Exploring Immediate Photon Effects From 635 nm Light on Mitochondrial Bioenergetics.

Visible light primarily targets mitochondria at the cellular level, but photon interaction mechanisms are still not fully understood. This study examined the in vitro impacts of 635 nm laser irradiation using mitochondria isolated from mouse liver. Mitochondria samples were irradiated for 330 s inside the respirometer chamber, with delivered powers ranging from 100 to 800 mW, corresponding to power densities ranging from 31.6 to 211.7 mW/cm² inside the chamber. Analysis of real-time oxygen consumption showed an elevated proton leak during ATP synthase inhibition at 800 mW (211.7 mW/cm², 69.9 J/cm²), suggesting enhanced permeability of the mitochondrial inner membrane. Under different experimental conditions, post-irradiation analysis revealed increased basal respiration with 400 mW (129.1 mW/cm², 42.6 J/cm²) and 800 mW, along with increased susceptibility to Ca²⁺-triggered mitochondrial swelling. The investigation of mitochondrial bioenergetics demonstrated that red light induces transient and localized effects, highlighting the complexities of cellular and mitochondrial photostimulation mechanisms.