title: Irradiated cationic mesoporphyrin induces larger damage to isolated rat liver mitochondria than the anionic form.
abstract: The action of irradiated cationic Fe(III)TMPyP and anionic Fe(III)TPPS4 forms of mesoporphyrins on mitochondrial functions was investigated using experimental conditions that caused minimal effects on mitochondria in the dark. Treatment of mitochondria with 1 microM Fe(III)TMPyP for 2 min decreased the respiratory control by 3% in the dark and 28% after irradiation. Fe(III)TPPS4 (1 microM) had no significant effect on respiratory control under any of the above conditions. Both porphyrins increased the mitochondrial production of reactive oxygen species in the presence of Ca2+; however, the effect of Fe(III)TMPyP was significantly stronger. In both cases, this overproduction was associated with membrane lipid peroxidation. It was also observed that the association constant of Fe(III)TMPyP with mitochondria was 11 times higher than that of Fe(III)TPPS4. In conclusion, the damage to isolated mitochondria induced by Fe(III)TMPyP under illumination was larger than by Fe(III)TPPS4, probably because its cationic charge favors association with the mitochondrial membrane. This is supported by the decrease in the association constant of Fe(III)TMPyP with mitochondria in higher salt medium.
authors.affiliation: Laboratório de Bioenergética, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, São Paulo, Brazil.
authors.forename: Natalia M
authors.initials: NM
authors.lastname: Inada
authors.forename: André R
authors.initials: AR
authors.lastname: da Silva
authors.forename: Renato A
authors.initials: RA
authors.lastname: Jorge
authors.forename: Jiri
authors.initials: J
authors.lastname: Borecký
authors.forename: Anibal E
authors.initials: AE
authors.lastname: Vercesi
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D008027:Light; D015227:Lipid Peroxidation / Q000187:drug effects; D008652:Mesoporphyrins / Q000494:pharmacology / Q000528:radiation effects* / Q000633:toxicity; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000096:biosynthesis; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D017319:Photosensitizing Agents / Q000494:pharmacology / Q000528:radiation effects* / Q000633:toxicity; D011166:Porphyrins / Q000494:pharmacology / Q000528:radiation effects* / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D008652:Mesoporphyrins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D017319:Photosensitizing Agents; D011166:Porphyrins; D017382:Reactive Oxygen Species; C092399:meso-tetrakis(1-methyl-4-pyridiniumyl)porphyrin; C016136:tetraphenylporphine sulfonate