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Tinasi ALSN, Silveira CPB, Honsho CS, Laus JL, Aldrovani M. Birefringence analysis of collagen supraorganization in cat corneas with tropical keratopathy. Vet Ophthalmol 2023; 26:398-406. [PMID: 37335898 DOI: 10.1111/vop.13124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/02/2023] [Accepted: 06/10/2023] [Indexed: 06/21/2023]
Abstract
OBJECTIVE To evaluate the birefringent properties of the cornea and examine the supraorganizational aspects of collagen fibers in cats with tropical keratopathy. PROCEDURE In this study, 10-micrometer-thick sections of corneal tissue from cats with tropical keratopathy were examined, both in the opaque and transparent areas of the anterior stroma. Control samples were obtained from healthy cat corneas. Polarized light microscopy was employed to evaluate the birefringent properties using two distinct methods. The first method involved measuring the optical retardation associated with corneal birefringence, while the second method assessed the alignment/waviness of the birefringent collagen fibers. Differences were significant when p < .05. RESULTS Tropical keratopathy resulted in a significant rise (p < .05) in optical retardation in both opaque and transparent regions of the cat cornea. In the anterior stroma, both the opaque zones and transparent tissue exhibited a higher degree of collagen fiber packing than the control corneas. However, no significant differences (p > .05) in alignment were observed between the transparent tissue of the diseased cornea and the healthy corneas. CONCLUSION Supraorganizational changes in collagen fiber packing are not restricted to lesion zones in cat corneas affected by tropical keratopathy. Such alterations also occur in the corneal tissue of the anterior stroma adjoining the lesions. Therefore, it is plausible that the transparent tissue of the anterior stroma in corneas affected by the disease may have functional abnormalities, despite its macroscopic healthy appearance. Additional investigations are required to clarify the implications of these potential defects and their conceivable contribution to tropical keratopathy.
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High-Performance Polarization Microscopy Reveals Structural Remodeling in Rat Calcaneal Tendons Cultivated In Vitro. Cells 2023; 12:cells12040566. [PMID: 36831234 PMCID: PMC9953949 DOI: 10.3390/cells12040566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/01/2023] [Accepted: 01/04/2023] [Indexed: 02/12/2023] Open
Abstract
Collagenous tissues exhibit anisotropic optical properties such as birefringence and linear dichroism (LD) as a result of their structurally oriented supraorganization from the nanometer level to the collagen bundle scale. Changes in macromolecular order and in aggregational states can be evaluated in tendon collagen bundles using polarization microscopy. Because there are no reports on the status of the macromolecular organization in tendon explants, the objective of this work was to evaluate the birefringence and LD characteristics of collagen bundles in rat calcaneal tendons cultivated in vitro on substrates that differ in their mechanical stiffness (plastic vs. glass) while accompanying the expected occurrence of cell migration from these structures. Tendon explants from adult male Wistar rats were cultivated for 8 and 12 days on borosilicate glass coverslips (n = 3) and on nonpyrogenic polystyrene plastic dishes (n = 4) and were compared with tendons not cultivated in vitro (n = 3). Birefringence was investigated in unstained tendon sections using high-performance polarization microscopy and image analysis. LD was studied under polarized light in tendon sections stained with the dichroic dyes Ponceau SS and toluidine blue at pH 4.0 to evaluate the orientation of proteins and acid glycosaminoglycans (GAG) macromolecules, respectively. Structural remodeling characterized by the reduction in the macromolecular orientation, aggregation and alignment of collagen bundles, based on decreased average gray values concerned with birefringence intensity, LD and morphological changes, was detected especially in the tendon explants cultivated on the plastic substrate. These changes may have facilitated cell migration from the lateral regions of the explants to the substrates, an event that was observed earlier and more intensely upon tissue cultivation on the plastic substrate. The axial alignment of the migrating cells relative to the explant, which occurred with increased cultivation times, may be due to the mechanosensitive nature of the tenocytes. Collagen fibers possibly played a role as a signal source to cells, a hypothesis that requires further investigation, including studies on the dynamics of cell membrane receptors and cytoskeletal organization, and collagen shearing electrical properties.
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Aldrovani M, Pereira AG, Tinasi ALSN, Brito VJDSC, Raposo ACS, Honsho CDS, Oriá AP. Birefringence Analyses Reveal Differences in Supramolecular Characteristics of Corneal Stromal Collagen Fibrils Between Falconiformes and Strigiformes. Integr Comp Biol 2021; 62:124-138. [PMID: 34313760 DOI: 10.1093/icb/icab171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study aimed to assess the birefringent properties of corneal stromal collagen fibrils in birds of the orders Falconiformes (diurnal) and Strigiformes (predominantly nocturnal) to compare their supramolecular organizations. Twenty-two corneas of Falconiformes (Caracara plancus, n = 8; Rupornis magnirostris, n = 10; and Falco sparverius, n = 4) and 28 of Strigiformes (Tyto furcata, n = 16; Pseudoscops clamator, n = 6; and Athene cunicularia, n = 6) were processed histotechnically into 8 μm thick sections. Corneal optical retardation values related to the form and intrinsic fractions of the total birefringence of collagen fibrils were measured using a polarized light microscope equipped with phase compensators. In addition, the coherence coefficients that inform the local orientation of the fibrils were calculated through video image analysis. All assessments were conducted both in the anterior and posterior stroma of the cornea. Differences were significant when p < 0.05. The results showed supraorganizational differences between fibrils in the anterior stroma of Falconiformes and Strigiformes. The optical retardation values were greater (p < 0.0001) for Falconiformes, indicating that the corneas of these birds contain more collagen fibrils or more aggregated collagen fibrils. In contrast, the coherence coefficients were higher (p = 0.016) for Strigiformes, indicating that the collagen fibers in these birds are highly aligned and have few undulations. A multivariate data matrix constructed for Euclidean distance calculations showed that the dissimilarity between Falconiformes and Strigiformes corneas, in terms of the supraorganization of stromal collagen fibrils, was 4.56%. In conclusion, it is possible that the supraorganizational differences reported in this study may be sources of variation in the visual quality of Falconiformes and Strigiformes. This study provides the necessary evidence to encourage further research associating corneal optical performance to supramolecular characteristics of corneal stromal collagen.
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Affiliation(s)
- Marcela Aldrovani
- Post-Graduation Program in Animal Science, Franca University, Franca, Brazil
| | | | | | | | | | | | - Arianne Pontes Oriá
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, Salvador, Brazil
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Effects and parameters of the photobiomodulation in experimental models of third-degree burn: systematic review. Lasers Med Sci 2018; 34:637-648. [DOI: 10.1007/s10103-018-2633-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 09/03/2018] [Indexed: 12/30/2022]
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Brassolatti P, de Andrade ALM, Bossini PS, Otterço AN, Parizotto NA. Evaluation of the low-level laser therapy application parameters for skin burn treatment in experimental model: a systematic review. Lasers Med Sci 2018; 33:1159-1169. [DOI: 10.1007/s10103-018-2526-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 04/25/2018] [Indexed: 12/18/2022]
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Chang CM, Lo YL, Tran NK, Chang YJ. Optical characterization of porcine articular cartilage using a polarimetry technique with differential Mueller matrix formulism. APPLIED OPTICS 2018; 57:2121-2127. [PMID: 29604002 DOI: 10.1364/ao.57.002121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A method is proposed for characterizing the optical properties of articular cartilage sliced from a pig's thighbone using a Stokes-Mueller polarimetry technique. The principal axis angle, phase retardance, optical rotation angle, circular diattenuation, diattenuation axis angle, linear diattenuation, and depolarization index properties of the cartilage sample are all decoupled in the proposed analytical model. Consequently, the accuracy and robustness of the extracted results are improved. The glucose concentration, collagen distribution, and scattering properties of samples from various depths of the articular cartilage are systematically explored via an inspection of the related parameters. The results show that the glucose concentration and scattering effect are both enhanced in the superficial region of the cartilage. By contrast, the collagen density increases with an increasing sample depth.
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The effect of polarized light on the organization of collagen secreted by fibroblasts. Lasers Med Sci 2017; 33:539-547. [DOI: 10.1007/s10103-017-2398-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
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Valdetaro GP, Aldrovani M, Padua IRM, Cristovam PC, Gomes JAP, Laus JL. Supra-organization and optical anisotropies of the extracellular matrix in the amniotic membrane and limbal stroma before and after explant culture. BIOMEDICAL OPTICS EXPRESS 2016; 7:4982-4994. [PMID: 28018719 PMCID: PMC5175546 DOI: 10.1364/boe.7.004982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/08/2016] [Accepted: 08/10/2016] [Indexed: 05/13/2023]
Abstract
In this research we evaluated the supramolecular organizations and the optical anisotropical properties of the de-epithelialized human amniotic membrane and rabbit limbal stroma, before and after explant culture. Birefringence, monochromatic light spectral absorption and linear dichroism of the main extracellular matrix biopolymers, that is, the fibrillar collagens and proteoglycans, were investigated by polarized light microscopy combined with image analysis. Our results demonstrated that the culture procedure-induced stimuli altered the supra-organizational characteristics (in terms of collagens/proteoglycans spatial orientation and ordered-aggregational state) of the amniotic and limbal extracellular matrix, which led to changes in optical anisotropical properties.
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Affiliation(s)
- Gisele P. Valdetaro
- Ophthalmology Unit, Department of Small Animal Medicine and Surgery, Faculty of Agrarian and Veterinary Sciences, UNESP Jaboticabal, 14884-900, SP, Brazil
| | - Marcela Aldrovani
- Ophthalmology Unit, Department of Small Animal Medicine and Surgery, Faculty of Agrarian and Veterinary Sciences, UNESP Jaboticabal, 14884-900, SP, Brazil
| | - Ivan R. M. Padua
- Ophthalmology Unit, Department of Small Animal Medicine and Surgery, Faculty of Agrarian and Veterinary Sciences, UNESP Jaboticabal, 14884-900, SP, Brazil
| | - Priscila C. Cristovam
- Ocular Surface Advanced Center, Federal University of São Paulo, UNIFESP São Paulo, 04039-002, SP, Brazil
| | - José A. P. Gomes
- Ocular Surface Advanced Center, Federal University of São Paulo, UNIFESP São Paulo, 04039-002, SP, Brazil
| | - José L. Laus
- Ophthalmology Unit, Department of Small Animal Medicine and Surgery, Faculty of Agrarian and Veterinary Sciences, UNESP Jaboticabal, 14884-900, SP, Brazil
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9
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Ahmad I, Ahmad M, Khan K, Ikram M. Polarimetry based partial least square classification of ex vivo healthy and basal cell carcinoma human skin tissues. Photodiagnosis Photodyn Ther 2016; 14:134-41. [DOI: 10.1016/j.pdpdt.2016.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 03/16/2016] [Accepted: 04/10/2016] [Indexed: 10/21/2022]
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de Loura Santana C, de Fátima Teixeira Silva D, Deana AM, Prates RA, Souza AP, Gomes MT, de Azevedo Sampaio BP, Shibuya JF, Bussadori SK, Mesquita-Ferrari RA, Fernandes KPS, França CM. Tissue responses to postoperative laser therapy in diabetic rats submitted to excisional wounds. PLoS One 2015; 10:e0122042. [PMID: 25909480 PMCID: PMC4409316 DOI: 10.1371/journal.pone.0122042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/05/2015] [Indexed: 01/09/2023] Open
Abstract
In a previous study about low-level laser therapy biomodulation on a full-thickness burn model we showed that single and fractionated dose regimens increased wound healing and leukocyte influx similarly when compared with untreated control. In order to verify if this finding would be similar in an impaired wound model, we investigated the effect of single and multiple irradiations on wound closure rate, type of inflammatory infiltrate, myofibroblasts, collagen deposition, and optical retardation of collagen in diabetic rats. Female Wistar rats in the same estrous cycle had diabetes induced with streptozotocin and an 8-mm excisional wound performed with a punch. The experimental groups were: control group--untreated ulcer; single-dose group--ulcer submitted to single dose of diode laser therapy (λ = 660 ± 2 nm; P = 30 mW; energy density: 4 J/cm2) and fractionated-dose group--ulcer submitted to 1 J/cm2 laser therapy on Days 1, 3, 8, and 10. The ulcers were photographed on the experimental days and after euthanasia tissue samples were routinely processed for histological and immunohistochemistry analyses. Independently of the energy density, laser therapy accelerated wound closure by approximately 40% in the first three days in comparison to the control group. Laser therapy increased acute inflammatory infiltrate until Day 3. Both laser groups exhibited more myofibroblasts and better collagen organization than the control group. The findings demonstrate that low-level laser therapy in the immediate postoperative period can enhance the tissue repair process in a diabetes model. Similar effects were achieved with laser therapy applied a single time with an energy density of 4 J/cm2 and applied four times with an energy density of 1 J/cm2. The application of laser therapy in the inflammatory phase was the most important factor to the enhancement of the tissue repair process.
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Affiliation(s)
- Cristiano de Loura Santana
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Daniela de Fátima Teixeira Silva
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Alessandro Melo Deana
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Renato Araujo Prates
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Amanda Pires Souza
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Mariana Teixeira Gomes
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | | | - Josiane Ferraretto Shibuya
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Sandra Kalil Bussadori
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | - Raquel Agnelli Mesquita-Ferrari
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
| | | | - Cristiane Miranda França
- Postgraduate Program in Biophotonics Applied to Health Sciences, University Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil
- * E-mail:
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11
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Objective assessment of endogenous collagen in vivo during tissue repair by laser induced fluorescence. PLoS One 2014; 9:e98609. [PMID: 24874229 PMCID: PMC4038633 DOI: 10.1371/journal.pone.0098609] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 05/06/2014] [Indexed: 01/31/2023] Open
Abstract
Collagen, a triple helical protein with the primary role of mechanical function, provides tensile strength to the skin, and plays a pivotal task in tissue repair. During tissue regeneration, collagen level increases gradually and therefore, monitoring of such changes in vivo by laser induced fluorescence was the main objective behind the present study. In order to accomplish this, 15 mm diameter excisional wounds were created on six to eight week old Swiss albino mice. The collagen deposition accelerated upon irradiation of single exposure of 2 J/cm2 He-Ne laser dose immediately after wounding was recorded by laser induced autofluorescence in vivo along with un-illuminated and un-wounded controls. Autofluorescence spectra were recorded for each animal of the experimental groups on 0, 5, 10, 30, 45 and 60 days post-wounding, by exciting the granulation tissue/skin with 325 nm He-Cd laser. The variations in the average collagen intensities from the granulation tissue/skin of mice were inspected as a function of age and gender. Further, the spectral findings of the collagen synthesis in wound granulation tissue/un-wounded skin tissues were validated by Picro-Sirius red- polarized light microscopy in a blinded manner through image analysis of the respective collagen birefringence. The in vivo autofluorescence studies have shown a significant increase in collagen synthesis in laser treated animals as compared to the un-illuminated controls. Image analysis of the collagen birefringence further authenticated the ability of autofluorescence in the objective monitoring of collagen in vivo. Our results clearly demonstrate the potential of laser induced autofluorescence in the monitoring of collegen synthesis during tissue regeneration, which may have clinical implications.
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Ando T, Sato S, Kobayashi H, Nawashiro H, Ashida H, Hamblin MR, Obara M. Low-level laser therapy for spinal cord injury in rats: effects of polarization. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:098002. [PMID: 24030687 PMCID: PMC3771552 DOI: 10.1117/1.jbo.18.9.098002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/11/2013] [Accepted: 08/07/2013] [Indexed: 05/30/2023]
Abstract
The effects of laser polarization on the efficacy of near-infrared low-level laser therapy for spinal cord injury (SCI) are presented. Rat spinal cords were injured with a weight-drop device, and the lesion sites were directly irradiated with a linearly polarized 808-nm diode laser positioned either perpendicular or parallel to the spine immediately after the injury and daily for five consecutive days. Functional recovery was assessed daily by an open-field test. Regardless of the polarization direction, functional scores of SCI rats that were treated with the 808-nm laser irradiation were significantly higher than those of SCI alone group (Group 1) from day 5 after injury. The locomotive function of SCI rats irradiated parallel to the spinal column (Group 3) was significantly improved from day 10 after injury, compared to SCI rats treated with the linear polarization perpendicular to the spinal column (Group 2). There were no significant differences in ATP contents in the injured tissue among the three groups. We speculate that the higher efficacy with parallel irradiation is attributable to the deeper light penetration into tissue with anisotropic scattering.
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Affiliation(s)
- Takahiro Ando
- Keio University, Department of Electronics and Electrical Engineering, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Shunichi Sato
- National Defense Medical College Research Institute, Division of Biomedical Information Sciences, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Hiroaki Kobayashi
- National Defense Medical College, Department of Neurosurgery, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Hiroshi Nawashiro
- National Defense Medical College, Department of Neurosurgery, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Hiroshi Ashida
- National Defense Medical College Research Institute, Division of Biomedical Information Sciences, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Michael R. Hamblin
- Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom Street, Boston, Massachusetts 02114
- Harvard Medical School, Department of Dermatology, 55 Fruit Street, Boston, Massachusetts 02115
- Harvard-Massachusetts Institute of Technology (MIT) Division of Health Sciences and Technology, 65 Landsdowne Street, Cambridge, Massachusetts 02139
| | - Minoru Obara
- Keio University, Department of Electronics and Electrical Engineering, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
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Daly SM, Leahy MJ. 'Go with the flow ': a review of methods and advancements in blood flow imaging. JOURNAL OF BIOPHOTONICS 2013; 6:217-55. [PMID: 22711377 DOI: 10.1002/jbio.201200071] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 05/25/2023]
Abstract
Physics has delivered extraordinary developments in almost every facet of modern life. From the humble thermometer and stethoscope to X-Ray, CT, MRI, ultrasound, PET and radiotherapy, our health has been transformed by these advances yielding both morphological and functional metrics. Recently high resolution label-free imaging of the microcirculation at clinically relevant depths has become available in the research domain. In this paper, we present a comprehensive review on current imaging techniques, state-of-the-art advancements and applications, and general perspectives on the prospects for these modalities in the clinical realm.
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Affiliation(s)
- Susan M Daly
- Biophotonics Research Facility, Department of Physics & Energy, University of Limerick, Ireland.
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Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR. The nuts and bolts of low-level laser (light) therapy. J Periodontal Implant Sci 2011; 40:105-10. [PMID: 20607054 PMCID: PMC2895515 DOI: 10.5051/jpis.2010.40.3.105] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 04/20/2010] [Indexed: 01/11/2023] Open
Abstract
Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term "low level laser therapy" or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice. The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy.
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Affiliation(s)
- Hoon Chung
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
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Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng 2011; 40:516-33. [PMID: 22045511 DOI: 10.1007/s10439-011-0454-7] [Citation(s) in RCA: 811] [Impact Index Per Article: 62.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 10/20/2011] [Indexed: 01/03/2023]
Abstract
Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term "low level laser therapy" or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice. The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy.
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Affiliation(s)
- Hoon Chung
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
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16
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Biochemical and anisotropical properties of tendons. Micron 2011; 43:205-14. [PMID: 21890364 DOI: 10.1016/j.micron.2011.07.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 07/26/2011] [Accepted: 07/26/2011] [Indexed: 01/30/2023]
Abstract
Tendons are formed by dense connective tissue composed of an abundant extracellular matrix (ECM) that is constituted mainly of collagen molecules, which are organized into fibrils, fibers, fiber bundles and fascicles helicoidally arranged along the largest axis of the tendon. The biomechanical properties of tendons are directly related to the organization of the collagen molecules that aggregate to become a super-twisted cord. In addition to collagen, the ECM of tendons is composed of non-fibrillar components, such as proteoglycans and non-collagenous glycoproteins. The capacity of tendons to resist mechanical stress is directly related to the structural organization of the ECM. Collagen is a biopolymer and presents optical anisotropies, such as birefringence and linear dichroism, that are important optical properties in the characterization of the supramolecular organization of the fibers. The objective of this study was to present a review of the composition and organization of the ECM of tendons and to highlight the importance of the anisotropic optical properties in the study of alterations in the ECM.
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Peplow PV, Chung TY, Baxter GD. Laser Photobiomodulation of Wound Healing: A Review of Experimental Studies in Mouse and Rat Animal Models. Photomed Laser Surg 2010; 28:291-325. [DOI: 10.1089/pho.2008.2446] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Philip V. Peplow
- Department of Anatomy & Structural Biology, University of Otago, Dunedin, New Zealand
| | - Tzu-Yun Chung
- Department of Anatomy & Structural Biology, University of Otago, Dunedin, New Zealand
| | - G. David Baxter
- Centre for Physiotherapy Research, School of Physiotherapy, University of Otago, Dunedin, New Zealand
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Iordanou P, Lykoudis EG, Athanasiou A, Koniaris E, Papaevangelou M, Fatsea T, Bellou P. Effect of visible and infrared polarized light on the healing process of full-thickness skin wounds: an experimental study. Photomed Laser Surg 2009; 27:261-7. [PMID: 18687058 DOI: 10.1089/pho.2008.2237] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE AND BACKGROUND DATA Polarized light has already been experimentally and clinically used in an effort to promote wound healing, but the findings have been equivocal. The aim of this study was to evaluate the effect of visible and infrared polarized light of a specific range of wavelength (580-3400 nm) on the secondary healing of full-thickness skin wounds in rats. MATERIALS AND METHODS Forty male Wistar rats were used, divided in two groups of 20 animals each. A standardized open full-thickness skin wound was created on the back of each animal. In the first group the rats were exposed to polarized light (40 mW/cm(2) and 2.4 J/cm(2)) for 7 min on a daily basis (total daily dose = 16.8 J/cm(2)), while the second group acted as controls. Clinical and histological evaluation of wound healing were performed on days 5, 10, 15, and 20 post-wound. The size of the wounds was measured with the use of planimetry, whereas epithelialization, inflammatory response, neovascularization, and collagen formation were histologically assessed. RESULTS According to our findings, the group exposed to light therapy showed statistically significantly faster epithelialization seen on days 10 and 15 post-wound compared to controls, as well as better quality of the healing process (although not statistically significantly) at all time points. CONCLUSION In conclusion, this specific fraction of polarized light seems to have beneficial effects on wound healing, leading to faster epithelialization and qualitatively better wound healing.
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Affiliation(s)
- Panagiota Iordanou
- Technological Educational Institute of Athens, Ioannina University School of Medicine, Ioannina, Greece
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Silveira LB, Prates RA, Novelli MD, Marigo HA, Garrocho AA, Amorim JCF, Sousa GR, Pinotti M, Ribeiro MS. Investigation of mast cells in human gingiva following low-intensity laser irradiation. Photomed Laser Surg 2009; 26:315-21. [PMID: 18637717 DOI: 10.1089/pho.2007.2140] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE The aims of the present study were to investigate the effect of low-intensity laser irradiation on the total number of mast cells as well as the percentage of degranulation in human gingiva. Blood vessel dilation was also evaluated. BACKGROUND DATA It has been proposed that low-intensity laser irradiation can ameliorate pain, swelling, and inflammation. In periodontal tissue, mast cells may influence either the destructive events or the defense mechanism against periodontal disease via secretion of cytokines and through cellular migration to improve the healing process. Mast cells play an important role in the inflammatory process. METHODS Twenty patients with gingival enlargement indicated for gingivectomy were selected. Gingival fragments were obtained from each patient and divided into three different groups before surgery. One fragment was removed without any irradiation. The two others were submitted to punctual irradiation with an energy density of 8 J/cm(2) at an output power of 50 mW at 36 Hz for 36 sec before gingivectomy. Nondegranulated and degranulated mast cells were counted in five areas of the gingival fragment connective tissue. Major and minor diameters of the blood vessels were also measured. RESULTS Both red and infrared radiation promoted a significant increase in mast cell degranulation compared to controls; however, no statistically significant differences (p > 0.05) were observed between the irradiated groups. No significant differences among the groups were observed regarding blood vessel size. CONCLUSION The results suggests that red and infrared wavelengths promote mast cell degranulation in human gingival tissue, although no dilation of blood vessels was observed. The effects of premature degranulation of mast cells in human tissue and the laser radiation protocol applied in this study encourage further investigations to extend these results into clinical practice.
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Affiliation(s)
- L B Silveira
- IPEN-CNEN/SP, Cidade Universitária, São Paulo, Brazil
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An in vitro assay of collagen fiber alignment by acupuncture needle rotation. Biomed Eng Online 2008; 7:19. [PMID: 18606012 PMCID: PMC2483714 DOI: 10.1186/1475-925x-7-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 07/07/2008] [Indexed: 02/07/2023] Open
Abstract
Background During traditional acupuncture therapy, soft tissues attach to and wind around the acupuncture needle. To study this phenomenon in a controlled and quantitative setting, we performed acupuncture needling in vitro. Methods Acupuncture was simulated in vitro in three-dimensional, type I collagen gels prepared at 1.5 mg/ml, 2.0 mg/ml, and 2.5 mg/ml collagen, and either crosslinked with formalin or left untreated. Acupuncture needles were inserted into the gels and rotated via a computer-controlled motor at 0.3 rev/sec for up to 10 revolutions while capturing the evolution of birefringence under cross-polarization. Results Simulated acupuncture produced circumferential alignment of collagen fibers close to the needle that evolved into radial alignment as the distance from the needle increased, which generally matched observations from published tissue explant studies. All gels failed prior to 10 revolutions, and the location of failure was near the transition between circumferential and radial alignment. Crosslinked collagen failed at a significantly lower number of revolutions than untreated collagen, whereas collagen concentration had no effect on gel failure. The strength of the alignment field increased with increasing collagen concentration and decreased with crosslinking. Separate studies were performed in which the gel thickness and depth of needle insertion were varied. As gel thickness increased, gels failed at fewer needle revolutions. For the same depth of insertion, alignment was greater in thinner gels. Alignment increased as the depth of insertion increased. Conclusion These results indicate that the mechanostructural properties of soft connective tissues may affect their response to acupuncture therapy. The in vitro model provides a platform to study mechanotransduction during acupuncture in a highly controlled and quantitative setting.
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Aldrovani M, Guaraldo A, Vidal B. Optical anisotropies in corneal stroma collagen fibers from diabetic spontaneous mice. Vision Res 2007; 47:3229-37. [DOI: 10.1016/j.visres.2007.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 01/14/2007] [Accepted: 02/22/2007] [Indexed: 10/22/2022]
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