoptosis and differentiation. The underlying mechanisms were investigated in gene expression studies. Polysaccharide fraction Hp1 was mainly composed of β-D-glucose. Hp2, Hp3 and Hp4 contained pectic structures and arabinogalactan proteins varying in composition and quantity. Polysaccharides of Hp1 induced the keratinocyte differentiation by inhibiting the gene expression of the epidermal growth factor and insulin receptor. While the collagen secretion of fibroblasts was stimulated by each polysaccharide fraction only Hp1 stimulated the synthesis. The fibroblast proliferation was reduced by Hp1 and increased by Hp4. This effect was related to the influence on genes that referred to oxidative stress, metabolism, transcription processes and extracellular proteins. In conclusion polysaccharides have been shown as biologically active ingredients of aqueous St. John's Wort extracts with a relation between their structural characteristics and function.

Effects of adrenomedullin on aldosterone-induced cell proliferation in rat cardiac fibroblasts

Aldosterone induces cardiac remodeling in cardiovascular diseases by stimulating the proliferation, production and secretion of collagen in fibroblasts. It also stimulates vascular smooth muscle cells to produce and secrete adrenomedullin (ADM), which has a cytoprotective effect against cardiovascular damage. We examined the effect of aldosterone on ADM production and secretion in rat cardiac fibroblasts, and the effect of ADM on aldosterone-stimulated fibroblast proliferation to observe the interaction between endogenous ADM and aldosterone. We detected ADM produced and secreted from cultured cardiac fibroblasts and the intracellular cAMP level by radioimmunoassay; evaluated cell proliferation by the level of [3H]-thymine incorporation; measured preproADM gene expression by reverse transcriptase polymerase chain reaction (RT-PCR); and monitored extracellular signal related kinase (ERK) activity by the phosphorylation of myelin basic protein in the presence of [gamma-32P] ATP. Our results showed that aldosterone-stimulated secretion of ADM and its mRNA expression were concentration-dependent, which could be inhibited by the specific antagonist of mineralocorticoid receptor, spironolactone. In contrast, ADM inhibited aldosterone-induced fibroblast proliferation and ERK activity. Treatment with ADM24-50 (a new antagonist of specific ADM receptors) and calcitonin gene-related peptide (CGRP)8-37 (the antagonist of CGRP receptor type 1), to attenuate the action of endogenous ADM, reinforced the aldosterone-induced proliferation and inhibited the intracellular cAMP production stimulated by aldosterone. Thiorphan, an inhibitor of ADM degradation, inhibited the [3H]-thymine incorporation and reinforced the intracellular cAMP level induced by aldosterone. We reach the conclusion that aldosterone stimulates rat cardiac fibroblasts to produce and secrete ADM, which in turn regulates the proliferation-induced effects of aldosterone in these cells.

Altered response of intestinal mucosal fibroblasts to profibrogenic cytokines in inflammatory bowel disease.

Fibrosis is a major complication of inflammatory bowel disease (IBD), which may be mediated by the intestinal fibroblast. Our aim was to isolate and characterize mucosal fibroblasts from histologically normal intestine (control), ulcerative colitis (UC), inflamed Crohn's disease (CD), and fibrosed CD intestine. Fibroblasts were characterized by light and electron microscopy and immunohistochemistry. Fibroblast collagen secretion and proliferation were determined by 3H-proline and 3H-thymidine incorporation, and the effects of exposure to interleukin (IL)-1beta, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF)-beta1, insulin-like growth factor (IGF)-1, and macrophage colony stimulating factor (M-CSF) were determined. No difference in doubling time was observed between the fibroblast populations from UC and CD intestine. All proliferated faster than fibroblasts from control intestine. Collagen secretion from IBD fibroblasts, independent of type, was increased compared with control fibroblasts and PDGF, bFGF, and TGF-beta1-induced collagen secretion from IBD fibroblasts. These results suggest the presence of an activated subpopulation of fibroblasts in both UC and CD tissue irrespective of the presence of tissue fibrosis or disease type.