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Bayir MH, Yıldızhan K, Altındağ F. Effect of Hesperidin on Sciatic Nerve Damage in STZ-Induced Diabetic Neuropathy: Modulation of TRPM2 Channel. Neurotox Res 2023; 41:638-647. [PMID: 37439953 DOI: 10.1007/s12640-023-00657-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 06/07/2023] [Accepted: 07/01/2023] [Indexed: 07/14/2023]
Abstract
Diabetic neuropathy (DNP) is a severe complication of diabetes mellitus. In this study, we examined the potential of hesperidin (HES) to attenuate DNP and the involvement of the TRPM2 channel in this process. The rats were given a single dose of 45 mg/kg of streptozotocin (STZ) intraperitoneally to induce diabetic neuropathic pain. On the third day, we confirmed the development of diabetes in the DNP and DNP + HES groups. The HES groups were treated with 100 mg/kg and intragastric gavage daily for 14 days. The results showed that treatment with HES in diabetic rats decreased STZ-induced hyperglycemia and thermal hyperalgesia. Furthermore, in the histopathological examination of the sciatic nerve, HES treatment reduced STZ-induced damage. The immunohistochemical analysis also determined that STZ-induced increased TRPM2 channel, type-4 collagen, and fibrinogen immunoactivity decreased with HES treatment. In addition, we investigated the TRPM2 channel activation in the sciatic nerve damage mechanism of DNP model rats created by STZ application using the ELISA method. We determined the regulatory effect of HES on increased ROS, and PARP1 and TRPM2 channel activation in the sciatic nerves of DNP model rats. These findings indicated that hesperidin treatment could attenuate diabetes-induced DNP by reducing TRPM2 channel activation.
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Affiliation(s)
- Mehmet Hafit Bayir
- Department of Histology and Embryology, Faculty of Medicine, Van Yuzuncu Yil University, Van, Turkey
| | - Kenan Yıldızhan
- Department of Biophysics, Faculty of Medicine, Van Yuzuncu Yil University, Van, Turkey.
| | - Fikret Altındağ
- Department of Histology and Embryology, Faculty of Medicine, Van Yuzuncu Yil University, Van, Turkey
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Colcimen N, Altindag F. Evaluation of the effects of sinapic acid and ellagic acid on sciatic nerve in experimental diabetic rats by immunohistochemical and stereological methods. J Chem Neuroanat 2023; 131:102274. [PMID: 37085061 DOI: 10.1016/j.jchemneu.2023.102274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
In our study, we aimed to examine the effects of sinapic acid and ellagic acid on neuropathy caused by diabetes in peripheral nerves. Fifty-six adult Wistar Albino rats Control, Diabetes, Diabetes+Sinapic Acid, Diabetes+Ellagic Acid, Diabetes+Sinapic Acid+Ellagic Acid, Sinapic Acid, Ellagic Acid and as Sinapic Acid+Ellagic Acid, they were randomly divided into eight groups(n:7). A single dose of 50 mg/kg streptozotocin(STZ) was administered intraperitoneally to the groups to be diagnosed with diabetes. Diabetes was accepted as blood glucose value of 250 mg/dL and above. Streptozotocin was given to the diabetes groups, 20 mg/kg/day intragastric Sinapic acid to the Sinapic acid groups, 50 mg/kg/day intragastric Ellagic acid to the Ellagic acid groups for 28 days. At the end of the experiment, 0.5 cm of the right sciatic nerve was removed. It was fixed in 10% formaldehyde. After histological follow-up, it was embedded in paraffin, 5 µm thick sections were taken. Immunohistochemical staining with Fibrinogen alpha, Laminin β-1 and Collagen IV antibodies and stereological evaluation was performed by Physical Dissector Combination method. Collagen IV was used in control, diabetes and treatment groups showed similar immunostaining. Fibrinogen alpha was observed to be increased in the vessel wall in the diabetes group, while the uptake was minimal in the control and treatment groups. While Laminin β-1 was increased in the diabetes group compared to the control group, immunostaining was observed in the treatment groups similar to the control group. It was observed that the total nerve area diabetes group decreased significantly compared to the control group, and the treatment groups, except for D+EA group were similar to the control group, but there was no statistically significant difference. The axon numbers in the diabetes group decreased significantly compared to the control group, and the treatment groups were similar to the control group, and there was no statistically significant difference (P > 0.05). It was determined that Sinapic Acid and Ellagic acid had positive effects on the nervous tissue in diabetic neuropathy.
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Affiliation(s)
- Nese Colcimen
- Department of Histology and Embryology, Medical School of Van Yuzuncu Yil University, Van, Turkey.
| | - Fikret Altindag
- Department of Histology and Embryology, Medical School of Van Yuzuncu Yil University, Van, Turkey
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Assessing Collagen D-Band Periodicity with Atomic Force Microscopy. MATERIALS 2022; 15:ma15041608. [PMID: 35208148 PMCID: PMC8877100 DOI: 10.3390/ma15041608] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/01/2023]
Abstract
The collagen superfamily includes more than fifty collagen and/or collagen-like proteins with fibril-forming collagen type I being the most abundant protein within the extracellular matrix. Collagen type I plays a crucial role in a variety of functions, it has been associated with many pathological conditions and it is widely used due to its unique properties. One unique nano-scale characteristic of natural occurring collagen type I fibers is the so-called D-band periodicity, which has been associated with collagen natural structure and properties, while it seems to play a crucial role in the interactions between cells and collagen and in various pathological conditions. An accurate characterization of the surface and structure of collagen fibers, including D-band periodicity, on collagen-based tissues and/or (nano-)biomaterials can be achieved by Atomic Force Microscopy (AFM). AFM is a scanning probe microscope and is among the few techniques that can assess D-band periodicity. This review covers issues related to collagen and collagen D-band periodicity and the use of AFM for studying them. Through a systematic search in databases (PubMed and Scopus) relevant articles were identified. The study of these articles demonstrated that AFM can offer novel information concerning D-band periodicity. This study highlights the importance of studying collagen D-band periodicity and proves that AFM is a powerful tool for investigating a number of different properties related to collagen D-band periodicity.
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Wieringa PA, Gonçalves de Pinho AR, Micera S, Wezel RJA, Moroni L. Biomimetic Architectures for Peripheral Nerve Repair: A Review of Biofabrication Strategies. Adv Healthc Mater 2018; 7:e1701164. [PMID: 29349931 DOI: 10.1002/adhm.201701164] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/13/2017] [Indexed: 12/19/2022]
Abstract
Biofabrication techniques have endeavored to improve the regeneration of the peripheral nervous system (PNS), but nothing has surpassed the performance of current clinical practices. However, these current approaches have intrinsic limitations that compromise patient care. The "gold standard" autograft provides the best outcomes but requires suitable donor material, while implantable hollow nerve guide conduits (NGCs) can only repair small nerve defects. This review places emphasis on approaches that create structural cues within a hollow NGC lumen in order to match or exceed the regenerative performance of the autograft. An overview of the PNS and nerve regeneration is provided. This is followed by an assessment of reported devices, divided into three major categories: isotropic hydrogel fillers, acting as unstructured interluminal support for regenerating nerves; fibrous interluminal fillers, presenting neurites with topographical guidance within the lumen; and patterned interluminal scaffolds, providing 3D support for nerve growth via structures that mimic native PNS tissue. Also presented is a critical framework to evaluate the impact of reported outcomes. While a universal and versatile nerve repair strategy remains elusive, outlined here is a roadmap of past, present, and emerging fabrication techniques to inform and motivate new developments in the field of peripheral nerve regeneration.
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Affiliation(s)
- Paul A. Wieringa
- Department of Complex Tissue RegenerationMERLN Institute for Technology‐Inspired Regenerative MedicineMaastricht University Universiteitssingel 40 Maastricht 6229 ER The Netherlands
| | - Ana Rita Gonçalves de Pinho
- Tissue Regeneration DepartmentMIRA InstituteUniversity of Twente Drienerlolaan 5 Enschede 7522 NB The Netherlands
| | - Silvestro Micera
- BioRobotics InstituteScuola Superiore Sant'Anna Viale Rinaldo Piaggio 34 Pontedera 56025 Italy
- Translational Neural Engineering LaboratoryEcole Polytechnique Federale de Lausanne Ch. des Mines 9 Geneva CH‐1202 Switzerland
| | - Richard J. A. Wezel
- BiophysicsDonders Institute for BrainCognition and BehaviourRadboud University Kapittelweg 29 Nijmegen 6525 EN The Netherlands
- Biomedical Signals and SystemsMIRA InstituteUniversity of Twente Drienerlolaan 5 Enschede 7522 NB The Netherlands
| | - Lorenzo Moroni
- Department of Complex Tissue RegenerationMERLN Institute for Technology‐Inspired Regenerative MedicineMaastricht University Universiteitssingel 40 Maastricht 6229 ER The Netherlands
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Lui PPY. Tendinopathy in diabetes mellitus patients-Epidemiology, pathogenesis, and management. Scand J Med Sci Sports 2017; 27:776-787. [PMID: 28106286 DOI: 10.1111/sms.12824] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2016] [Indexed: 12/15/2022]
Abstract
Chronic tendinopathy is a frequent and disabling musculo-skeletal problem affecting the athletic and general populations. The affected tendon is presented with local tenderness, swelling, and pain which restrict the activity of the individual. Tendon degeneration reduces the mechanical strength and predisposes it to rupture. The pathogenic mechanisms of chronic tendinopathy are not fully understood and several major non-mutually exclusive hypotheses including activation of the hypoxia-apoptosis-pro-inflammatory cytokines cascade, neurovascular ingrowth, increased production of neuromediators, and erroneous stem cell differentiation have been proposed. Many intrinsic and extrinsic risk/causative factors can predispose to the development of tendinopathy. Among them, diabetes mellitus is an important risk/causative factor. This review aims to appraise the current literature on the epidemiology and pathology of tendinopathy in diabetic patients. Systematic reviews were done to summarize the literature on (a) the association between diabetes mellitus and tendinopathy/tendon tears, (b) the pathological changes in tendon under diabetic or hyperglycemic conditions, and (c) the effects of diabetes mellitus or hyperglycemia on the outcomes of tendon healing. The potential mechanisms of diabetes mellitus in causing and exacerbating tendinopathy with reference to the major non-mutually exclusive hypotheses of the pathogenic mechanisms of chronic tendinopathy as reported in the literature are also discussed. Potential strategies for the management of tendinopathy in diabetic patients are presented.
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Affiliation(s)
- P P Y Lui
- Headquarter, Hospital Authority, Hong Kong SAR, China
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Ishibashi F, Taniguchi M, Kojima R, Kawasaki A, Kosaka A, Uetake H. Elasticity of the tibial nerve assessed by sonoelastography was reduced before the development of neuropathy and further deterioration associated with the severity of neuropathy in patients with type 2 diabetes. J Diabetes Investig 2015; 7:404-12. [PMID: 27330728 PMCID: PMC4847896 DOI: 10.1111/jdi.12408] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 06/27/2015] [Accepted: 07/29/2015] [Indexed: 12/23/2022] Open
Abstract
Aims/Introduction To measure the elasticity of the tibial nerve using sonoelastography, and to associate it with diabetic neuropathy severity, the cross‐sectional area of the tibial nerve and neurophysiological findings in type 2 diabetic patients. Materials and Methods The elasticity of the tibial nerve was measured as the tibial nerve:acoustic coupler strain ratio using high‐resolution ultrasonography in 198 type 2 diabetic patients stratified into subgroups by neuropathy severity, and 29 control participants whose age and sex did not differ from the diabetic subgroups. Results The elasticity of the tibial nerve in patients without neuropathy (P < 0.001) was reduced compared with controls (0.76 ± 0.023), further decreasing (0.655 ± 0.014 to 0.414 ± 0.018) after developing neuropathy. The cut‐off value of elasticity of the tibial nerve that suggested the presence of neuropathy was 0.558. The area under the curve (0.829) was greater than that for the cross‐sectional area (0.612). The cross‐sectional area of the tibial nerve in diabetic patients without neuropathy (6.11 ± 0.13 mm2) was larger than that in controls (4.84 ± 0.16 mm2), and increased relative to neuropathy severity (P < 0.0001). The elasticity of the tibial nerve was negatively associated with neuropathy severity (P < 0.0001), cross‐sectional area (P = 0.002) and 2000 Hz current perception threshold (P = 0.011), and positively associated with nerve conduction velocities (P < 0.0001). Conclusions Determining the elasticity of the tibial nerve in type 2 diabetic patients could reveal early biomechanical changes that were likely caused by thickened fibrous sheaths of peripheral nerves, and might be a novel tool for characterizing diabetic neuropathy.
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Internal-specific morphological analysis of sciatic nerve fibers in a radiofrequency-induced animal neuropathic pain model. PLoS One 2013; 8:e73913. [PMID: 24066083 PMCID: PMC3774755 DOI: 10.1371/journal.pone.0073913] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/23/2013] [Indexed: 12/27/2022] Open
Abstract
This study investigated the reversible effects of pulsed radiofrequency (PRF) treatment at 42 °C on the ultrastructural and biological changes in nerve and collagen fibers in the progression of neuropathic pain after rat sciatic nerve injury. Assessments of morphological changes in the extracellular matrices by atomic force microscopy and hematoxylin-eosin, Masson's trichrome and picrosirius-red staining as well as the expressions of two fibril-forming collagens, types-I and -III, and two inflammatory cytokines, TNF-α and IL-6, were evaluated on day 30 after RF exposure. There were four groups for different RF thermal treatments: no treatment, no current, PRF, and continuous RF (CRF). An RF procedure similar to that used in human clinical trials was used in this study. The CRF treatment at 82 °C led to neural and collagen damage by the permanent blockage of sensory nociceptors. The PRF treatment led to excellent performance and high expandability compared to CRF, with effects including slight damage and swelling of myelinated axons, a slightly decreased amount of collagen fibers, swelling of collagen fibril diameters, decreased immunoreactivity of collagen types-I and -III, presence of newly synthesized collagen, and recovery of inflammatory protein immunoreactivity. These evidence-based findings suggest that PRF-based pain relief is responsible for the temporary blockage of nerve signals as well as the preferential destruction of pain-related principal sensory fibers like the Aδ and C fibers. This suggestion can be supported by the interaction between the PRF-induced electromagnetic field and cell membranes; therefore, PRF treatment provides pain relief while allowing retention of some tactile sensation.
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Choi S, Choi H, Cheong Y, Chung S, Park H, Lim Y. Inflammatory responses and morphological changes of radiofrequency-induced rat sciatic nerve fibres. Eur J Pain 2013; 18:192-203. [DOI: 10.1002/j.1532-2149.2013.00391.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2013] [Indexed: 01/27/2023]
Affiliation(s)
- S. Choi
- Department of Biomedical Engineering & Healthcare Industry Research Institute; Kyung Hee University; Seoul Korea
| | - H.J. Choi
- Department of Neurosurgery; Kyung Hee University; Seoul Korea
| | - Y. Cheong
- Department of Biomedical Engineering & Healthcare Industry Research Institute; Kyung Hee University; Seoul Korea
| | - S.H. Chung
- Department of Pharmacology and Clinical Pharmacy & Life and Nanopharmaceutical Science; Kyung Hee University; Seoul Korea
| | - H.K. Park
- Department of Biomedical Engineering & Healthcare Industry Research Institute; Kyung Hee University; Seoul Korea
- Department of Medical Engineering; Kyung Hee University; Seoul Korea
| | - Y.J. Lim
- Department of Neurosurgery; Kyung Hee University; Seoul Korea
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Denning D, Alilat S, Habelitz S, Fertala A, Rodriguez BJ. Visualizing molecular polar order in tissues via electromechanical coupling. J Struct Biol 2012; 180:409-19. [PMID: 22985991 PMCID: PMC4409004 DOI: 10.1016/j.jsb.2012.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 08/16/2012] [Accepted: 09/06/2012] [Indexed: 10/27/2022]
Abstract
Electron microscopy (EM) and atomic force microscopy (AFM) techniques have long been used to characterize collagen fibril ordering and alignment in connective tissues. These techniques, however, are unable to map collagen fibril polarity, i.e., the polar orientation that is directed from the amine to the carboxyl termini. Using a voltage modulated AFM-based technique called piezoresponse force microscopy (PFM), we show it is possible to visualize both the alignment of collagen fibrils within a tissue and the polar orientation of the fibrils with minimal sample preparation. We demonstrate the technique on rat tail tendon and porcine eye tissues in ambient conditions. In each sample, fibrils are arranged into domains whereby neighboring domains exhibit opposite polarizations, which in some cases extend to the individual fibrillar level. Uniform polarity has not been observed in any of the tissues studied. Evidence of anti-parallel ordering of the amine to carboxyl polarity in bundles of fibrils or in individual fibrils is found in all tissues, which has relevance for understanding mechanical and biofunctional properties and the formation of connective tissues. The technique can be applied to any biological material containing piezoelectric biopolymers or polysaccharides.
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Affiliation(s)
- Denise Denning
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sofiane Alilat
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stefan Habelitz
- Department of Preventive and Restorative Dental Sciences, University of California, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA
| | - Andrzej Fertala
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA
| | - Brian J. Rodriguez
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
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The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus. Clin Biomech (Bristol, Avon) 2012; 27:967-71. [PMID: 22809735 PMCID: PMC3772678 DOI: 10.1016/j.clinbiomech.2012.06.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 06/27/2012] [Accepted: 06/28/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND The peripheral nervous system has an inherent capability to tolerate the gliding (excursion), stretching (increased strain), and compression associated with limb motions necessary for functional activities. The biomechanical properties during joint movements are well studied but the influence of other factors such as limb pre-positioning, age and the effects of diabetes mellitus are not well established for the lower extremity. The purposes of this pilot study were to compare the impact of two different hip positions on lower extremity nerve biomechanics during an active ankle dorsiflexion motion in healthy individuals and to determine whether nerve biomechanics are altered in older individuals with diabetes mellitus. METHODS Ultrasound imaging was used to quantify longitudinal motion of the tibial nerve and transverse plane motion of the tibial and common fibular nerves in the popliteal fossa during active ankle movements. FINDINGS In healthy individuals, ankle dorsiflexion created mean tibial nerve movement of 2.18 mm distally, 1.36 mm medially and 3.98 mm superficially. When the hip was in a flexed position there was a mean three-fold reduction in distal movement. In people with diabetes mellitus there was significantly less distal movement of the tibial nerve in the neutral hip position and less superficial movement of the nerve in both hip positions compared to healthy individuals. INTERPRETATION We have documented reductions in tibial nerve excursion due to limb pre-positioning thought to pre-load the nervous system using a non-invasive methodology. Thus, lower limb pre-positioning impacts nerve biomechanics during ankle motions common in functional activities. Additionally, our findings indicate that nerve biomechanics have the potential to be altered in older individuals with diabetes mellitus compared to younger healthy individuals.
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Anigbogu CN, Speakman RO, Silcox DL, Brown LV, Brown DR, Gong MC, Patwardhan AR, Reynolds LR, Karounos DG, Burgess DE, Baldridge BR, Randall DC. Extended longitudinal analysis of arterial pressure and heart rate control in unanesthetized rats with type 1 diabetes. Auton Neurosci 2012; 170:20-9. [PMID: 22809731 DOI: 10.1016/j.autneu.2012.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/20/2012] [Accepted: 06/21/2012] [Indexed: 11/15/2022]
Abstract
We recorded arterial pressure (BP) and heart rate (HR) in type-1 diabetic rats vs. controls for >6 months. Diabetic rats (DIAB) were maintained on insulin from the day glucose >250 mg/dl ("Day 0"). Weight was similar between groups until ~3 weeks before Day 0 when the weight in DIAB transiently lagged the controls (CONT); this difference was maintained throughout the study, but both groups otherwise gained weight in parallel. Plasma glucose attained 371 ± 109 (SD) mg/dl by day 1 in DIAB. Mean BP was similar across groups, and declined through the initial 4-6 months in both the CONT (at -0.06 ± 0.04 mmHg/day) and in the DIAB (at -0.14 ± 0.21 mmHg/day; NS vs. CONT). HR in the CONT (Month 1: 341 ± 13 bpm) exceeded DIAB (325 ± 25 bpm) through ~6 months after Day 0, and also decreased progressively over this period in CONT (-0.19 ± 0.14 bpm/day) and DIAB (-0.29 ± 0.23 bpm/day; NS vs. CONT) before leveling. The BP power within 0.35-0.45 Hz changed during the 90 min before vs. after the transition from dark to light, and light to dark; there were no between group differences. The slope of the log-log linear portion of the BP power spectrum between 1.0/h and 1/min was similar across groups, and increased in both from month 1 to month 6. Regulatory mechanisms maintain similar profiles in BP and HR in diabetic vs. control animals through the initial half year of the disease.
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Affiliation(s)
- Chikodi N Anigbogu
- Department of Physiology, College of Medicine, University of Lagos, Idi-Araba, Nigeria
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Abstract
This chapter describes methods for isolating and imaging metabolically and toxicologically challenged mitochondria with atomic force microscopy. Mitochondria were isolated from rat dorsal root ganglia or brain and exposed to glucose or dinitrobenzene (DNB) to simulate the cellular environment of a diabetic animal that has been exposed to excess glucose or to DNB. It is one of only a few articles to present images of membrane structures, such as voltage-dependent, anion-selective channel pores, on intact organelles. The purpose of the chapter is not to report on the metabolic or toxic effects, but to communicate in more detail than a typical journal paper allows the methods used to image isolated organelles. We also provide a series images revealing the outer membrane and outer membrane pores. An image of an isolated nucleus as well as a set of notes written to avoid common pitfalls in isolation, labeling, and imaging is also included.
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Affiliation(s)
- Bradley E Layton
- Applied Computing and Electronics, The University of Montana College of Technology, Missoula, MT, USA.
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Randall DC, Speakman RO, Silcox DL, Brown LV, Brown DR, Gong MC, Patwardhan A, Reynolds LR, Karounos DG, Burgess DE, Anigbogu CN. Longitudinal analysis of arterial blood pressure and heart rate response to acute behavioral stress in rats with type 1 diabetes mellitus and in age-matched controls. Front Physiol 2011; 2:53. [PMID: 21904530 PMCID: PMC3163305 DOI: 10.3389/fphys.2011.00053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 08/09/2011] [Indexed: 11/13/2022] Open
Abstract
We recorded via telemetry the arterial blood pressure (BP) and heart rate (HR) response to classical conditioning following the spontaneous onset of autoimmune diabetes in BBDP/Wor rats vs. age-matched, diabetes-resistant control (BBDR/Wor) rats. Our purpose was to evaluate the autonomic regulatory responses to an acute stress in a diabetic state of up to 12 months duration. The stress was a 15-s pulsed tone (CS+) followed by a 0.5-s tail shock. The initial, transient increase in BP (i.e., the "first component," or C(1)), known to be derived from an orienting response and produced by a sympathetic increase in peripheral resistance, was similar in diabetic and control rats through ∼9 months of diabetes; it was smaller in diabetic rats 10 months after diabetes onset. Weakening of the C(1) BP increase in rats that were diabetic for >10 months is consistent with the effects of sympathetic neuropathy. A longer-latency, smaller, but sustained "second component" (C(2)) conditional increase in BP, that is acquired as a rat learns the association between CS+ and the shock, and which results from an increase in cardiac output, was smaller in the diabetic vs. control rats starting from the first month of diabetes. A concomitant HR slowing was also smaller in diabetic rats. The difference in the C(2) BP increase, as observed already during the first month of diabetes, is probably secondary to the effects of hyperglycemia upon myocardial metabolism and contractile function, but it may also result from effects on cognition. The small HR slowing concomitant with the C(2) pressor event is probably secondary to differences in baroreflex activation or function, though parasympathetic dysfunction may contribute later in the duration of diabetes. The nearly immediate deficit after disease onset in the C(2) response indicates that diabetes alters BP and HR responses to external challenges prior to the development of structural changes in the vasculature or autonomic nerves.
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Affiliation(s)
- David C Randall
- Department of Physiology, University of Kentucky College of Medicine Lexington, KY, USA
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Enabling tools for engineering collagenous tissues integrating bioreactors, intravital imaging, and biomechanical modeling. Proc Natl Acad Sci U S A 2009; 107:3335-9. [PMID: 19955446 DOI: 10.1073/pnas.0907813106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many investigators have engineered diverse connective tissues having good mechanical properties, yet few tools enable a global understanding of the associated formation of collagen fibers, the primary determinant of connective tissue stiffness. Toward this end, we developed a biomechanical model for collagenous tissues grown on polymer scaffolds that accounts for the kinetics of polymer degradation as well as the synthesis and degradation of multiple families of collagen fibers in response to cyclic strains imparted in a bioreactor. The model predicted well both overall thickness and stress-stretch relationships for tubular engineered vessels cultured for 8 weeks, and suggested that a steady state had not yet been reached. To facilitate future refinements of the model, we also developed bioreactors that enable intravital nonlinear optical microscopic imaging. Using these tools, we found that collagen fiber alignment was driven strongly by nondegraded polymer fibers at early times during culture, with subsequent mechano-stimulated dispersal of fiber orientations as polymer fibers degraded. In summary, mathematical models of growth and remodeling of engineered tissues cultured on polymeric scaffolds can predict evolving tissue morphology and mechanics after long periods of culture, and related empirical observations promise to further our understanding of collagen matrix development in vitro.
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Layton BE, Gupta R, Jackson NL, Shah AJ, Stallcup RE, Sullivan SM. Nanomanipulation and characterization of structural proteins. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:2582-3. [PMID: 17270802 DOI: 10.1109/iembs.2004.1403742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A methodology is presented for simultaneous mechanical testing and atomic force microscopy imaging of single collagen fibrils under load. This method holds the promise for determining single-fibril modulus and strength in various experimental preparations. Examples of this utility include characterization of deformation and failure modes of naturally occurring and engineered structural proteins. Additional promise of this technique is robotic surgery at the submicron scale for repairing neuronal tracts and capillaries with structural proteins. A series of algorithms for tying knots at the nanoscale in single fibrils is also presented.
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Affiliation(s)
- B E Layton
- Dept. of Mech. Eng. & Mech., Drexel Univ., Philadelphia, PA, USA
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Layton BE, Sastry AM. Equal and local-load-sharing micromechanical models for collagens: quantitative comparisons in response of non-diabetic and diabetic rat tissue. Acta Biomater 2006; 2:595-607. [PMID: 16905373 DOI: 10.1016/j.actbio.2006.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 05/09/2006] [Accepted: 05/17/2006] [Indexed: 12/14/2022]
Abstract
Chemical crosslinks in collagens resulting from binding of advanced glycation end-products, have long been presumed to alter the stiffness and permeability of glycated tissues. Recently, we developed a stochastic mechanical model for the response and failure of uniaxially deformed sciatic nerve tissue from diabetic and control rats. Here, we use our model to determine the likely correlation of fibril glycation with failure response, by quantifying statistical differences in their response. Our four-parameter model describes both the non-linear toe region and non-linear failure region of these tissues; the four parameters consist of (1) collagen fibril alignment, (2) fiber bundle waviness, (3) Weibull shape parameter for fibrillar strength, and (4) modulus-normalized Weibull scale parameter for fibrillar strength. Using an equal load sharing model we find that diabetic and control tissues had shape parameters of 9.88+/-5.50 and 4.33+/-3.67 (p=0.043), respectively, and scale parameters of 0.28+/-0.07 and 0.58+/-0.25 (p=0.033), respectively, implying that the diabetic tissue behaves in a more brittle manner, consistent with more highly crosslinked fibrils. We conclude that biochemical crosslinking directly affects measured mechanical properties. Further, this mechanical characterization may prove useful in mapping alterations in stiffness and permeability observed in glycated tissues.
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Affiliation(s)
- Bradley E Layton
- Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA
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Layton BE, Sastry AM. A mechanical model for collagen fibril load sharing in peripheral nerve of diabetic and nondiabetic rats. J Biomech Eng 2005; 126:803-14. [PMID: 15796339 DOI: 10.1115/1.1824118] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Peripheral neuropathy affects approximately 50% of the 15 million Americans with diabetes. It has been suggested that mechanical effects related to collagen glycation are related to the permanence of neuropathy. In the present paper, we develop a model for load transfer in a whole nerve, using a simple pressure vessel approximation, in order to assess the significant of stiffening of the collagenous nerve sheath on endoneurial fluid pressure. We also develop a fibril-scale mechanics model for the nerve, to model the straightening of wavy fibrils, producing the toe region observed in nerve tissue, and also to interrogate the effects of interfibrillar crosslinks on the overall properties of the tissue. Such collagen crosslinking has been implicated in complications in diabetic tissues. Our fibril-scale model uses a two-parameter Weibull model for fibril strength, in combination with statistical parameters describing fibril modulus, angle, wave-amplitude, and volume fraction to capture both toe region and failure region behavior of whole rat sciatic nerve. The extrema of equal and local load-sharing assumptions are used to map potential differences in diabetic and nondiabetic tissues. This work may ultimately be useful in differentiating between the responses of normal and heavily crosslinked tissue.
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Affiliation(s)
- B E Layton
- Department of Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125, USA
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Layton BE, Sastry AM, Wang H, Sullivan KA, Feldman EL, Komorowski TE, Philbert MA. Differences between collagen morphologies, properties and distribution in diabetic and normal biobreeding and Sprague–Dawley rat sciatic nerves. J Biomech 2004; 37:879-88. [PMID: 15111075 DOI: 10.1016/j.jbiomech.2003.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2003] [Indexed: 11/23/2022]
Abstract
Both structural and functional differences between normal and diabetic nerve have been observed, in human patients and animal models. We hypothesize that these structural differences are quantifiable, morphologically and mechanically, with the ultimate aim of understanding the contribution of these differences to permanent nerve damage. The outer collagenous epineurial and perineurial tissues of mammalian peripheral nerves mechanically and chemically shield the conducting axons. We have quantified differences in these collagens, using whole-nerve uniaxial testing, and immunohistochemistry of collagens type I, III, and IV in diabetic and normal nerves. We present results of two studies, on normal and diabetic BioBreeding (BB), and normal, diabetic and weight-controlled Sprague-Dawley (SD) rats, respectively. Overall, we measured slightly higher uniaxial moduli (e.g. 5.9 MPa vs. 3.5 MPa, BB; 10.7 MPa vs. 10.0 MPa, SD at 40% strain) in whole nerves as well as higher peak stresses (e.g. 0.99 MPa vs. 0.74 MPa, BB; 2.16 MPa vs. 1.94 MPa, SD at 40% strain) in the diabetics of both animal models. We measured increased concentrations of types III and IV collagens in the diabetics of both models and mixed upregulation results were observed in type I protein levels. We detected small differences in mechanical properties at the tissue scale, though we found significant structural and morphometric differences at the fibril scale. These findings suggest that whole-tissue mechanical testing is not a sufficient assay for collagen glycation, and that fibrillar and molecular scale assays are needed to detect the earliest stages of diabetic protein glycation.
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Affiliation(s)
- B E Layton
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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