The kynurenine pathway (KP) is gaining attention in several clinical fields. Recent studies show that physical exercise offers a therapeutic way to improve ratios of neurotoxic to neuroprotective KP metabolites. Antioxidant supplementation can blunt beneficial responses to physical exercise. We here studied the effects of endurance training in the form of sprint interval training (SIT; three sessions of 4–6 × 30 s cycling sprints per week for three weeks) in elderly (~65 years) men exposed to either placebo (n = 9) or the antioxidants vitamin C (1 g/day) and E (235 mg/day) (n = 11). Blood samples and muscle biopsies were taken under resting conditions in association with the first (untrained state) and last (trained state) SIT sessions. In the placebo group, the blood plasma level of the neurotoxic quinolinic acid was lower (~30%) and the neuroprotective kynurenic acid to quinolinic acid ratio was higher (~50%) in the trained than in the untrained state. Moreover, muscle biopsies showed a training-induced increase in kynurenine aminotransferase (KAT) III in the placebo group. All these training effects were absent in the vitamin-treated group. In conclusion, KP metabolism was shifted towards neuroprotection after three weeks of SIT in elderly men and this shift was blocked by antioxidant treatment.

中文翻译：

---

维生素 C 和 E 治疗可阻断由三周冲刺间隔训练引发的犬尿氨酸代谢变化。

犬尿氨酸途径 (KP) 在多个临床领域受到关注。最近的研究表明，体育锻炼提供了一种治疗方法来提高神经毒性与神经保护性 KP 代谢物的比例。补充抗氧化剂可以减弱对体育锻炼的有益反应。我们在这里研究了以冲刺间歇训练（SIT；每周 3 次 4-6 × 30 秒的自行车冲刺，持续三周）形式对暴露于安慰剂的老年（~65 岁）男性（n = 9) 或抗氧化剂维生素 C（1 克/天）和 E（235 毫克/天）（n= 11）。血液样本和肌肉活检在休息条件下与第一次（未受训状态）和最后一次（受训状态）SIT 会话相关联。在安慰剂组中，受过训练的神经毒性喹啉酸的血浆水平较低 (~30%)，神经保护性犬尿酸与喹啉酸的比例高于未经训练的状态 (~50%)。此外，肌肉活检显示安慰剂组犬尿氨酸转氨酶 (KAT) III 由训练引起的增加。维生素治疗组不存在所有这些训练效果。总之，在老年男性 SIT 3 周后，KP 代谢转向神经保护，这种转变被抗氧化剂治疗阻止。