UC Davis

Changes in mitochondrial dynamics are often associated with dietary patterns, medical treatments, xenobiotics, and diseases. Toxic exposures to hydrogen sulfide (H₂S) harm mitochondria by inhibiting Complex IV and via other mechanisms. However, changes in mitochondrial dynamics, including morphology following acute exposure to H₂S, are not yet fully understood. This study followed mitochondrial morphology changes over time after a single acute LCt₅₀ dose of H₂S by examining electron microscopy thalami images of surviving mice. Our findings revealed that within the initial 48 h after H₂S exposure, mitochondrial morphology was impaired by H₂S, supported by the disruption and scarcity of the cristae, which are required to enhance the surface area for ATP production. At the 72-h mark point, a spectrum of morphological cellular changes was observed, and the disordered mitochondrial network, accompanied by the probable disruption of mitophagy, was tied to changes in mitochondrial shape. In summary, this study sheds light on how acute exposure to high levels of H₂S triggers alterations in mitochondrial shape and structure as early as 24 h that become more evident at 72 h post-exposure. These findings underscore the impact of H₂S on mitochondrial function and overall cellular health.