scholarly journals Effects of Local Opioid Antagonist on Diabetic Fracture Rat Model

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0017
Author(s):  
Jarrett D. Cain ◽  
Michelle Titunick ◽  
Patricia McLaughlin ◽  
Ian Zagon
Keyword(s):  
Growth Factor ◽  
Fracture Healing ◽  
Bone Healing ◽  
Calcium Sulfate ◽  
Bone Fractures ◽  
Diabetic Rats ◽  
Receptor Expression ◽  
Opioid Antagonist ◽  
Diabetic Patients ◽  
Opioid Growth Factor

Category: Diabetes Introduction/Purpose: Complications associated with the diabetes include increased incidence of fracture healing, delayed fracture healing, delayed osteoblasts cell replication, decreased angiogenesis, migration and/or osteoblast cell differentiation. The cellular events involved in bone healing are adversely affected by diabetes; however, can be modulated by the Opioid Growth Factor (OGF)–OGF receptor (OGFr) is an inhibitory peptide that downregulates DNA synthesis in a tissue nonspecific manner. Diabetes is associated with elevated serum levels of OGF and dysregulation of the OGFr leading to multiple complications related to healing, sensitivity, and regeneration. This study explores the presence and function of the OGF-OGFr axis in bone tissue from type 1 diabetic rats examining intact and fractured femurs during early phases of the repair process Methods: Seven-week-old Sprague Dawley rats were injected with streptozotocin (40mg/kg i.p.) to induce T1D; other rats received buffer only and served as controls. After one month, hyperglycemia rats underwent surgery to produce a fracture at the distal third of the femur. Four diabetic rats received opioid antagoinist (naltrexone) and calcium sulfate and all remaining rats received calcium sulfate with water only. X-rays were taken immediately after surgery and after rats were euthanized on post-surgery; femur and tibia were collected for protein isolation, western blot analysis along with frozen or paraffin-embedded for histological analysis Results: Immunofluorescence indicated approximately 90% increase in opioid growth factor receptor expression in diabetic femurs compared to age-matched normal femurs. Western Blotting also suggested an increase in the receptor protein in diabetic bones relative to normal bone. TRAP staining for osteoclasts was greater in control and opioid antagonist-treated diabetic fractures when compared to the number of osteoclasts in vehicle-treated diabetic fractured femurs. Safranin O stained sections revealed approximately more bone in opioid growth receptor antagonist-treated diabetic bone fractures than in vehicle-treated bone fractures Conclusion: These data support our hypothesis that expression levels of OGFr are dysregulated in the bone of diabetic patients leading to complications in bone healing. Moreover, modulation of the OGF-OGFr pathway with receptor antagonists restored some aspects of bone healing. With further study, these preliminary results support the role of the OGF-OGFr axis in treatment of diabetic bone healing. New therapies to target dysregulation of the OGF-OGFr regulatory pathway in diabetes would provide a safe and effective disease-modifying treatment for delayed bone healing.

Fracture Healing and Biomarker Expression in a Diabetic Zucker Rat Model

2014 ◽  
Vol 104 (5) ◽  
pp. 428-433 ◽  
Author(s):  
Javier La Fontaine ◽  
Nathan A. Hunt ◽  
Stacey Curry ◽  
Tyler Kearney ◽  
Daniel Jupiter ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Fracture Healing ◽  
Bone Healing ◽  
Rat Model ◽  
Healing Process ◽  
Diabetic Rats ◽  
Vascular Endothelial ◽  
Delayed Healing ◽  
Endothelial Growth Factor

Background Persons with diabetes have a higher incidence of fractures compared with persons without diabetes. However, there is little published information concerning the deleterious effect of late-stage diabetes on fracture healing. There are no studies using animal models that evaluate the effect of advanced diabetes on fracture healing. The purpose of our study was to evaluate cytokine expression, specifically macrophage inflammatory protein 1 (MIP-1) and vascular endothelial growth factor, in fracture healing in a type 2 diabetes rat model. Methods We evaluated biomarker expression after femur fracture using a rat model. The two groups consisted of 24 Zucker diabetic rats (study group) and 12 Zucker lean rats (control group). An independent reviewer was used to assess delayed union. We evaluated serum samples 2, 4, 7, and 14 days after surgery for MIP-1, vascular endothelial growth factor, leptin, and other cytokine levels. Results At 3 weeks, Kaplan-Meier estimates showed that 45.8% of femur fractures in Zucker diabetic rats had healed, whereas 81.8% of those in Zucker lean rats had healed (P = .02). A logistic regression model to predict fast healing that included the three cytokines and diabetes status showed that the only factor achieving significance was MIP-1α. Vascular endothelial growth factor was the only biomarker to show significance compared with delayed healing. Conclusions These results confirm significant differences in biomarker expression between diabetic and nondiabetic rats during bone healing. The key factors for bone healing may appear early in the healing process, whereas differences in diabetes versus nondiabetes are seen later in the healing process. Increased levels of MIP-1α were associated with the likelihood of delayed healing.

scholarly journals An NIR-Triggered Au Nanocage Used for Photo-Thermo Therapy of Chronic Wound in Diabetic Rats Through Bacterial Membrane Destruction and Skin Cell Mitochondrial Protection

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiaxin Ding ◽  
Binbin Gao ◽  
Zhenhua Chen ◽  
Xifan Mei
Keyword(s):  
Oxidative Stress ◽  
Wound Healing ◽  
Growth Factor ◽  
Diabetic Rats ◽  
Diabetic Patients ◽  
Human Umbilical Cord ◽  
Bacterial Membrane ◽  
Bacterial Membranes ◽  
Skin Cell ◽  
Diabetic Wounds

Bacterial infection and its severe oxidative stress reaction will cause damage to skin cell mitochondria, resulting in long-lasting wound healing and great pain to patients. Thus, delayed wound healing in diabetic patients with Staphylococcus aureus infection is a principal challenge worldwide. Therefore, novel biomaterials with multifunction of bacterial membrane destruction and skin cell mitochondrial protection are urgently needed to be developed to address this challenge. In this work, novel gold cage (AuNCs) modified with epigallocatechin gallate (EGCG) were prepared to treat delayed diabetic wounds. The results showed that Au-EGCG had a high and stable photothermal conversion efficiency under near-infrared irradiation, and the scavenging rate of Au-EGCG for S. aureus could reach 95%. The production of large amounts of reactive oxygen species (ROS) leads to the disruption of bacterial membranes, inducing bacterial lysis and apoptosis. Meanwhile, Au-EGCG fused into hydrogel (Au-EGCG@H) promoted the migration and proliferation of human umbilical cord endothelial cells, reduced cellular mitochondrial damage and oxidative stress in the presence of infection, and significantly increased the basic fibroblast growth factor expression and vascular endothelial growth factor. In addition, animal studies showed that wound closure was 97.2% after 12 days of treatment, and the healing of chronic diabetic wounds was significantly accelerated. Au-EGCG nanoplatforms were successfully prepared to promote cell migration and angiogenesis in diabetic rats while removing S. aureus, reducing oxidative stress in cells, and restoring impaired mitochondrial function. Au-EGCG provides an effective, biocompatible, and multifunctional therapeutic strategy for chronic diabetic wounds.

scholarly journals PPARβ/δ accelerates bone regeneration in diabetic mellitus by enhancing AMPK/mTOR pathway-mediated autophagy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Miao Chen ◽  
Dian Jing ◽  
Rui Ye ◽  
Jianru Yi ◽  
Zhihe Zhao
Keyword(s):  
Bone Regeneration ◽  
Osteogenic Differentiation ◽  
Bone Healing ◽  
High Glucose ◽  
Diabetic Rats ◽  
Diabetic Patients ◽  
Regulatory Effect ◽  
Compound C ◽  
High Glucose Condition ◽  
Glucose Condition

Abstract Background Diabetic patients are more vulnerable to skeletal complications. Peroxisome proliferators-activated receptor (PPAR) β/δ has a positive regulatory effect on bone turnover under physiologic glucose concentration; however, the regulatory effect in diabetes mellitus has not been investigated yet. Herein, we explored the effects of PPARβ/δ agonist on the regeneration of diabetic bone defects and the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) under a pathological high-glucose condition. Methods We detected the effect of PPARβ/δ agonist on osteogenic differentiation of rBMSCs in vitro and investigated the bone healing process in diabetic rats after PPARβ/δ agonist treatment in vivo. RNA sequencing was performed to detect the differentially expressed genes and enriched pathways. Western blot was performed to detect the autophagy-related protein level. Laser confocal microscope (LSCM) and transmission electron microscope (TEM) were used to observe the formation of autophagosomes. Results Our results demonstrated that the activation of PPARβ/δ can improve the osteogenic differentiation of rBMSCs in high-glucose condition and promote the bone regeneration of calvarial defects in diabetic rats, while the inhibition of PPARβ/δ alleviated the osteogenic differentiation of rBMSCs. Mechanistically, the activation of PPARβ/δ up-regulates AMPK phosphorylation, yielding mTOR suppression and resulting in enhanced autophagy activity, which further promotes the osteogenic differentiation of rBMSCs in high-glucose condition. The addition of AMPK inhibitor Compound C or autophagy inhibitor 3-MA inhibited the osteogenesis of rBMSCs in high-glucose condition, suggesting that PPARβ/δ agonist promotes osteogenic differentiation of rBMSCs through AMPK/mTOR-regulated autophagy. Conclusion In conclusion, our study demonstrates the potential role of PPARβ/δ as a molecular target for the treatment of impaired bone quality and delayed bone healing in diabetic patients for the first time.

scholarly journals An Improved Methodology to Evaluate Cell and Molecular Signals in the Reparative Callus During Fracture Healing

2020 ◽  
Vol 68 (3) ◽  
pp. 199-208
Author(s):  
Anuradha Valiya Kambrath ◽  
Justin N. Williams ◽  
Uma Sankar
Keyword(s):  
Fracture Healing ◽  
Bone Healing ◽  
High Throughput Screening ◽  
Molecular Mechanisms ◽  
Structural Integrity ◽  
Bone Fractures ◽  
Early Stage ◽  
Antigen Retrieval ◽  
Sample Collection ◽  
Immunofluorescence Labeling

Approximately 5% to 10% of all bone fractures do not heal completely, contributing to significant patient suffering and medical costs. Even in healthy individuals, fracture healing is associated with significant downtime and loss of productivity. However, no pharmacological treatments are currently available to promote efficient bone healing. A better understanding of the underlying molecular mechanisms is crucial for developing novel therapies to hasten healing. The early reparative callus that forms around the site of bone injury is a fragile tissue consisting of shifting cell populations held together by loose connective tissue. The delicate callus is challenging to section and is vulnerable to disintegration during the harsh steps of immunostaining, namely, decalcification, deparaffinization, and antigen retrieval. Here, we describe an improved methodology for processing early-stage fracture calluses and immunofluorescence labeling of the sections to visualize the temporal (timing) and spatial (location) patterns of cellular and molecular events that regulate bone healing. This method has a short turnaround time from sample collection to microscopy as it does not require lengthy decalcification. It preserves the structural integrity of the fragile callus as the method does not entail deparaffinization or harsh methods of antigen retrieval. Our method can be adapted for high-throughput screening of drugs that promote efficacious bone healing:

scholarly journals Internalization of the opioid growth factor, [Met5]-enkephalin, is dependent on clathrin-mediated endocytosis for downregulation of cell proliferation

2010 ◽  
Vol 299 (3) ◽  
pp. R774-R785 ◽  
Author(s):  
Fan Cheng ◽  
Patricia J. McLaughlin ◽  
William A. Banks ◽  
Ian S. Zagon
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Wound Repair ◽  
Opioid Antagonist ◽  
Live Cells ◽  
Inhibitory Peptide ◽  
African Green Monkey Kidney ◽  
Initial Exposure ◽  
Opioid Growth Factor

The opioid growth factor (OGF; [Met5]-enkephalin), a constitutively expressed and tonically active inhibitory peptide, interacts with the OGF receptor (OGFr) to form an endogenous growth-regulating pathway in homeostasis. Amplification of OGF-OGFr interfacing in animal and clinical studies depresses development, neoplasia, angiogenesis, and immunity. Disruption of the OGF-OGFr axis accelerates cell proliferation and has been particularly important in wound repair. To investigate how OGF enters cells, OGF was labeled with 5,6-tetramethylrhodamine OGF (RhoOGF) to study its uptake in live cells. African green monkey kidney cells (COS-7) incubated with RhoOGF exhibited a temperature-dependent course of entry, being internalized at 37°C but not at 4°C. RhoOGF was detected in the cytoplasm 15 min after initial exposure, observed in both cytoplasm and nucleus within 30 min, and remained in the cells for as long as 5 h. A 100-fold excess of OGF or the opioid antagonist naltrexone, but not other opioid ligands (some selective for classic opioid receptors), markedly reduced entry of RhoOGF into cells. RhoOGF was functional because DNA synthesis in cells incubated with RhoOGF (10−5 to 10−8 M) was decreased 24–36%, and was comparable to cells treated with unlabeled OGF (reductions of 26–39%). OGF internalization was dependent on clathrin-mediated endocytosis, with addition of clathrin siRNA diminishing the uptake of RhoOGF and upregulating DNA synthesis. RhoOGF clathrin-mediated endocytosis was unrelated to endosomal or Golgi pathways. Taken together, these results suggest that OGF enters cells by active transport in a saturable manner that requires clathrin-mediated endocytosis.

Opioid growth factor is present in human and mouse gastrointestinal tract and inhibits DNA synthesis

1997 ◽  
Vol 272 (4) ◽  
pp. R1094-R1104
Author(s):  
I. S. Zagon ◽  
Y. Wu ◽  
P. J. McLaughlin
Keyword(s):  
Circadian Rhythm ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Dna Synthesis ◽  
Opioid Antagonist ◽  
Receptor Interaction ◽  
Esophageal Epithelium ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Opioid Growth Factor

Native opioid peptides serve as growth factors in a number of normal and neoplastic cells and tissues. This study investigated the influence of opioids on circadian rhythm-dependent DNA synthesis in mouse esophagus during homeostatic renewal. In contrast to a labeling index (LI) of 24.0% at 0630 and 5.5% at 1600, disruption of opioid-receptor interaction by the potent opioid antagonist naltrexone hydrochloride (NTX; 10 mg/kg) in mice resulted in an elevation of 49% in DNA synthesis of esophageal epithelial cells at 1600, but had no effect at 0630. Mice subjected to [Met5]enkephalin (1 mg/kg) had an LI that was decreased 23% from control levels at 0630, but was unaffected at 1600. This decrease in DNA synthesis was blocked by concomitant administration of naloxone (10 mg/kg); naloxone alone had no influence on cell replicative processes. In tissue culture studies, NTX and OGF markedly increased and decreased, respectively, the LI from control values. Both opioid growth factor (OGF) and its receptor, zeta, were detected in all but the cornified layer of mouse esophageal epithelium and in the epithelial cells of the stomach and small and large intestines. In addition, both peptide and receptor were observed in the basal and suprabasal cells of human esophageal epithelium. These results indicate that an endogenous opioid peptide (OGF) and its receptor (zeta) reside in gastrointestinal epithelium and play a role in cellular renewal processes in a tonically inhibitory, direct, and circadian rhythm-dependent fashion.

scholarly journals Gelatin Sheet Incorporating Basic Fibroblast Growth Factor Enhances Healing of Devascularized Sternum in Diabetic Rats

Circulation ◽  
2001 ◽  
Vol 104 (suppl_1) ◽  
Author(s):  
Atsushi Iwakura ◽  
Yasuhiko Tabata ◽  
Nobushige Tamura ◽  
Kazuhiko Doi ◽  
Kazunobu Nishimura ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Bone Mineral ◽  
Basic Fibroblast Growth Factor ◽  
Median Sternotomy ◽  
Diabetic Rats ◽  
Wound Complications ◽  
Diabetic Patients ◽  
Fibroblast Growth ◽  
Mineral Density

Background Poor healing of the sternum often limits the use of bilateral internal thoracic arteries (BITAs) after coronary bypass surgery in diabetic patients. We have reported that a gelatin sheet that incorporates basic fibroblast growth factor (bFGF) accelerates sternal healing after BITA removal in normal rats. This study evaluated the effects of the above method for sternal healing in diabetic animals. Methods and Results Diabetic Wistar rats with blood glucose levels >400 mg/dL and body-weight loss >20 g were established by a single intravenous injection of streptozotocin (55 mg/kg). After median sternotomy and BITA removal, 16 diabetic rats received either a gelatin sheet that incorporated bFGF (100 μg/sheet) on the posterior table of the sternum (FGF group, n=9) or no gelatin sheet (control, n=7). Peristernal blood flow, as measured by a noncontact laser Doppler 4 weeks after surgery in the FGF group, recovered to the preoperative level (106±10% versus 82±9%, P <0.01), and marked angiogenesis was also observed around the sternum in the FGF group (30.5±3.2 versus 15.8±2.7 vessels/unit area, P <0.01). Deep sternal wound complications developed in 5 control rats but only in 1 rat in the FGF group ( P <0.05). In the FGF group, histological examination showed improved sternal healing (excellent in 6 rats and slow/poor healing in 3). Bone mineral content as assessed by dual-energy x-ray absorptometry was greater in the FGF group (75.9±18.1 versus 48.9±10.7 mg, P <0.05). Bone mineral density of the sternum was similar between the 2 groups. Conclusions A gelatin sheet that incorporates bFGF may offset sternal ischemia and accelerate sternal bone regeneration and healing, even in diabetic patients.

scholarly journals Enhanced permeability responses to inflammation in streptozotocin-induced diabetic rat venules: Rho-mediated alterations of actin cytoskeleton and VE-cadherin

2014 ◽  
Vol 307 (1) ◽  
pp. H44-H53 ◽  
Author(s):  
Dong Yuan ◽  
Sulei Xu ◽  
Pingnian He
Keyword(s):  
Endothelial Cells ◽  
Microvascular Complications ◽  
Diabetic Rats ◽  
Fiber Formation ◽  
Receptor Expression ◽  
Diabetic Patients ◽  
No Production ◽  
Significant Difference ◽  
Microvessel Permeability ◽  
The Impact

Diabetes is a progressive disease that often leads to microvascular complications. This study investigates the impact of diabetes on microvessel permeability under basal and inflammatory conditions. Streptozotocin-induced diabetic rats were used to mimic type 1 diabetes. Parallel experiments were conducted in intact mesenteric venules in normal rats and diabetic rats experiencing hyperglycemia for 2–3 wk. Microvessel permeability was determined by measuring hydraulic conductivity (Lp). The correlated changes in endothelial intracellular Ca2+ concentration ([Ca2+]i), adherens junctions, and cytoskeleton F-actin were examined with fluorescence imaging. Diabetic vessels showed moderately increased basal Lp, but upon platelet-activating factor (PAF) exposure, these vessels showed an ∼10-fold higher Lp increase than the normal vessels. Concomitantly, we observed higher increases in endothelial [Ca2+]i, enhanced stress fiber formation, vascular endothelial-cadherin separation, and larger gap formation between endothelial cells than those occurring in normal vessels. PAF receptor staining showed no significant difference between normal and diabetic vessels. The application of Rho kinase inhibitor Y27632 did not affect PAF-induced increases in endothelial [Ca2+]i but significantly reduced PAF-induced Lp increases by 90% in diabetic vessels. The application of both Y27632 and nitric oxide (NO) synthase inhibitor attenuated PAF-induced Lp increases more than using one inhibitor alone. Our studies indicate that diabetic conditions prime endothelial cells into a phenotype with increased susceptibility to inflammation without altering receptor expression and that the increased Rho activation and NO production play important roles in exaggerated permeability increases when diabetic vessels were exposed to inflammatory mediators, which may account for the exacerbated vascular dysfunction when diabetic patients are exposed to additional inflammation.

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