The 1-Week and 8-Month Effects of a Ketogenic Diet or Ketone Salt Supplementation on Multi-Organ Markers of Oxidative Stress and Mitochondrial Function in Rats

Abstract

We determined the short- and long-term effects of a ketogenic diet (KD) or ketone salt (KS) supplementation on multi-organ oxidative stress and mitochondrial markers. For short-term feedings, 4 month-old male rats were provided isocaloric amounts of KD (n = 10), standard chow (SC) (n = 10) or SC + KS (~1.2 g/day, n = 10). For long-term feedings, 4 month-old male rats were provided KD (n = 8), SC (n = 7) or SC + KS (n = 7) for 8 months and rotarod tested every 2 months. Blood, brain (whole cortex), liver and gastrocnemius muscle were harvested from all rats for biochemical analyses. Additionally, mitochondria from the brain, muscle and liver tissue of long-term-fed rats were analyzed for mitochondrial quantity (maximal citrate synthase activity), quality (state 3 and 4 respiration) and reactive oxygen species (ROS) assays. Liver antioxidant capacity trended higher in short-term KD- and SC + KS-fed versus SC-fed rats, and short-term KD-fed rats exhibited significantly greater serum ketones compared to SC + KS-fed rats indicating that the diet (not KS supplementation) induced ketonemia. In long term-fed rats: (a) serum ketones were significantly greater in KD- versus SC- and SC + KS-fed rats; (b) liver antioxidant capacity and glutathione peroxidase protein was significantly greater in KD- versus SC-fed rats, respectively, while liver protein carbonyls were lowest in KD-fed rats; and (c) gastrocnemius mitochondrial ROS production was significantly greater in KD-fed rats versus other groups, and this paralleled lower mitochondrial glutathione levels. Additionally, the gastrocnemius pyruvate-malate mitochondrial respiratory control ratio was significantly impaired in long-term KD-fed rats, and gastrocnemius mitochondrial quantity was lowest in these animals. Rotarod performance was greatest in KD-fed rats versus all other groups at 2, 4 and 8 months, although there was a significant age-related decline in performance existed in KD-fed rats which was not evident in the other two groups. In conclusion, short- and long-term KD improves select markers of liver oxidative stress compared to SC feeding, although long-term KD feeding may negatively affect skeletal muscle mitochondrial physiology.

β-Hydroxybutyrate Elicits Favorable Mitochondrial Changes in Skeletal Muscle

“…This is consistent with previous work [33] in which similar findings were found in the mixed gastrocnemius of rats fed a ketogenic diet for 8 weeks. Despite the reduction in citrate synthase activity, red quadriceps muscles from KETO-fed rats had increased respiration, perhaps evidence of a compensatory mechanism.…”

An 8-Week Ketogenic Low Carbohydrate, High Fat Diet Enhanced Exhaustive Exercise Capacity in Mice

“…Since there are abundant studies reporting ALT, AST, LDH and CK being closely correlated with exercise time, thus, this will not be elaborated about it here. In another animal study, short- and long-term KD-feeding improved several liver oxidative stress markers, showing that the anti-oxidative potential of KD may also enhance endurance exercise [ 58 ]. Muscular fat oxidation capacity may also play a key role during endurance exercise, and the mechanism of this needs further study [ 59 ].…”

Ketogenic diet increases mitochondria volume in the liver and skeletal muscle without altering oxidative stress markers in rats

“…The aforementioned study also demonstrated state 4 mitochondria respiration was decreased with calorie restriction in the brain, heart, and kidney tissues [18] . Additionally, our lab previously reported an increase in liver total antioxidant capacity and increased antioxidant glutathione peroxidase (GPX) liver protein levels after an 8-month long KD diet in rats [19] . In addition, Newman et al.…”