scholarly journals Optimized Repopulation of Tendon Hydrogel

Hand ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Simon Farnebo ◽  
Lovisa Farnebo ◽  
Maxwell Kim ◽  
Colin Woon ◽  
Hung Pham ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cellular Proliferation ◽  
Fluorescent Protein ◽  
Synergistic Effects ◽  
Tendon Healing ◽  
Fold Increase ◽  
Control Group ◽  
Sprague Dawley ◽  
Cell Counts

Background: Tendon-derived extracellular matrix (ECM) hydrogel has been shown to augment tendon healing in vivo. We hypothesized that reseeding of the gel with adipose-derived stem cells (ASCs) could further assist repopulation of the gel and that combinations of growth factors (GFs) would improve the survival of these cells after reseeding. Methods: A tendon-specific ECM solution was supplemented with varying concentrations of basic fibroblast growth factor (bFGF), insulin-like growth factor–1 (IGF-1), and platelet-derived growth factor–BB (PDGF-BB). Gels were then seeded with ASCs transfected with a green fluorescent protein/luciferin construct. Cell proliferation was determined using the MTT assay and histology, and GF and ASC augmented gels were injected into the back of Sprague Dawley rats. Bioluminescence of seeded gels was continuously followed after reseeding, and cell counts were performed after the gels were explanted at 14 days. Results: Synergistic effects of the GFs were seen, and an optimal combination was determined to be 10 ng/mL bFGF, 100 ng/mL IGF-1, and 100 ng/mL PDGF-BB (2.8-fold increase; P < .05). In vivo bioluminescence showed an improved initial survival of cells in gels supplemented with the optimal concentration of GF compared with the control group (10.6-fold increase at 8 days; P < .05). Cell counts of explants showed a dramatic endogenous repopulation of gels supplemented by GF + ASCs compared with both gels with GF but no ASCs (7.6-fold increase) and gels with ASCs but no GF (1.6-fold increase). Conclusion: Synergistic effects of GFs can be used to improve cellular proliferation of ASCs seeded to a tendon ECM gel. Reseeding with ASCs stimulates endogenous repopulation of the gel in vivo and may be used to further augment tendon healing.

335 CYTOPLASMIC MICROINJECTION OF EXOGENOUS DNA IN IN VITRO AND IN VIVO DERIVED SHEEP EMBRYOS

2011 ◽  
Vol 23 (1) ◽  
pp. 263
Author(s):  
F. Pereyra-Bonnet ◽  
A. Gibbons ◽  
M. Cueto ◽  
R. Bevacqua ◽  
L. Escobar ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Genetically Modified ◽  
Fold Increase ◽  
Egfp Expression ◽  
Control Group ◽  
Corpora Lutea ◽  
Exogenous Dna ◽  
Frozen Semen

Microinjection of DNA into the male pronucleus is a commonly used method to generate transgenic animals. However, it is only moderately efficient in several species because it requires proper male pronuclear visualisation, which occurs only in a narrow window of time in mice. The cytoplasmic microinjection of exogenous DNA (eDNA) is an alternative method that has not been fully investigated. Our objective was to evaluate if cytoplasmic microinjection of eDNA is capable of producing genetically modified embryos. In vitro and in vivo derived sheep embryos were cytoplasmically microinjected with pCX-EGFP previously incubated (5 min in a PVP droplet) with oolemma-cytoplasm fragments obtained from donor oocytes by microsurgery. A control group using microinjected plasmid alone was included in the in vivo procedure. For in vitro microinjection, IVF embryos were microinjected with circular plasmid with promoter (50 or 500 ng μL–1) or without promoter (50 ng μL–1) at 6 h after fertilization. The IVF was performed following (Brackett and Olliphant 1975 Biol. Reprod. 12, 260–274) with 15 × 106 spermatozoa mL–1, and presumptive zygotes were cultured in SOF. The expression of enhance green fluorescent protein (EGFP) was determined under blue light. For in vivo microinjection, embryos from superovulated sheep (by standard procedures) were recovered and microinjected with 50 ng μL–1 of linearized plasmid without promoter at 12 h after laparoscopic insemination with frozen semen (100 × 106 spermatozoa per sheep). Plasmid without promoter was used to avoid any possible cytotoxic effect produced by EGFP expression. The microinjection of IVF embryos with 50 ng μL–1 of plasmid was the best condition to produce embryos expressing eDNA (n = 96; 46.9% cleaved; 12.2% blastocysts; 53.0 and 4.1% of green embryos and blastocysts, respectively). Variables between the groups with or without promoter IVF were not statistically different (Fisher test: P < 0.05); however, when 500 ng μL–1 was microinjected, no blastocysts were obtained. In the in vivo embryo production group, 111 presumptive zygotes were microinjected (n = 37; with plasmid alone) from 16 donor sheep (11.5 ± 4.0 corpora lutea; 8.4 ± 4.8 presumptive zygotes recovered; 74.3% recovery rate). The mean time from injection to cleavage was 18.0 ± 4.5 h, and the percentage of cleavage and damage (due to the embryo injection) were >70% and <10%, respectively. Fifty-eight good quality embryos were transferred into the oviducts of 19 surrogate ewes; 12 of them are pregnant (63.1%). The presence of green IVF embryos demonstrates that eDNA was transported to the nucleus after cytoplasmic injection. We believe that the multi-fold increase (50- to 100-fold) in plasmid concentration compared with that used by others was the key step to our successful cytoplasmic microinjection. Accordingly, the new/old methodology described in this study provides an easy DNA construct delivery system of interest for the implementation of early reprogramming events. In addition, results obtained in the near future using in vivo cytoplasmic microinjection with high concentrations of eDNA could revalidate this technique for producing genetically modified large animals.

Facilitated migration of cells from a transected peripheral nerve over collagen fibers: in vivo observations

1989 ◽  
Vol 47 ◽  
pp. 888-889
Author(s):  
Arthur J. Wasserman ◽  
Azam Rizvi ◽  
George Zazanis ◽  
Frederick H. Silver
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Collagen Gel ◽  
Collagen Fibers ◽  
Control Group ◽  
Guide Tube ◽  
Sprague Dawley ◽  
Silicone Tube ◽  
Thin Sections

In cases of peripheral nerve damage the gap between proximal and distal stumps can be closed by suturing the ends together, using a nerve graft, or by nerve tubulization. Suturing allows regeneration but does not prevent formation of painful neuromas which adhere to adjacent tissues. Autografts are not reported to be as good as tubulization and require a second surgical site with additional risks and complications. Tubulization involves implanting a nerve guide tube that will provide a stable environment for axon proliferation while simultaneously preventing formation of fibrous scar tissue. Supplementing tubes with a collagen gel or collagen plus extracellular matrix factors is reported to increase axon proliferation when compared to controls. But there is no information regarding the use of collagen fibers to guide nerve cell migration through a tube. This communication reports ultrastructural observations on rat sciatic nerve regeneration through a silicone nerve stent containing crosslinked collagen fibers.Collagen fibers were prepared as described previously. The fibers were threaded through a silicone tube to form a central plug. One cm segments of sciatic nerve were excised from Sprague Dawley rats. A control group of rats received a silicone tube implant without collagen while an experimental group received the silicone tube containing a collagen fiber plug. At 4 and 6 weeks postoperatively, the implants were removed and fixed in 2.5% glutaraldehyde buffered by 0.1 M cacodylate containing 1.5 mM CaCl2 and balanced by 0.1 M sucrose. The explants were post-fixed in 1% OSO4, block stained in 1% uranyl acetate, dehydrated and embedded in Epon. Axons were counted on montages prepared at a total magnification of 1700x. Montages were viewed through a dissecting microscope. Thin sections were sampled from the proximal, middle and distal regions of regenerating sciatic plugs.

Experimental study of the inhibition effect of CXCL12/CXCR4 in malignant pleural mesothelioma

2018 ◽  
Vol 67 (2) ◽  
pp. 338-345 ◽  
Author(s):  
Jianshuang Li ◽  
Tong Li ◽  
Shuo Li ◽  
Lipeng Xie ◽  
Yi-Lin Yang ◽  
...  
Keyword(s):  
Treatment Group ◽  
Malignant Pleural Mesothelioma ◽  
Synergistic Effects ◽  
Control Group ◽  
Pleural Mesothelioma ◽  
Gene Expressions ◽  
Relationship Of ◽  
The Relationship ◽  
Cxcr4 Axis

Previous studies have demonstrated that CXCL12/CXCR4 axis is closely related to tumors such as malignant pleural mesothelioma (MPM). This research was conducted in order to detect whether CXCL12/CXCR4 inhibitors could restrain MPM and have a synergistic effect with chemotherapy, also to investigate the relationship of CXCL12/CXCR4 with other gene expressions in MPM. Forty mice were injected MPM cells and randomly divided into four groups: the PBS (control group), AMD3100 (CXCR4-CXCL12 antagonist), pemetrexed and AMD3100 plus pemetrexed. The mice were treated respectively for duration of 3 weeks. The size, bioluminescence and weight of tumors were measured. The differences between gene expressions in each group were analyzed. The tumor weights of each treatment group were lower than that of the control group (p<0.05). The bioluminescence of the tumor of the AMD3100 treatment group and the AMD3100 plus pemetrexed treatment group were lower than that of the control group (p<0.05), and AMD3100 was shown to have synergistic effects with pemetrexed (p<0.05). Among the 2.5 billion genes, several hundreds of genes expressed differently between groups. Results show that AMD3100 and pemetrexed can inhibit the growth of MPM in vivo, also that there is a better result if both are used together. Our findings suggest that CXCL12/CXCR4 axis affects a certain amount of gene expression in MPM.

Exercise training improves myocardial tolerance to in vivo ischemia-reperfusion in the rat

1998 ◽  
Vol 275 (5) ◽  
pp. R1468-R1477 ◽  
Author(s):  
Scott K. Powers ◽  
Haydar A. Demirel ◽  
Heather K. Vincent ◽  
Jeff S. Coombes ◽  
Hisashi Naito ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Exercise Training ◽  
Endurance Exercise ◽  
Ischemia Reperfusion ◽  
Experimental Studies ◽  
Control Group ◽  
Sprague Dawley ◽  
Endurance Exercise Training ◽  
Nonprotein Thiols

Experimental studies examining the effects of regular exercise on cardiac responses to ischemia and reperfusion (I/R) are limited. Therefore, these experiments examined the effects of endurance exercise training on myocardial biochemical and physiological responses during in vivo I/R. Female Sprague-Dawley rats (4 mo old) were randomly assigned to either a sedentary control group or to an exercise training group. After a 10-wk endurance exercise training program, animals were anesthetized and mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was achieved by a ligature around the left coronary artery; occlusion was maintained for 20 min, followed by a 10-min period of reperfusion. Compared with untrained, exercise-trained animals maintained higher ( P < 0.05) peak systolic blood pressure throughout I/R. Training resulted in a significant ( P < 0.05) increase in ventricular nonprotein thiols, heat shock protein (HSP) 72, and the activities of superoxide dismutase (SOD), phosphofructokinase (PFK), and lactate dehydrogenase. Furthermore, compared with untrained controls, left ventricles from trained animals exhibited lower levels ( P < 0.05) of lipid peroxidation after I/R. These data demonstrate that endurance exercise training improves myocardial contractile performance and reduces lipid peroxidation during I/R in the rat in vivo. It appears likely that the improvement in the myocardial responses to I/R was related to training-induced increases in nonprotein thiols, HSP72, and the activities of SOD and PFK in the myocardium.

scholarly journals Large adipose tissue generation in a mussel-inspired bioreactor of elastic–mimetic cryogel and platelets

2018 ◽  
Vol 9 ◽  
pp. 204173141880863 ◽  
Author(s):  
Qiang Chang ◽  
Junrong Cai ◽  
Ying Wang ◽  
Ruijia Yang ◽  
Malcolm Xing ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Adipose Tissue ◽  
Growth Factor ◽  
Cellular Proliferation ◽  
Platelet Derived Growth Factor ◽  
Control Group ◽  
Vascular Endothelial ◽  
Angiogenic Growth Factors ◽  
Congenital Deformities ◽  
Endothelial Growth Factor

Soft tissue generation, especially in large tissue, is a major challenge in reconstructive surgery to treat congenital deformities, posttraumatic repair, and cancer rehabilitation. The concern is along with the donor site morbidity, donor tissue shortage, and flap necrosis. Here, we report a dissection-free adipose tissue chamber–based novel guided adipose tissue regeneration strategy in a bioreactor of elastic gelatin cryogel and polydopamine-assisted platelet immobilization intended to improve angiogenesis and generate large adipose tissue in situ. In order to have matched tissue mechanics, we used 5% gelatin cryogel as growth substrate of bioreactor. Platelets from the platelet-rich plasma were then immobilized onto the gelatin cryogel with the aid of polydopamine to form a biomimetic bioreactor (polydopamine/gelatin cryogel/platelet). Platelets on the substrate led to a sustained high release in both platelet-derived growth factor and vascular endothelial growth factor compared with non-polydopamine-assisted group. The formed bioreactor was then transferred to a tissue engineering chamber and then inserted above inguinal fat pad of rats without flap dissection. This integrate strategy significantly boomed the vessel density, stimulated cellular proliferation, and upregulated macrophage infiltration. There was a noticeable rise in the expression of dual-angiogenic growth factors (platelet-derived growth factor and vascular endothelial growth factor) in chamber fluid; host cell migration and host fibrous protein secretion coordinated with gelatin cryogel degradation. The regenerated adipose tissue volume gained threefold larger than control group (p < 0.05) with less fibrosis tissue. These results indicate that a big well-vascularized three-dimensional mature adipose tissue can be regenerated using elastic gel, polydopamine, platelets, and small fat tissue.

scholarly journals Hydroxytyrosol Plays Antiatherosclerotic Effects through Regulating Lipid Metabolism via Inhibiting the p38 Signal Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinxin Zhang ◽  
Yating Qin ◽  
Xiaoning Wan ◽  
Hao Liu ◽  
Chao Iv ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Fold Increase ◽  
Heart Tissue ◽  
Control Group ◽  
Atherosclerotic Lesions ◽  
Serum Crp

Purpose. Hydroxytyrosol (HT) processes multiaspect pharmacological properties such as antithrombosis and antidiabetes. The aim of this study was to explore the antistherosclerotic roles and relevant mechanisms of HT. Methods. Male apoE-/- mice were randomly divided into 2 groups: the control group and the HT group (10 mg/kg/day orally). After 16 weeks, blood tissue, heart tissue, and liver tissue were obtained to detect the atherosclerotic lesions, histological analysis, lipid parameters, and inflammation. And the underlying molecular mechanisms of HT were also studied in vivo and in vitro. Results. HT administration significantly reduced the extent of atherosclerotic lesions in the aorta of apoE-/- mice. We found that HT markedly lowered the levels of serum TG, TC, and LDL-C approximately by 17.4% (p=0.004), 15.2% (p=0.003), and 17.9% (p=0.009), respectively, as well as hepatic TG and TC by 15.0% (p<0.001) and 12.3% (p=0.003), respectively, while inducing a 26.9% (p=0.033) increase in serum HDL-C. Besides, HT improved hepatic steatosis and lipid deposition. Then, we discovered that HT could regulate the signal flow of AMPK/SREBP2 and increase the expression of ABCA1, apoAI, and SRBI. In addition, HT reduced the levels of serum CRP, TNF-α, IL-1β, and IL-6 approximately by 23.5% (p<0.001), 27.8% (p<0.001), 18.4% (p<0.001), and 19.1% (p<0.001), respectively, and induced a 1.4-fold increase in IL-10 level (p=0.014). Further, we found that HT might regulate cholesterol metabolism via decreasing phosphorylation of p38, followed by activation of AMPK and inactivation of NF-κB, which in turn triggered the blockade of SREBP2/PCSK9 and upregulation of LDLR, apoAI, and ABCA1, finally leading to a reduction of LDL-C and increase of HDL-C in the circulation. Conclusion. Our results provide the first evidence that HT displays antiatherosclerotic actions via mediating lipid metabolism-related pathways through regulating the activities of inflammatory signaling molecules.

Hyperglycemia modulates angiotensinogen gene expression

2001 ◽  
Vol 281 (3) ◽  
pp. R795-R802 ◽  
Author(s):  
Ilan Gabriely ◽  
Xiao Man Yang ◽  
Jane A. Cases ◽  
Xiao Hui Ma ◽  
Luciano Rossetti ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Resistance ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Suppressive Effect ◽  
Sprague Dawley ◽  
Hexosamine Biosynthetic Pathway ◽  
Obese Rats ◽  
Agt Gene

Elevated plasma angiotensinogen (AGT) levels have been demonstrated in insulin-resistant states such as obesity and type 2 diabetes mellitus (DM2), conditions that are directly correlated to hypertension. We examined whether hyperinsulinemia or hyperglycemia may modulate fat and liver AGT gene expression and whether obesity and insulin resistance are associated with abnormal AGT regulation. In addition, because the hexosamine biosynthetic pathway is considered to function as a biochemical sensor of intracellular nutrient availability, we hypothesized that activation of this pathway would acutely mediate in vivo the induction of AGT gene expression in fat and liver. We studied chronically catheterized lean (∼300 g) and obese (∼450 g) Sprague-Dawley rats in four clamp studies ( n= 3/group), creating physiological hyperinsulinemia (∼60 μU/ml, by an insulin clamp), hyperglycemia (∼18 mM, by a pancreatic clamp using somatostatin to prevent endogenous insulin secretion), or euglycemia with glucosamine infusion (GlcN; 30 μmol · kg−1 · min−1) and equivalent saline infusions (as a control). Although insulin infusion suppressed AGT gene expression in fat and liver of lean rats, the obese rats demonstrated resistance to this effect of insulin. In contrast, hyperglycemia at basal insulin levels activated AGT gene expression in fat and liver by approximately threefold in both lean and obese rats ( P < 0.001). Finally, GlcN infusion simulated the effects of hyperglycemia on fat and liver AGT gene expression (2-fold increase, P < 0.001). Our results support the hypothesis that physiological nutrient “pulses” may acutely induce AGT gene expression in both adipose tissue and liver through the activation of the hexosamine biosynthetic pathway. Resistance to the suppressive effect of insulin on AGT expression in obese rats may potentiate the effect of nutrients on AGT gene expression. We propose that increased AGT gene expression and possibly its production may provide another link between obesity/insulin resistance and hypertension.

Shear stress increases endothelial platelet-derived growth factor mRNA levels

1991 ◽  
Vol 260 (2) ◽  
pp. H642-H646 ◽  
Author(s):  
H. J. Hsieh ◽  
N. Q. Li ◽  
J. A. Frangos
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Growth Factor ◽  
Umbilical Vein ◽  
Fold Increase ◽  
Platelet Derived Growth Factor ◽  
Mrna Levels ◽  
Cell Mitogen ◽  
Stress Dependent

We have investigated the effect of shear stress on platelet-derived growth factor (PDGF) A and B chain mRNA levels in cultured human umbilical vein endothelial cells (hUVEC). The levels of both PDGF A and B mRNA in hUVEC were increased by a physiological shear stress (16 dyn/cm2), reaching a maximum approximately 1.5-2 h after the onset of shear stress and returning almost to control values at 4 h. The peak levels showed a more than 10-fold enhancement for PDGF A mRNA and a 2- to 3-fold increase for PDGF B mRNA (P less than 0.05). PDGF A mRNA also showed a shear-dependent increase from 0 to 6 dyn/cm2 (P less than 0.05) and then plateaued from 6 to 51 dyn/cm2. PDGF B mRNA levels were elevated as shear stress increased from 0 to 6 dyn/cm2 then declined gradually to a minimum at 31 dyn/cm2 (P less than 0.05) and increased again when shear stress rose to 51 dyn/cm2 (P less than 0.05). PDGF, a potent smooth muscle cell mitogen and vasoconstrictor, released from the endothelium may regulate the blood flow in vivo. The shear stress-dependent elevation of PDGF A and B mRNA in endothelial cells may be involved in the adaptation of blood vessels to flow mediated by the endothelium.

Effect of rhPDGF-BB-Coated Sutures on Tendon Healing in a Rat Model: A Histological and Biomechanical Study

2011 ◽  
Author(s):  
S. Cummings ◽  
J. Dines ◽  
C. K. Hee ◽  
H. K. Kestler ◽  
C. M. Roden ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tissue Repair ◽  
Tendon Repair ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Biomechanical Study ◽  
Growth Factor Delivery ◽  
Delivery Method

Delivering growth factors to the site of injury using a coated suture delivery method has been investigated recently as a means to augment tissue repair [1]. This is a practical approach for growth factor delivery, as sutures are the method of choice for most orthopaedic surgeons for soft tissue repairs. One advantage of growth factor-coated sutures in tendon repair is the potential to accelerate healing in vivo, thereby improving the outcome of the repair. In particular, platelet-derived growth factor-BB (PDGF-BB) is a well characterized wound healing protein known to be chemotactic and mitogenic for cells of mesenchymal origin, including tenocytes, and has been shown to improve healing when applied to animal models of tendon injury [2,3]. The aim of this study was to compare the quality of the tendon repair at four weeks post treatment with sutures coated with varying concentrations of rhPDGF-BB, relative to buffer-coated suture repairs.

Inhibitory Effect of Resveratrol on the Pharmacokinetics of Ticagrelor in Vivo and Vitro

2021 ◽  
Author(s):  
Peng Wang ◽  
Xiao-Xia Hu ◽  
Ying-hui Li ◽  
Nan-Yong Gao ◽  
Guo-quan Chen ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Control Group ◽  
Rat Liver Microsomes ◽  
Sprague Dawley ◽  
Group B

This study was to evaluate the effect of resveratrol on the pharmacokinetics of ticagrelor in rats and the metabolism of ticagrelor in human CYP3A4 and liver microsomes. Eighteen Sprague-Dawley rats were randomly divided into three groups: group A (control group), group B (50mg/kg resveratrol), and group C (150mg/kg resveratrol ). After 30 minutes administration of resveratrol, a single dose of ticagrelor (18mg/kg) was administered orally. The vitro experiment was performed to examine the influence of resveratrol on ticagrelor metabolism in CYP3A4*1, human, and rat liver microsomes. Serial biological samples were assayed by validated UHPLC-MS/MS methods. In vivo study, the AUC and Cmax of ticagrelor in group B and C appeared to be significantly higher than the control group, while Vz/F and CLz/F of ticagrelor in group B and C were significantly decreased. In vitro study, resveratrol exhibited an inhibitory effect on CYP3A4*1, human and rat liver microsomes. The IC50 values of resveratrol were 56.75μM，69.07μM and 14.22μM, respectively. Our results indicated that resveratrol had a inhibitory effect on the metabolism of ticagrelor in vitro and vivo. It should be paid more attention to the clinical combination of resveratrol with ticagrelor and ticagrelor plasma concentration should be monitored to avoid the occurrence of adverse reaction.

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