Repeated Exposure to a Hair Bleaching Mixture Alters cGAS-STING Pathway Transcripts in Mice

Hair bleaching products commonly contain ammonia and hydrogen peroxide, chemicals capable of generating reactive oxygen species (ROS). However, their effects on innate immune signaling pathways associated with DNA damage remain poorly understood. We investigated whether repeated topical exposure to a bleaching mixture modulates the cGAS-STING pathway in C57BL/6 mice. Male and female mice were exposed weekly for 10 weeks to a commercial bleaching formulation containing 5.8% ammonia and 12% hydrogen peroxide. A subgroup received N-acetylcysteine (100 mg/kg), an antioxidant treatment, 1 h before each exposure. Gene expression of Cgas, Sting, and Tbk1 was assessed by RT-qPCR in spleen samples, and femoral bone marrow was examined histologically. Male mice exposed to the bleaching mixture showed significant upregulation of Cgas and Sting transcripts compared with N-acetylcysteine-treated animals, whereas Sting expression was also increased relative to controls. Histological evaluation identified clustered megakaryocytes with dysplastic features in two exposed males, whereas female mice showed no transcriptional or histological alterations. These findings suggest that repeated exposure to bleaching chemicals may promote oxidative stress-associated transcriptional changes in the cGAS-STING in a sex-dependent manner. Although additional mechanistic studies are warranted, these preliminary data support further investigation of transcriptional and functional responses involving innate immune DNA-sensing pathways following repeated exposure to hair-bleaching chemicals.