Isotonic Biaxial Loading: An Economic, Versatile Method for the Study of Fibroblast-Populated Collagen Gels

1999 ◽  
Author(s):  
Jeffrey W. Holmes ◽  
Thomas K. Borg
Keyword(s):  
Biaxial Loading ◽  
Cardiac Fibroblasts ◽  
Collagen Gel ◽  
Simple System ◽  
Neonatal Rat ◽  
Collagen Gels ◽  
Maximal Contraction ◽  
Contraction Force ◽  
A Value ◽  
Collagen Gel Contraction

Abstract Studies of collagen gel contraction by embedded fibroblasts have characterized the response of free (unloaded) or isometric (maximally loaded) gels but not the response to intermediate loads. An inexpensive, simple system was devised to isotonically load fibroblast-populated collagen gels using freely hanging weights. This system provided excellent repeatability. Maximal contraction force was estimated at 1 mN per million cells in neonatal rat cardiac fibroblasts, a value that agreed well with reported isometric experiments in fibroblasts from other tissues. The ability to load uniaxially or biaxially and with variable loads will facilitate exploration of the regulation of fibroblast mechanics and biology by stress.

scholarly journals Angiotensin II Promotes Integrin-Mediated Collagen Gel Contraction by Adult Rat Cardiac Fibroblasts.

1999 ◽  
Vol 40 (4) ◽  
pp. 461-469 ◽  
Author(s):  
Tatsuya NUNOHIRO ◽  
Naoto ASHIZAWA ◽  
Kristof GRAF ◽  
Willa HSUEH ◽  
Katsusuke YANO
Keyword(s):  
Angiotensin Ii ◽  
Cardiac Fibroblasts ◽  
Collagen Gel ◽  
Adult Rat ◽  
Collagen Gel Contraction

Beta-adrenergic agonists attenuate fibroblast-mediated contraction of released collagen gels

1996 ◽  
Vol 270 (5) ◽  
pp. L829-L835 ◽  
Author(s):  
T. Mio ◽  
Y. Adachi ◽  
S. Carnevali ◽  
D. J. Romberger ◽  
J. R. Spurzem ◽  
...  
Keyword(s):  
Collagen Gel ◽  
Biologically Active ◽  
Dependent Manner ◽  
Collagen Gels ◽  
Adrenergic Agonists ◽  
Concentration Dependent Manner ◽  
Beta Adrenergic ◽  
Cyclic Monophosphate ◽  
Beta Adrenergic Agonists ◽  
Collagen Gel Contraction

The effects of beta-adrenergic agonists on fibroblast-mediated collagen gel contraction were investigated. beta-Agonists isoproterenol and epinephrine significantly attenuated fibroblast-mediated gel contraction in a concentration-dependent manner, whereas alpha-agonist norepinephrine had no effect. The biologically active form of isoproterenol, (-)-isoproterenol, was 10-fold more effective than the optical isoform, (+)-isoproterenol. beta-Antagonists sotalol and propranolol reversed the attenuation caused by 10(-7) M isoproterenol or epinephrine at the concentration of 10(-7) M or 10(-6) M, but the alpha-antagonist phentolamine did not. However, beta1- or beta2-specificity of these effects is not clear. Isobutyl methylxanthine augmented the effect of isoproterenol and also prolonged the duration. Two reagents which are known to increase intracellular adenosine 3',5'-cyclic monophosphate (cAMP), prostaglandin E2 and dibutyryl adenosine 3',5'-cyclic monophosphate, attenuated gel contraction in a concentration-dependent manner. These data suggest that the fibroblast-mediated collagen gel contraction can be modulated by beta-adrenergic agonists and that the effect depends on cAMP.

Sodium nitroprusside augments human lung fibroblast collagen gel contraction independently of NO-cGMP pathway

2000 ◽  
Vol 278 (5) ◽  
pp. L1032-L1038 ◽  
Author(s):  
X. D. Liu ◽  
C. M. Skold ◽  
T. Umino ◽  
J. R. Spurzem ◽  
D. J. Romberger ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Human Lung ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Lung Fibroblast ◽  
Type I ◽  
Collagen Gels ◽  
Human Lung Fibroblast ◽  
Collagen Gel Contraction ◽  
Cgmp Pathway

Nitric oxide (NO) relaxes vascular smooth muscle in part through an accumulation of cGMP in the target cells. We hypothesized that a similar effect may also exist on collagen gel contraction mediated by human fetal lung (HFL1) fibroblasts, a model of wound contraction. To evaluate this, HFL1 cells were cultured in three-dimensional type I collagen gels and floated in serum-free DMEM with and without various NO donors. Gel size was measured with an image analyzer. Sodium nitroprusside (SNP, 100 μM) significantly augmented collagen gel contraction by HFL1 cells (78.5 ± 0.8 vs. 58.3 ± 2.1, P < 0.01), whereas S-nitroso- N-acetylpenicillamine, 5-amino-3-(4-morpholinyl)-1,2,3-oxadiazolium chloride, NONOate, and N G-monomethyl-l-arginine did not affect the contraction. Sodium ferricyanide, sodium nitrate, or sodium nitrite was not active. The augmentory effect of SNP could not be blocked by 1 H-[1,2,4]-oxadiazolo-[4,3- a]-quinoxalin-1-one, whereas it was partially reversed by 8-(4-chlorophenylthio) (CPT)-cGMP. To further explore the mechanisms by which SNP acted, fibronectin and PGE2 production were measured by immunoassay after 2 days of gel contraction. SNP inhibited PGE2 production and increased fibronectin production by HFL1 cells in a concentration-dependent manner. CPT-cGMP had opposite effects on fibronectin and PGE2 production. Addition of exogenous PGE2 blocked SNP-augmented contraction and fibronectin production by HFL1 cells. Therefore, SNP was able to augment human lung fibroblast-mediated collagen gel contraction, an effect that appears to be independent of NO production and not mediated through cGMP. Decreased PGE2 production and augmented fibronectin production may have a role in this effect. These data suggest that human lung fibroblasts in three-dimensional type I collagen gels respond distinctly to SNP by mechanisms unrelated to the NO-cGMP pathway.

scholarly journals Stimulation of collagen gel contraction by angiotensin II and III in cardiac fibroblasts

2002 ◽  
Vol 3 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Paul Lijnen ◽  
Victor Petrov ◽  
Kandelaria Rumilla ◽  
Robert Fagard
Keyword(s):  
Angiotensin Ii ◽  
Cardiac Fibroblasts ◽  
Collagen Gel ◽  
Collagen Gel Contraction ◽  
Stimulation Of

Tetracycline-Based MMP Inhibitors Can Prevent Fibroblast-Mediated Collagen Gel Contraction In Vitro

1998 ◽  
Vol 12 (1) ◽  
pp. 86-93 ◽  
Author(s):  
S.A. Myers ◽  
R.G. Wolowacz
Keyword(s):  
Culture Media ◽  
Collagen Gel ◽  
Collagen Gels ◽  
Cytotoxic Effects ◽  
Chemically Modified ◽  
Tissue Culture Media ◽  
Collagen Gel Contraction ◽  
Chemically Modified Tetracyclines

Collagen gels in vitro can be contracted by fibroblasts. The role of matrix metalloproteinases (MMPs) in the contraction of collagen lattices by human neonatal foreskin fibroblasts (HuFFs) was investigated in tissue culture media supplemented by various doses of known gelatinase inhibitors. Fluorescent assays with model gelatinase substrates and media conditioned by fibroblasts apparently confirmed the ability of chemically modified tetracyclines (CMTs) to act as inhibitors of MMP2, and zymography demonstrated that this was the major cell-derived MMP activity. There were no observable effects on the rate of contraction of attached FPCLs containing 6 x 104 HuFFs (passages 18-25) with either CMT-5 or CMT-2 at all concentrations tested (0-100 μg/mL). However, at greater than 20 μg/mL doxycycline and greater than 5 μg/mL CMT-3, FPCL contraction was completely abolished. Quantitative assessment of cell viability by means of the MTT assay in monolayer and qualitatively within the FPCLs with CalceinAM suggested that differences were not due to cytotoxic effects. Seeding FPCLs with lower-passage fibroblasts produced identical trends. These results may implicate the involvement of MMPs in the process of gel contraction, although tetracyclines have effects additional to their ability to inhibit MMPs directly.

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