Effects of switching from a high-fat diet to a ketogenic diet on oxidative stress, nitrosative damage, and protein glycation in rat skin

Background Obesity is a chronic metabolic disease characterized by increased oxidative and nitrosative stress, as well as enhanced protein glycation, all of which adversely affect the skin. Although the ketogenic diet (KD) has been shown to modulate oxidative stress, its effects on skin health remain poorly understood. Therefore, the aim of this study was to evaluate the effects of replacing a high-fat diet (HFD) with the KD on oxidative and nitrosative stress, protein glycation, and extracellular matrix remodeling in rat skin. Methods Male Wistar rats were randomly divided into four groups (n=10): standard diet (SD, 14 weeks), SD+KD (8 weeks SD, 6 weeks KD), HFD+SD (8 weeks HFD, 6 weeks SD), and HFD+KD (8 weeks HFD, 6 weeks KD). Results Antioxidant concentration and activity did not differ significantly between groups, with the exception of superoxide dismutase (SOD) activity, which was higher in the HFD+SD group compared to the SD and SD+KD groups. The HFD+SD group exhibited higher concentrations of advanced oxidation protein products (AOPPs) compared to the SD group and advanced glycation end products (AGEs) compared to the SD+KD group, as well as increased kynurenine (KN) content compared to the SD and SD+KD groups. Increased levels of crossline-related fluorophores (CRO) were observed in the HFD+SD group compared to the SD+KD group. Matrix metalloproteinase (MMP) activity remained comparable across groups. Conclusion Replacing the HFD with the KD may exert beneficial effects on skin metabolism in obese rats. The effects of the KD on skin metabolism appear to be comparable to those of the SD. Further studies are needed to elucidate the effects of the KD on skin metabolism in the context of metabolic diseases.