The photodynamic and direct actions of methylene blue on mitochondrial energy metabolism: A balance of the useful and harmful effects of this photosensitizer.

The photodynamic and direct actions of methylene blue on mitochondrial energy metabolism: A balance of the useful and harmful effects of this photosensitizer. Free Radic Biol Med. 2020 Apr 18;: Authors: Klosowski EM, Lima de Souza BT, Mito MS, Constantin RP, Mantovanelli GC, Mewes JM, Veiga Bizerra PF, Moreira da Costa Menezes PV, Gilglioni EH, Utsunomiya KS, Marchiosi R, Dantas Dos Santos W, Filho OF, Caetano W, Cesar de Souza Pereira P, Gonçalves RS, Constantin J, Ishii-Iwamoto EL, Constantin RP Abstract According to the literature, methylene blue (MB) is a photosensitizer (PS) with a high affinity for mitochondria. Therefore, several studies have explored this feature to evaluate its photodynamic effects on the mitochondrial apoptotic pathway under normoxic conditions. We are aware only of limited reports regarding MB's photodynamic effects on mitochondrial energy metabolism, especially under hypoxic conditions. Thus, the purposes of this study were to determine the direct and photodynamic acute effects of MB on the energy metabolism of rat liver mitochondria under hypoxic conditions and its direct acute effects on several parameters linked to energy metabolism in the isolated perfused rat liver. MB presented a high affinity for mitochondria, irrespective of photostimulation or proton gradient formation. Upon photostimulation, MB demonstrated high in vitro oxidizing species generation ability. Consequently, MB damaged the mitocho...
Source: Free Radical Biology and Medicine - Category: Biology Authors: Tags: Free Radic Biol Med Source Type: research