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Silveira BC, Ribeiro AP, Pizzinatto FD, Lobo PM, Miranda HR, de Assis Pereira N. Effects of commercial amniotic membrane extract on the re-epithelialization time and the early expression of matrix metalloproteinase-9 in cats with experimentally induced corneal ulcers. Vet Ophthalmol 2022; 26 Suppl 1:154-162. [PMID: 36094319 DOI: 10.1111/vop.13024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 08/26/2022] [Accepted: 08/28/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To investigate whether a commercially available amniotic membrane extract (AME) can accelerate corneal wound healing and suppress the early expression of MMP-9 in the tears of cats with experimentally induced superficial ulcerative keratitis. PROCEDURES A total number of 16 cats were included. At the end of keratectomy, cats in the treatment group (TG, n = 8) received 40 μl of AME (EyeQ® Amniotic Eye Drops, Vetrix®) four times daily, while cats in the control group (CG, n = 8) received 40 μl of saline at the same time points. Tears were collected 24 and 48 h after keratectomy, and the total MMP-9 was quantified by ELISA. RESULTS The corneal re-epithelialization rate did not differ between groups (p = .26), being 0.48 ± 0.05 mm2 /h in the CG and 0.41 ± 0.03 mm2 /h in the TG. Similarly, the average time to achieve corneal wound healing did not differ between groups (p = .25) and was 61.50 ± 3.54 h in the CG and 70.50 ± 6.71 h in the TG. The dimensions of the ulcerated areas also did not differ at any time point between the groups (p > .05). In both groups, corneas healed without scarring, pigmentation, or vascularization. The expression of MMP-9 in the tears was similar in both groups at 24 h post-keratectomy, with a slight decrease at 48 h (p > .05). CONCLUSIONS The instillation of a commercial AME (EyeQ®) is safe, but it did not decrease the corneal re-epithelialization time or the early expression of MMP-9 in the tears of cats with experimentally induced superficial ulcerative keratitis in this study.
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Affiliation(s)
| | | | | | - Paloma Moraes Lobo
- Faculdade de Medicina Veterinária, Universidade Federal de Mato Grosso, Cuiabá, Brazil
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Biochemistry of human tear film: A review. Exp Eye Res 2022; 220:109101. [DOI: 10.1016/j.exer.2022.109101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022]
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Sebbag L, Mochel JP. An eye on the dog as the scientist's best friend for translational research in ophthalmology: Focus on the ocular surface. Med Res Rev 2020; 40:2566-2604. [PMID: 32735080 DOI: 10.1002/med.21716] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/01/2020] [Accepted: 07/15/2020] [Indexed: 12/15/2022]
Abstract
Preclinical animal studies provide valuable opportunities to better understand human diseases and contribute to major advances in medicine. This review provides a comprehensive overview of ocular parameters in humans and selected animals, with a focus on the ocular surface, detailing species differences in ocular surface anatomy, physiology, tear film dynamics and tear film composition. We describe major pitfalls that tremendously limit the translational potential of traditional laboratory animals (i.e., rabbits, mice, and rats) in ophthalmic research, and highlight the benefits of integrating companion dogs with clinical analogues to human diseases into preclinical pharmacology studies. This One Health approach can help accelerate and improve the framework in which ophthalmic research is translated to the human clinic. Studies can be conducted in canine subjects with naturally occurring or noninvasively induced ocular surface disorders (e.g., dry eye disease, conjunctivitis), reviewed herein, and tear fluid can be easily retrieved from canine eyes for various bioanalytical purposes. In this review, we discuss common tear collection methods, including capillary tubes and Schirmer tear strips, and provide guidelines for tear sampling and extraction to improve the reliability of analyte quantification (drugs, proteins, others).
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Affiliation(s)
- Lionel Sebbag
- Department of Biomedical Sciences, SMART Pharmacology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA.,Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Jonathan P Mochel
- Department of Biomedical Sciences, SMART Pharmacology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
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The Protective Effect of an Eye Wash Solution on the Ocular Surface Damage Induced by Airborne Carbon Black Exposure. Cornea 2020; 39:1040-1047. [PMID: 32141942 DOI: 10.1097/ico.0000000000002304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To investigate the effects of an eye wash solution on the ocular surface damage induced by airborne carbon black (CB) exposure. METHODS Sprague-Dawley rats were exposed to ambient CB for 5 days. During the 5 days, a commercial eye wash solution (Eyebon-W) was used for irrigation twice daily on CB-exposed rat eyes; normal saline was used as the vehicle control. Lactic dehydrogenase (LDH) activity and matrix metallopeptidase (MMP)-9, histamine, and lactoferrin levels were measured in tears. The expression of inflammatory cytokines in the anterior segment of the eyeball was measured by Western blot analysis. RESULTS The ocular surface staining scores, tear LDH activity, tear MMP-9, histamine, and lactoferrin concentrations, and the expression of interleukin-4 and interferon-γ in the eye were significantly increased in the CB group versus the normal control group. When compared with CB group, the Eyebon-W eye wash treatment significantly reversed these elevations induced by CB, including ocular staining scores, tear LDH activity, histamine and MMP-9 concentrations in the tear fluid, and the expression of interleukin-4 in the eye. On the other hand, saline irrigation only reduced the concentrations of histamine and MMP-9 in tear fluid and the expression of interferon-γ in the eye. CONCLUSIONS Both Eyebon-W eye wash treatment and saline irrigation reversed CB-induced ocular surface injury, but the efficacy of Eyebon-W was more significant than that of the saline solution when compared with CB group. The use of an eye wash solution seems to play a protective role for the ocular surface when exposed to airborne particulate matter.
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An Omics Approach to Diagnosing or Investigating Fungal Keratitis. Int J Mol Sci 2019; 20:ijms20153631. [PMID: 31349542 PMCID: PMC6695605 DOI: 10.3390/ijms20153631] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/21/2019] [Accepted: 07/23/2019] [Indexed: 02/05/2023] Open
Abstract
Fungal keratitis (FK) is one of the most severe corneal infectious diseases. FK often leads to poor visual prognosis and thus requires accurate diagnosis. Conventional approaches, including clinical diagnoses, smears, and cultures, often fail to provide reliable diagnostic value. Omics approaches, such as those using genomic, metagenomic, and tear proteomic data sources, provide promising features for improving the diagnosis and monitoring the progression of FK. Genomic approaches are based mainly on detecting amplicons of ribosomal RNA genes, and internal transcribed spacers are gradually gaining popularity in clinical practices. A metagenomic approach based on 16S rRNA genes may help monitor the dynamic change of conjunctival microbiota associated with an FK event, whereas that based on shot-gun and 18S rRNA target enrichment sequencing could have the potential to diagnose FK using clinical samples. A tear proteomic approach may provide comprehensive information about ocular surface defense and injury during FK. Representative up- and down-regulated proteins during FK could also be used as biomarkers to determine the clinical course and develop a treatment strategy in different stages of FK. Consequently, a personalized tear proteomic approach will soon play a key role in FK management.
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Li X, Kang B, Eom Y, Lee HK, Kim HM, Song JS. The Protective Effect of a Topical Mucin Secretagogue on Ocular Surface Damage Induced by Airborne Carbon Black Exposure. Invest Ophthalmol Vis Sci 2019; 60:255-264. [PMID: 30649152 DOI: 10.1167/iovs.18-25964] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Exposure to airborne particulate matter can induce ocular surface damage and inflammation. We evaluated the effects of a topical mucin secretagogue on the mitigation of ocular surface damage induced by exposure to airborne carbon black (CB). Methods Sprague-Dawley rats were exposed to ambient CB for 2 hours twice daily for 5 days. Corneal staining score and tear lactic dehydrogenase (LDH) activity were measured to evaluate ocular surface damage. Serum immunoglobulin (Ig) G and IgE levels and the sizes of cervical lymph nodes were also measured. The expressions of interleukin (IL)-4, IL-17, and interferon (IFN)-γ were measured by Western blot analysis. Diquafosol tetrasodium was instilled six times a day for 5 days, and the extent of ocular surface damage was evaluated. Results After exposure to airborne CB, the median corneal staining score and LDH activity were significantly increased. Serum IgG and IgE levels and the sizes of cervical lymph nodes were also significantly increased. Additionally, the expression of IL-4 and IFN-γ was elevated in the anterior segment of the eyeball. Furthermore, the expression of IL-4, IL-17, and IFN-γ was elevated in the cervical lymph nodes. When exposed to airborne black carbon, topical diquafosol tetrasodium significantly increased tear MUC5AC concentration and decreased tear LDH activity. Conclusions Exposure to airborne CB induced ocular surface damage and increased proinflammatory cytokines in the eyes and cervical lymph nodes. Topical mucin secretagogues seem to have a protective effect on the ocular surface against exposure to airborne particulate matters.
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Affiliation(s)
- Xiangzhe Li
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Boram Kang
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Youngsub Eom
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Hyung Keun Lee
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
| | - Hyo Myung Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Jong Suk Song
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
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Meibomian Glands and Ocular Surface Changes After Closure of Meibomian Gland Orifices in Rabbits. Cornea 2018; 37:218-226. [PMID: 29189289 DOI: 10.1097/ico.0000000000001460] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate changes in the corneal surface, tear film, and meibomian glands after meibomian gland orifice closure. METHODS Seventy-two eyes of 36 rabbits were used. In the study group (n = 36), the meibomian gland orifices of both upper and lower eyelids in the right eyes were electrosurgically coagulated. The 36 untreated left eyes were used as controls. Corneal wetting properties were measured 1, 3, 7, and 14 days after coagulation. The eyelid sections were stained with anti-cytokeratin (CK)1, CK5, and CK6 antibody 8 weeks after coagulation. The area of the secretory acini around one meibomian gland duct was measured, and meibography of rabbits was performed 8 weeks after meibomian gland orifice closure. RESULTS Three days after coagulation, the corneal wetting property was decreased compared with controls. The meibomian gland ducts gradually dilated in the study group over time. The epithelium of the central ducts in both groups was stained with CK5 and CK6, but not CK1. Although the mean area of the secretory acini in the study group (0.10 ± 0.04 mm) was significantly smaller than that of the control group (0.18 ± 0.04; P = 0.004), meibography showed normal morphology in both study and control groups. CONCLUSIONS Meibomian gland orifice closure reduced corneal wetting property and induced meibomian gland duct dilation accompanied by shrinkage of secretory acini. Meibography could not detect early changes in the meibomian gland after closure of the orifice. Therefore, when the orifice is obstructed, more active treatments are needed before structural changes occur.
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Sebbag L, McDowell EM, Hepner PM, Mochel JP. Effect of tear collection on lacrimal total protein content in dogs and cats: a comparison between Schirmer strips and ophthalmic sponges. BMC Vet Res 2018; 14:61. [PMID: 29490661 PMCID: PMC5831202 DOI: 10.1186/s12917-018-1390-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 02/23/2018] [Indexed: 12/27/2022] Open
Abstract
Background Quantification of lacrimal total protein content (TPC) is an important tool for clinical scientists to understand disease pathogenesis, identify potential biomarkers and assess response to therapy, among other applications. However, TPC is not only affected by disease state but also by the method used for tear collection. Thus, the purpose of this study is to determine the impact on TPC of two methods of tear collection in dogs and cats: Schirmer strips and polyvinyl acetal (PVA) sponges. Methods (i) In vivo - Ten healthy dogs and 10 healthy cats were examined. Each animal underwent two sessions, separated by 10 min, in which a Schirmer strip was placed in one randomly selected eye until the 20-mm mark was reached, while a strip of PVA sponge was placed in the other eye for 1 min. (ii) In vitro - Schirmer strips and PVA sponges were spiked with various volumes of four bovine serum albumin solutions (0.5, 4, 10, and 20 mg/mL). In both experiments, the wetted absorbent materials were centrifuged for 1 min, and the TPC was quantified on the extracted fluid using Direct Detect™ infrared spectroscopy. Results Lacrimal TPC in dogs and cats ranged from 5.2 to 14.6 mg/mL and from 6.2 to 20.6 mg/mL, respectively. In cats, TPC was significantly lower with Schirmer strips vs. PVA sponges (P < 0.001). In dogs, the volume absorbed by PVA sponges was negatively correlated with TPC (r = − 0.48, P = 0.033). The inter-session coefficient of variation was significantly lower with Schirmer strips vs. PVA sponges in both species (P ≤ 0.010). In vitro, both absorbent materials resulted in a ‘concentrating effect’ of the TPC obtained post-centrifugation, which was most pronounced when the volume absorbed was low, especially for Schirmer strips. Conclusion Schirmer strips provide a repeatable method to quantify lacrimal TPC in dogs and cats, although care should be taken to absorb sufficient volumes of tears to minimize the concentrating effect from the absorbent material.
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Affiliation(s)
- Lionel Sebbag
- Department of Veterinary Clinical Sciences, Iowa State University, College of Veterinary Medicine, Ames, IA, 50011, USA.
| | - Emily M McDowell
- Lloyd Veterinary Medical Center, Iowa State University, College of Veterinary Medicine, Ames, IA, 50011, USA
| | - Patrick M Hepner
- Lloyd Veterinary Medical Center, Iowa State University, College of Veterinary Medicine, Ames, IA, 50011, USA
| | - Jonathan P Mochel
- Department of Biomedical sciences, Iowa State University, College of Veterinary Medicine, Ames, IA, 50011, USA
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Sebbag L, Harrington DM, Mochel JP. Tear fluid collection in dogs and cats using ophthalmic sponges. Vet Ophthalmol 2017; 21:249-254. [DOI: 10.1111/vop.12502] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lionel Sebbag
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine; Iowa State University; Ames IA USA
| | - Danielle M. Harrington
- Lloyd Veterinary Medical Center; College of Veterinary Medicine; Iowa State University; Ames IA USA
| | - Jonathan P. Mochel
- Department of Biomedical Sciences; College of Veterinary Medicine; Iowa State University; Ames IA USA
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Rentka A, Koroskenyi K, Harsfalvi J, Szekanecz Z, Szucs G, Szodoray P, Kemeny-Beke A. Evaluation of commonly used tear sampling methods and their relevance in subsequent biochemical analysis. Ann Clin Biochem 2017; 54:521-529. [DOI: 10.1177/0004563217695843] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The human precorneal tear film is a special body fluid, since it is a complex mixture of proteins, lipids, small bioactive molecules, and their concentrations and relative distribution represent not only the metabolic state of the ocular surface but also the systemic and local homeostasis of the outer eye and the human body. This suggests that biochemical analysis of the precorneal tear film composition may provide a non-invasive tool for diagnosis and monitoring of disease progression or treatment efficacy in human medicine. However, collecting tears is demanding, and obtaining reproducible and unaltered samples is challenging because of the small sample volumes of tears. Several methods are available for tear collection as a preparatory step of precorneal tear film analysis, and the collection method used has to be assessed since it has a critical impact on the effectiveness of the assays and on the quality of the results. Each sampling method has advantages and disadvantages; therefore, it is not easy to choose the appropriate collecting method for tear collection. To overcome these limitations various methods have been recommended by different authors for special aspects of specific tests. The aim of our review was to evaluate tear sampling methods with regard to our ongoing biochemical analysis.
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Affiliation(s)
- Aniko Rentka
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Koroskenyi
- Department of Biochemistry and Molecular Biology, Signaling and Apoptosis Research Group, Hungarian Academy of Sciences, Research Center of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Jolan Harsfalvi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Zoltan Szekanecz
- Department of Rheumatology, Institute of Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gabriella Szucs
- Department of Rheumatology, Institute of Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Peter Szodoray
- Institute of Immunology, Rikshospitalet, Oslo University Hospital, Oslo, Norway
| | - Adam Kemeny-Beke
- Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Petznick A, Madigan MC, Garrett Q, Sweeney DF, Evans MDM. Contributions of ocular surface components to matrix-metalloproteinases (MMP)-2 and MMP-9 in feline tears following corneal epithelial wounding. PLoS One 2013; 8:e71948. [PMID: 23977185 PMCID: PMC3747068 DOI: 10.1371/journal.pone.0071948] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 07/05/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose This study investigated ocular surface components that contribute to matrix-metalloproteinase (MMP)-2 and MMP-9 found in tears following corneal epithelial wounding. Methods Laboratory short-haired cats underwent corneal epithelial debridement in one randomly chosen eye (n = 18). Eye-flush tears were collected at baseline and during various healing stages. Procedural control eyes (identical experimental protocol as wounded eyes except for wounding, n = 5) served as controls for tear analysis. MMP activity was analyzed in tears using gelatin zymography. MMP staining patterns were evaluated in ocular tissues using immunohistochemistry and used to determine MMP expression sites responsible for tear-derived MMPs. Results The proMMP-2 and proMMP-9 activity in tears was highest in wounded and procedural control eyes during epithelial migration (8 to 36 hours post-wounding). Wounded eyes showed significantly higher proMMP-9 in tears only during and after epithelial restratification (day 3 to 4 and day 7 to 28 post-wounding, respectively) as compared to procedural controls (p<0.05). Tears from wounded and procedural control eyes showed no statistical differences for pro-MMP-2 and MMP-9 (p>0.05). Immunohistochemistry showed increased MMP-2 and MMP-9 expression in the cornea during epithelial migration and wound closure. The conjunctival epithelium exhibited highest levels of both MMPs during wound closure, while MMP-9 expression was reduced in conjunctival goblet cells during corneal epithelial migration followed by complete absence of the cells during wound closure. The immunostaining for both MMPs was elevated in the lacrimal gland during corneal healing, with little/no change in the meibomian glands. Conjunctival-associated lymphoid tissue (CALT) showed weak MMP-2 and intense MMP-9 staining. Conclusions Following wounding, migrating corneal epithelium contributed little to the observed MMP levels in tears. The major sources assessed in the present study for tear-derived MMP-2 and MMP-9 following corneal wounding are the lacrimal gland and CALT. Other sources included stromal keratocytes and conjunctiva with goblet cells.
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Affiliation(s)
- Andrea Petznick
- Vision CRC, Sydney, Australia ; School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Guyette N, Williams L, Tran MT, Than T, Bradley J, Kehinde L, Edwards C, Beasley M, Fullard R. Comparison of low-abundance biomarker levels in capillary-collected nonstimulated tears and washout tears of aqueous-deficient and normal patients. Invest Ophthalmol Vis Sci 2013; 54:3729-37. [PMID: 23611994 DOI: 10.1167/iovs.12-11431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Low tear volume limits the use of nonstimulated (NS) microcapillary tear collection in aqueous-deficient (AD) patients. Adding a small amount of "washout" fluid to the eye prior to tear collection is a potentially viable alternative method for abundant proteins, but is relatively untested for low-abundance biomarkers. This study determined the feasibility of the washout (WO) method as an NS alternative for low-abundance biomarkers. NS and WO biomarker profiles were compared between AD patients and non-AD controls to determine if the two methods identify the same intergroup differences. METHODS Matching NS and WO tears were collected from 48 patients by micropipette, the WO sample after instillation of 10 μL saline. Tear cytokine levels were measured by 27-Plex Bio-Rad assay. Bland-Altman analyses for each biomarker determined the agreement between tear sample types. Patients were grouped as AD or non-AD based on Schirmer score to determine if NS profile between-group differences were preserved in WO tears. RESULTS Bland-Altman plots showed good biomarker level agreement between NS and WO tears for most cytokines. Five biomarkers, among those most often cited as differing in AD dry eye, differed significantly between non-AD and AD groups in both tear types. Additional biomarker differences were seen in NS tears only. CONCLUSIONS The WO tear collection method is a viable alternative to NS tears for many low-abundance biomarkers and is able to replicate major NS tear differences between dry eye groups. More subtle intergroup differences are lost in WO samples because of reduced statistical power.
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Affiliation(s)
- Nicole Guyette
- Department of Vision Sciences, School of Optometry, University of Alabama-Birmingham, Birmingham, AL 35294, USA
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Farias E, Yasunaga KL, Peixoto RV, Fonseca MP, Fontes W, Galera PD. Comparison of two methods of tear sampling for protein quantification by Bradford method. PESQUISA VETERINARIA BRASILEIRA 2013. [DOI: 10.1590/s0100-736x2013000200021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to compare two methods of tear sampling for protein quantification. Tear samples were collected from 29 healthy dogs (58 eyes) using Schirmer tear test (STT) strip and microcapillary tubes. The samples were frozen at -80ºC and analyzed by the Bradford method. Results were analyzed by Student's t test. The average protein concentration and standard deviation from tears collected with microcapillary tube were 4.45mg/mL ±0.35 and 4,52mg/mL ±0.29 for right and left eyes respectively. The average protein concentration and standard deviation from tears collected with Schirmer Tear Test (STT) strip were and 54.5mg/mL ±0.63 and 54.15mg/mL ±0.65 to right and left eyes respectively. Statistically significant differences (p<0.001) were found between the methods. In the conditions in which this study was conducted, the average protein concentration obtained with the Bradford test from tear samples obtained by Schirmer Tear Test (STT) strip showed values higher than those obtained with microcapillary tube. It is important that concentration of tear protein pattern values should be analyzed according the method used to collect tear samples.
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Petznick A, Evans MDM, Madigan MC, Garrett Q, Sweeney DF. A preliminary study of changes in tear film proteins in the feline eye following nictitating membrane removal. Vet Ophthalmol 2011; 15:164-71. [PMID: 22050623 DOI: 10.1111/j.1463-5224.2011.00955.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the influence of nictitating membrane (third eyelid) removal on selected proteins in feline tears. ANIMAL STUDIED Domestic short-haired cats (7-17 months; 2.6-5.2 kg) were used. PROCEDURES Eye-flush tears were collected periodically for up to 18 weeks from both eyes of animals with nictitating membranes removed, but nictitating gland left intact, (n = 4) or with nictitating membranes intact (n = 4). Tear comparisons were based on total protein content (TPC) using micro bicinchoninic acid assay, immunoglobulin A (IgA), and matrix-metalloproteinase (MMP)-9 measurements using sandwich enzyme-linked immunosorbent assay (ELISA) and tear gelatinase activity using gelatin zymography. Expression of MMP-2 and -9 in nictitating membranes removed at baseline (week 0) and eyes collected at 18 weeks were also investigated in histological sections using immunoperoxidase for visualization. RESULTS Nictitating membrane removal did not significantly change TPC and MMP-9 in tears within the first 4 weeks. MMP-9 was not detected by ELISA in tears from eyes without nictitating membranes from week 5 onwards. IgA (%IgA of TPC) data varied between animals. Gelatin zymography showed increased MMP-2 and -9 activity in tears from eyes without nictitating membranes at week 1 and a decrease following week 2 post-surgery. MMP-2 and -9 were immunolocalised to conjunctival goblet cells of removed nictitating membranes and to the conjunctival epithelium, respectively. After 18 weeks, the distribution of MMPs in tissue was comparable between eyes with and without nictitating membranes. CONCLUSIONS Based on this preliminary study, nictitating membrane removal appeared to cause long-term changes in expression of tear proteins, including reduced MMP-9 expression.
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