{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T02:38:12Z","timestamp":1774665492729,"version":"3.50.1"},"reference-count":48,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2024,8,19]],"date-time":"2024-08-19T00:00:00Z","timestamp":1724025600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Italian Ministry of University and Research and from the University of Pisa"}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Pathogens"],"abstract":"<jats:p>Ocular toxoplasmosis is the most prevalent clinical manifestation of T. gondii infection, which causes irreversible retinal damage. Different experimental models have been developed to study this pathology. In the present study, a new, ex vivo model is proposed to contribute to the elucidation of disease mechanisms and to possible therapeutic solutions. Ex-vivo retinal explants, prepared from mouse retinas following established protocols, were incubated with T. gondii tachyzoites maintained in Vero cells. At different times, starting at 12 h up to 10 days of incubation, the explants were analyzed with immunofluorescence and Western blot to investigate their responses to parasite infection. T. gondii invasion of the retinal thickness was evident after 3 days in culture, where parasites could be detected around retinal cell nuclei. This was paralleled by putative cyst formation and microglial activation. At the same time, an evident increase in inflammatory and oxidative stress markers was detected in infected explants compared to controls. Cell death also appeared to occur in retinal explants after 3 days of T. gondii infection, and it was characterized by increased necroptotic but not apoptotic markers. The proposed model recapitulates the main characteristics of T. gondii retinal infection within 3 days of incubation and, therefore, allows for studying the very early events of the process. In addition, it requires only a limited number of animals and offers easy manipulation and accessibility for setting up different experimental conditions and assessing the effects of putative drugs for therapy.<\/jats:p>","DOI":"10.3390\/pathogens13080701","type":"journal-article","created":{"date-parts":[[2024,8,20]],"date-time":"2024-08-20T01:38:45Z","timestamp":1724117925000},"page":"701","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["A New Ex Vivo Model Based on Mouse Retinal Explants for the Study of Ocular Toxoplasmosis"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3499-2792","authenticated-orcid":false,"given":"Veronica","family":"Rodriguez Fernandez","sequence":"first","affiliation":[{"name":"Department of Translational Research, School of Medicine, University of Pisa, 56126 Pisa, Italy"},{"name":"Department of Infectious Diseases and Public Health, La Sapienza University, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8386-4714","authenticated-orcid":false,"given":"Rosario","family":"Amato","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Pisa, 56126 Pisa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simona","family":"Piaggi","sequence":"additional","affiliation":[{"name":"Department of Translational Research, School of Medicine, University of Pisa, 56126 Pisa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barbara","family":"Pinto","sequence":"additional","affiliation":[{"name":"Department of Translational Research, School of Medicine, University of Pisa, 56126 Pisa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0270-4437","authenticated-orcid":false,"given":"Giovanni","family":"Casini","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Pisa, 56126 Pisa, Italy"},{"name":"Interdepartmental Research Center Nutrafood \u201cNutraceuticals and Food for Health\u201d, University of Pisa, 56126 Pisa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8701-3290","authenticated-orcid":false,"given":"Fabrizio","family":"Bruschi","sequence":"additional","affiliation":[{"name":"Department of Translational Research, School of Medicine, University of Pisa, 56126 Pisa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1038\/eye.2011.331","article-title":"Toxoplasmosis: New challenges for an old disease","volume":"26","author":"Bodaghi","year":"2012","journal-title":"Eye"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"68","DOI":"10.3109\/09273948.2012.661115","article-title":"Epidemiology of ocular toxoplasmosis","volume":"20","author":"Petersen","year":"2012","journal-title":"Ocul. Immunol. Inflamm."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1111\/j.1442-9071.2012.02821.x","article-title":"Ocular toxoplasmosis I: Parasitology, epidemiology and public health","volume":"41","author":"Furtado","year":"2013","journal-title":"Clin. Exp. Ophthalmol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"50","DOI":"10.3390\/parasitologia1020007","article-title":"Ocular Toxoplasmosis: Mechanisms of Retinal Infection and Experimental Models","volume":"1","author":"Casini","year":"2021","journal-title":"Parasitologia"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1111\/j.1442-9071.2012.02838.x","article-title":"Ocular toxoplasmosis II: Clinical features, pathology and management","volume":"41","author":"Butler","year":"2013","journal-title":"Clin. Exp. Ophthalmol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1556\/1886.2015.00045","article-title":"Experimental Models of Ocular Infection with Toxoplasma gondii","volume":"5","author":"Dukaczewska","year":"2015","journal-title":"Eur. J. Microbiol. Immunol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2813","DOI":"10.1167\/iovs.04-0177","article-title":"Cultured embryonic retina systems as a model for the study of underlying mechanisms of Toxoplasma gondii infection","volume":"45","author":"Moraes","year":"2004","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Furtado, J.M., Ashander, L.M., Mohs, K., Chipps, T.J., Appukuttan, B., and Smith, J.R. (2013). Toxoplasma gondii migration within and infection of human retina. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0054358"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3066","DOI":"10.1167\/iovs.16-19285","article-title":"VEGF as a Survival Factor in Ex Vivo Models of Early Diabetic Retinopathy","volume":"57","author":"Amato","year":"2016","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/j.phrs.2017.09.022","article-title":"Autophagy-mediated neuroprotection induced by octreotide in an ex vivo model of early diabetic retinopathy","volume":"128","author":"Amato","year":"2018","journal-title":"Pharmacol. Res."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Amato, R., Giannaccini, M., Dal Monte, M., Cammalleri, M., Pini, A., Raffa, V., Lulli, M., and Casini, G. (2020). Association of the Somatostatin Analog Octreotide With Magnetic Nanoparticles for Intraocular Delivery: A Possible Approach for the Treatment of Diabetic Retinopathy. Front. Bioeng. Biotechnol., 8.","DOI":"10.3389\/fbioe.2020.00144"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Amato, R., Rossino, M.G., Cammalleri, M., Locri, F., Pucci, L., Dal Monte, M., and Casini, G. (2018). Lisosan G Protects the Retina from Neurovascular Damage in Experimental Diabetic Retinopathy. Nutrients, 10.","DOI":"10.3390\/nu10121932"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Rossino, M.G., Amato, R., Amadio, M., Rosini, M., Basagni, F., Cammalleri, M., Dal Monte, M., and Casini, G. (2021). A Nature-Inspired Nrf2 Activator Protects Retinal Explants from Oxidative Stress and Neurodegeneration. Antioxidants, 10.","DOI":"10.3390\/antiox10081296"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Rossino, M.G., Lulli, M., Amato, R., Cammalleri, M., Monte, M.D., and Casini, G. (2020). Oxidative Stress Induces a VEGF Autocrine Loop in the Retina: Relevance for Diabetic Retinopathy. Cells, 9.","DOI":"10.3390\/cells9061452"},{"key":"ref_15","first-page":"125","article-title":"Optimization of Toxoplasma gondii cultivation in VERO cell line","volume":"27","author":"Saadatnia","year":"2010","journal-title":"Trop. Biomed."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Guo, L., Choi, S., Bikkannavar, P., and Cordeiro, M.F. (2022). Microglia: Key Players in Retinal Ageing and Neurodegeneration. Front. Cell Neurosci., 16.","DOI":"10.3389\/fncel.2022.804782"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1007\/s10792-024-02985-2","article-title":"An alternative method to establish an early acute ocular toxoplasmosis model for experimental tests","volume":"44","author":"Vommaro","year":"2024","journal-title":"Int. Ophthalmol."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Greigert, V., Bittich-Fahmi, F., and Pfaff, A.W. (2020). Pathophysiology of ocular toxoplasmosis: Facts and open questions. PLoS Negl. Trop. Dis., 14.","DOI":"10.1371\/journal.pntd.0008905"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1111\/j.1600-0463.2009.02453.x","article-title":"Communication between Toxoplasma gondii and its host: Impact on parasite growth, development, immune evasion, and virulence","volume":"117","author":"Blader","year":"2009","journal-title":"Apmis"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.micinf.2004.09.016","article-title":"Stage conversion of Toxoplasma gondii RH parasites in mice by treatment with atovaquone and pyrrolidine dithiocarbamate","volume":"7","author":"Klun","year":"2005","journal-title":"Microbes Infect."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"36491","DOI":"10.7554\/eLife.36491","article-title":"Dissection of the in vitro developmental program of Hammondia hammondi reveals a link between stress sensitivity and life cycle flexibility in Toxoplasma gondii","volume":"22","author":"Sokol","year":"2018","journal-title":"Elife"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2597","DOI":"10.1007\/s00436-018-5950-3","article-title":"Investigation of tissue cysts in the retina in a mouse model of ocular toxoplasmosis: Distribution and interaction with glial cells","volume":"117","author":"Song","year":"2018","journal-title":"Parasitol. Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1016\/j.taap.2013.01.024","article-title":"Diclofenac enhances proinflammatory cytokine-induced phagocytosis of cultured microglia via nitric oxide production","volume":"268","author":"Kakita","year":"2013","journal-title":"Toxicol. Appl. Pharmacol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"566","DOI":"10.1002\/dneu.22333","article-title":"Nitric oxide regulates antagonistically phagocytic and neurite outgrowth inhibiting capacities of microglia","volume":"76","author":"Scheiblich","year":"2016","journal-title":"Dev. Neurobiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1186\/s12974-021-02251-7","article-title":"Rapid morphologic changes to microglial cells and upregulation of mixed microglial activation state markers induced by P2X7 receptor stimulation and increased intraocular pressure","volume":"18","author":"Campagno","year":"2021","journal-title":"J. Neuroinflamm."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1186\/s12974-018-1346-7","article-title":"Reduced AMPK activation and increased HCAR activation drive anti-inflammatory response and neuroprotection in glaucoma","volume":"15","author":"Inman","year":"2018","journal-title":"J. Neuroinflamm."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1002\/cbin.11710","article-title":"An in vitro cell model to study microglia activation in diabetic retinopathy","volume":"46","author":"Xie","year":"2022","journal-title":"Cell Biol. Int."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.preteyeres.2007.01.004","article-title":"Nitric oxide: Ocular blood flow, glaucoma, and diabetic retinopathy","volume":"26","author":"Toda","year":"2007","journal-title":"Prog. Retin. Eye Res."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1038\/21218","article-title":"Regulation of endothelium-derived nitric oxide production by the protein kinase Akt","volume":"399","author":"Fulton","year":"1999","journal-title":"Nature"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"64944","DOI":"10.7554\/eLife.64944","article-title":"eNOS-induced vascular barrier disruption in retinopathy by c-Src activation and tyrosine phosphorylation of VE-cadherin","volume":"28","author":"Ninchoji","year":"2021","journal-title":"Elife"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1097\/00001756-200303030-00007","article-title":"Change in endothelial nitric oxide synthase in the rat retina following transient ischemia","volume":"14","author":"Cheon","year":"2003","journal-title":"Neuroreport"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Oeckinghaus, A., and Ghosh, S. (2009). The NF-kappaB family of transcription factors and its regulation. Cold Spring Harb. Perspect. Biol., 1.","DOI":"10.1101\/cshperspect.a000034"},{"key":"ref_33","first-page":"28","article-title":"Interleukin-6 and chronic inflammation","volume":"2","author":"Gabay","year":"2006","journal-title":"Arthritis Res. Ther."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2589","DOI":"10.1128\/IAI.69.4.2589-2595.2001","article-title":"Immunological studies of chronic ocular toxoplasmosis: Up-regulation of major histocompatibility complex class I and transforming growth factor beta and a protective role for interleukin-6","volume":"69","author":"Lyons","year":"2001","journal-title":"Infect. Immun."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1111\/j.1550-7408.1995.tb01556.x","article-title":"A cell culture system for study of the development of Toxoplasma gondii bradyzoites","volume":"42","author":"Weiss","year":"1995","journal-title":"J. Eukaryot. Microbiol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.lfs.2019.05.038","article-title":"MMP targeting in the battle for vision: Recent developments and future prospects in the treatment of diabetic retinopathy","volume":"229","author":"Drankowska","year":"2019","journal-title":"Life Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"28800","DOI":"10.3390\/ijms161226131","article-title":"Possible Mechanisms of Di(2-ethylhexyl) Phthalate-Induced MMP-2 and MMP-9 Expression in A7r5 Rat Vascular Smooth Muscle Cells","volume":"16","author":"Shih","year":"2015","journal-title":"Int. J. Mol. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/j.vetpar.2011.11.035","article-title":"Secretion of multi-protein migratory complex induced by Toxoplasma gondii infection in macrophages involves the uPA\/uPAR activation system","volume":"186","author":"Schuindt","year":"2012","journal-title":"Vet. Parasitol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"312","DOI":"10.1016\/j.vetpar.2009.12.042","article-title":"Toxoplasma gondii infection positively modulates the macrophages migratory molecular complex by increasing matrix metalloproteinases, CD44 and alpha v beta 3 integrin","volume":"169","author":"Seipel","year":"2010","journal-title":"Vet. Parasitol."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"B\u00f6hm, E.W., Buonfiglio, F., Voigt, A.M., Bachmann, P., Safi, T., Pfeiffer, N., and Gericke, A. (2023). Oxidative stress in the eye and its role in the pathophysiology of ocular diseases. Redox. Biol., 68.","DOI":"10.1016\/j.redox.2023.102967"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1255","DOI":"10.1016\/0006-2952(91)90666-S","article-title":"Loss of membrane protein thiols and lipid peroxidation in allyl alcohol hepatotoxicity","volume":"41","author":"Pompella","year":"1991","journal-title":"Biochem. Pharmacol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/S0098-2997(03)00023-2","article-title":"4-hydroxynonenal as a bioactive marker of pathophysiological processes","volume":"24","author":"Zarkovic","year":"2003","journal-title":"Mol. Aspects Med."},{"key":"ref_43","first-page":"41","article-title":"Indirect immunofluorescence detection of protein-bound 4-hydroxynonenal in tissue sections and isolated cells","volume":"196","author":"Pompella","year":"2002","journal-title":"Methods Mol. Biol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1106","DOI":"10.1038\/s41423-020-00630-3","article-title":"Necroptosis, pyroptosis and apoptosis: An intricate game of cell death","volume":"18","author":"Bertheloot","year":"2021","journal-title":"Cell Mol. Immunol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1038\/nature14191","article-title":"Necroptosis and its role in inflammation","volume":"517","author":"Pasparakis","year":"2015","journal-title":"Nature"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1038\/sj.cdd.4401724","article-title":"Classification of cell death: Recommendations of the Nomenclature Committee on Cell Death","volume":"2","author":"Kroemer","year":"2005","journal-title":"Cell Death Differ."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"7719","DOI":"10.1038\/sj.onc.1203249","article-title":"More than one way to die: Apoptosis, necrosis and reactive oxygen damage","volume":"18","author":"Fiers","year":"1999","journal-title":"Oncogene"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1695","DOI":"10.1038\/s12276-022-00868-z","article-title":"Roles of RIPK3 in necroptosis, cell signaling, and disease","volume":"54","author":"Morgan","year":"2022","journal-title":"Exp. Mol. Med."}],"updated-by":[{"DOI":"10.3390\/pathogens14121229","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2024,8,19]],"date-time":"2024-08-19T00:00:00Z","timestamp":1724025600000}}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/13\/8\/701\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,5]],"date-time":"2025-12-05T17:53:16Z","timestamp":1764957196000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/13\/8\/701"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,8,19]]},"references-count":48,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2024,8]]}},"alternative-id":["pathogens13080701"],"URL":"https:\/\/doi.org\/10.3390\/pathogens13080701","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,8,19]]}}}