Schizophrenia: Effect of Fluanxol® treatment on redox status
| dc.contributor.advisor | Smith, Carine | en_ZA |
| dc.contributor.author | Annandale, Jenna Fay | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Science. Dept. of Physiological Sciences. | en_ZA |
| dc.date.accessioned | 2021-05-18T09:42:10Z | |
| dc.date.available | 2021-05-18T09:42:10Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MSc)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Oxidative stress has been implicated in the pathology of schizophrenia, with impaired antioxidant mechanisms observed in these patients. The modulatory role of oxidative stress on the activity of NMDA receptors on GABA interneurons impacts neurotransmitter signalling, leading to hyperdopaminergic dysfunction (directly associated with the disease symptoms), microglial activation and a pro-inflammatory shift, rendering these patients susceptible to inflammatory comorbidities. It is therefore important to investigate therapeutic drugs prescribed to schizophrenia patients for their effect on redox status. Flupentixol dihydrochloride (Fluanxol®) is prescribed to patients with schizophrenia and has known antipsychotic effects. However, the mechanisms by which this drug exerts those effects are not yet fully elucidated, particularly in terms of its effect on redox status and inflammation. We aimed to investigate the effect of the antipsychotic, Fluanxol®, on redox status in vitro using BE(2)-M17 neuroblastoma cells, to simulate the target site, and CaCo2 gut epithelial carcinoma cells, to simulate the site of absorption, in the presence or absence of an inflammatory challenge (LPS). Cell viability (WST-1) validated the prescribed doses of Fluanxol® in our cellular models. Oxidant production (H2O2 assay kit), oxidative damage (TBARS (MDA) assay) and antioxidant capacity (TEAC) were assessed to probe the drug’s effect on redox status. Further investigation in vivo in zebrafish was used to assess effect of Fluanxol® on redox at whole organism complexity. After confirming non-toxicity of treatment doses in vivo, zebrafish were subjected to induced seizures using the pentylenetetrazole (PTZ) model, to determine therapeutic dose of Fluanxol® treatment in zebrafish. Activity monitoring was performed using a Daniovision activity tracker and Ethovision software. Optimal therapeutic dose of Fluanxol® treatment was assessed in terms of potential effects on redox status in zebrafish larvae at 4 days post-fertilisation (dpf), using the fluorescent ROS marker CM-H2DCFDA and live organism microscopy. No detrimental effects of Fluanxol® were observed in vitro, in terms of redox status. Dosage adjusted for bioavailability, confirmed that Fluanxol® does not display mitochondrial toxicity at the prescribed doses (3 mg/day to 12 mg/day), but mitochondrial toxicity was observed at an overdose concentration equivalent to 30 mg/day (p<0.0001). In the zebrafish model of psychosis, potential GABAergic effects of Fluanxol® was observed (p<0.0001). In addition, a novel finding was an antioxidant effect of Fluanxol®, as illustrated by reduced ROS (fluorescent intensity (p<0.01) and fluorescent area (p<0.05)) in 5 dpf zebrafish larvae. We conclude that Fluanxol® exhibited in vitro mitochondrial toxicity only at a dose equivalent to human overdose concentration, but that little to no toxicity is present within the prescribed doses. In line with this in vitro data, doses of Fluanxol® showing maximal antipsychotic effect in a zebrafish larval model, also reduced ROS levels, suggesting its therapeutic effect to include a positive outcome in terms of redox status. Finally, the observed antipsychotic effect of Fluanxol® in the PTZ model in zebrafish additionally suggest GABAergic modulation as a potential additional mechanism of action of this drug. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Oksidatiewe stress word geïmpliseer in skisofrenie patologie, met ingekorte teen-oksidant meganismes in pasiënte. Die modulerende rol van oksidatiewe stress op dieaktiwiteit van NMDA reseptore on GABA interneurone wat neurologiese seinoordrag beïnvloed, en lei sodoende na hiperdopaminergiese wanfunksie (direk geassosieer met siekte simptome), mikrogliale aktevering en ‘n pro-inflammatoriese skuif, wat hierdie pasiënte meer vatbaar vir inflammatoriese ko-morbiditeite maak. Dit is daar belangrik om terapeutiese middels wat aan skisofrenie lyers voorgeskryf word, te ondersoek en hul effek op redoksstatus te bepaal. Flupentixol dihydrochloride (Fluanxol®) word aan skisofrenie pasiënte voorgeskryf en het bekende anti-psigotiese effekte, maar die meganismes waardeur hierdie middel sy effekte uitoefen, is nog nie heeltemal duidelik nie. In terme van sy effek op redoksstatus en inflammasie spesifiek, is geen inligting bekend nie. Ons het beoog om die effek van die anti-psigotiese middel Fluanxol®, op in vitro redoksstatus te bepaal. Om hierdie doel te bereik, is BE(2)-M17 neuroblastoomselle, om die teikenwerf voor te stel, en CaCo2 kolonepiteelkarsinoomselle, om die absorpsieplek voor te stel, in die teenwoordigheid of afwesigheid van 'n inflammatoriese uitdaging (LPS). Sel lewensvatbaarheid (WST-1) het die voorgeskrewe dosisse Fluanxol® in ons sellulêre modelle gevalideer. Oksidatiewe stres (H2O2), oksidatiewe skade (TBARS (MDA) toets) en teen-oksidant kapasiteit (TEAC) is bepaal om die effek op die redoksstatus te ondersoek. Verdere ondersoek in vivo in sebravisse is gebruik om die effek van Fluanxol® op redoks by die hele organisme se kompleksiteit te bepaal. Na die bevestiging van nie-toksiese doserings in vivo, is sebravisse aan eksperimentele psigose in die pentileentetrasol (PTZ) model blootgestel, om terapeutiese dosis te bepaal van Fluanxol® behandeling in sebravisse. Aktiwiteit is met ‘n Daniovision aktiwiteitspoorder en Ethovision sagteware gemeet. Optimale terapeutiese doserings van Fluanxol® is ook in terme van die effek op redoksstatus in zebravislarwes teen 4 dae na bevrugting (dnb), gemeet, deur gebruik te maak van die RSS merker CM-H2DCFDA en lewende organisme mikroskopie. Geen nadelige effekte is in vitro vir Fluanxol® waargeneem in terme van redoksstatus nie. Nadat dosis aangepas is vir biobeskikbaarheid, is vasgestel dat Fluanxol® nie mitokondriale vergiftiging by voorgeskrewe dosisse (3 mg/dag tot 12 mg/dag) tot gevolg gehad het nie, maar wel by ‘n oordosering gelykstaande aan 30 mg/dag (p<0.0001). In die zebravismodel van psigose is moontlike GABAergiese effekte van Fluanxol® gemeet (p<0.0001). ‘n Verdere nuwe bevinding was ‘n teen-oksidant effek van Fluanxol®, soos geïllustreer deur verlaagde RSS (fluoresensie intensiteit (p<0.01) en area van fluoresensie (p<0.05)) in 5 dnb zebravislarwes. Ons bevind dat Fluanxol® slegs in ‘n dosering gelykstaande aan menslike oordosering, in vitro mitokondriale vergiftiging veroorsaak, maar dat min of geen vergiftiging by doserings gelykstaande aan voorgeskrewe terapeutiese doserings voorkom nie. In lyn met hierdie in vitro data, het doserings vanStellenbosch University https://scholar.sun.ac.za vi Fluanxol® wat goeie terapeutiese effek in die zebravismodel van psigose gehad het, ook laer RSS vlakke tot gevolg gehad, wat aandui dat die terapeutiese effekte van hierdie middel ook positiewe effekte op redoksstatus insluit. Laastens suggereer die waargenome teen-psigotiese effekte van Fluanxol® in die PTZ model in zebravisse dat GABAergiese modulering ‘n moontlike addisionele meganisme van aksie van hierdie middel mag wees. | en_ZA |
| dc.description.version | Masters | |
| dc.format.extent | xxi, 115 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110467 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Schizophrenia -- Effect of drugs on | en_ZA |
| dc.subject | Oxidative stress -- Treatment | en_ZA |
| dc.subject | Redox status | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Schizophrenia: Effect of Fluanxol® treatment on redox status | en_ZA |
| dc.type | Thesis | en_ZA |