Transcriptomic responses of mitochondrial and immune pathways to chronic white-light exposure in the mouse retina

Excessive light exposure induces oxidative stress and structural damage in the neural retina, yet genome-wide transcriptional responses to different chronic light exposure regimens remain incompletely understood. We analyzed retinal transcriptomic alterations under two chronic white-light exposure regimens in C57BL/6J mice. Neural retinas were collected from mice exposed to white light for 8–24 h per week for 4 weeks and from non-light-exposed controls ( n = 6 each), and genome-wide expression profiling was performed using the Clariom D microarray. At the transcript level, only a small number of transcripts met stringent differential expression criteria, and no large-amplitude changes in protein-coding genes were observed. In contrast, gene set enrichment analysis revealed clear differences in pathway-level responses between the two light exposure regimens. The 8-hour exposure group exhibited strong negative enrichment of mitochondrial pathways, including mitochondrial translation, respiratory chain complex assembly, and oxidative phosphorylation, indicating mitochondrial metabolic suppression under the lower weekly light exposure regimen. By contrast, the 24-hour exposure group exhibited strong positive enrichment of immune-related pathways, including humoral and lymphocyte-mediated immune responses and cytokine signaling, indicating enhanced immune and inflammatory activation under the higher weekly light exposure regimen. These findings demonstrate that chronic white-light exposure elicits distinct retinal transcriptional responses under different weekly light exposure regimens, with mitochondrial suppression in the lower exposure regimen and immune activation in the higher exposure regimen.