Studija citotoksičnih učinaka polikloriranih bifenila

doctoral thesis

• Title (english): The study of polychlorinated biphenyls' cytotoxic effects
• Author: Teuta Murati
• Mentor: Branimir Šimić (mentor)
• Committee member: Ivana Kmetič (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2015-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology
• Universal decimal classification (UDC): 577 - Biochemistry. Molecular biology. Biophysics

Abstract

Poliklorirani bifenili (polychlorinated biphenyls; PCB) su visoko perzistentni organski zagađivači okoliša, identificirani kao potencijalni endokrini modulatori sa sposobnošću negativnog učinka na ljudsko zdravlje. U ovom radu ispitani su i uspoređeni specifični intracelularni toksični učinci dva odabrana, prema stupnju klorinacije, planarnosti i aktivnosti različita PCB kongenera - planarnog, „dioksinu sličnog“ tetraklorbifenila PCB 77 i neplanarnog, ortho-supstituiranog heksaklorbifenila PCB 153, primjenom in vitro modela stanica ovarija kineskog hrčka CHO-K1 (Chinese Hamster Ovary). Planarni PCB 77 (10 – 100 μM) pokazao je jače toksične učinke u odnosu na neplanarni PCB 153 (10 – 100 μM), što se može dovesti u vezu s vremenski ranijim te jačim učinkom na proliferaciju i vijabilnost stanica (usporedbom IC50 vrijednosti, doza pri kojima je određena 50 %-tna inhibicija vijabilnosti stanica, utvrđenih metodama Trypan Blue, Neutral Red, Kenacid Blue i MTT), većim promjenama u progresiji staničnog ciklusa te jače induciranim oksidacijskim stresom (usporedbom utjecaja na lipidnu peroksidaciju i stvaranje reaktivnih kisikovih vrsta). Gubitak stanične vijabilnosti, kao posljedica izloženosti stanica toksičnijem kongeneru PCB 77, u najvećem dijelu događa se zbog indukcije apoptoze, prije nego nekroze (potvrđeno fluorescentnom mikroskopijom i mjerenjem aktivnosti izvršne kaspaze 3). Antioksidans vitamin E (50 – 150 μM), pokazao je veći protektivni učinak na s neplanarnim PCB-em inducirana oštećenja, nego na oštećenja nastala tretmanom s PCB 77, kako na smanjenje oksidacijskog stresa tako i na poboljšanu proliferaciju i vijabilnost stanica.

Abstract (english)

Polychlorinated biphenyls (PCB) are highly persistent environmental pollutants, identified as potential endocrine disruptors with the ability of harmful effects on human health. In this study specific intracellular toxic effects of two selected, according to the degree of chlorination, planarity and activities different PCB congeners - planar, "dioxin-like" tetrachlorbiphenyl PCB 77 and nonplanar, ortho-substituted hexachlorbiphenyl PCB 153, were examined and compared, using in vitro Chinese Hamster Ovary (CHO-K1) cell model. Planar PCB 77 (10-100 μM) exhibited stronger toxic effect in comparison to non-planar PCB 153 (10-100 μM), which can be correlated with an earlier and stronger effect on the proliferation and cell viability (comparing IC50 values, concentrations which are required for 50 % inhibition of cell viability, determined with Trypan Blue, Neutral Red, Kenacid Blue and MTT methods), significant changes in cell-cycle progression and more induced oxidative stress (comparing the effects on lipid peroxidation and production of reactive oxygen species). The loss of cell viability, as a result of the exposure of cells to more toxic PCB 77, for the most part occurs due to induction of apoptosis, rather than necrosis (confirmed by fluorescent microscopy and by measuring the activity of the executive caspase 3). In order to reduce oxidative stress and enhance proliferation and cell viability, antioxidant vitamin E (50-150 μM), showed higher protective effect with the non-planar PCB induced cell damages, than when the cells were exposed to PCB 77.

• Keywords: PCB 77; PCB 153; CHO-K1 stanična linija; citotoksičnost; stanični ciklus; stanična smrt; oksidacijski stres; vitamin E
• Keywords (english): PCB 77; PCB 153; CHO-K1 cell line; cytotoxicity; cell cycle; cell death; oxidative stress; vitamin E
• Language: croatian
• URN:NBN: urn:nbn:hr:159:288257
• Promotion: 2015-09-27
• Study programme: Title: Postgraduate PhD Study in Biotechnology and Bioprocess Engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-17 11:49:09