该研究采用超声波辅助热水浸提桑黄多糖，通过Nrf2信号通路探讨其对运动疲劳小鼠肝损伤的保护作用。结果表明，桑黄多糖提取得率为7.64%，纯化效率为23%。与运动疲劳模型组相比，桑黄多糖显著降低了小鼠的肝脏系数，低、中、高浓度组力竭游泳时间分别显著提高了15.58%、34.69%、53.06%；相比安静对照组，模型组肝脏内SOD、CAT、GSH-Px活性显著降低，MDA含量显著升高，血清炎症因子（TNF-α、IL-1β、IL-6）水平和ALT、AST活性均显著升高，与模型组相比，低、中、高浓度组肝脏抗氧化酶活性显著升高，MDA含量显著降低，其中高浓度组小鼠血清TNF-α、IL-1β、IL-6水平分别显著降低了50.54%、50.51%、46.21%，ALT、AST活性分别显著降低了33.30%、34.57%。模型组Nrf 2、HO-1、NQO1 mRNA表达水平较安静对照组显著降低，Keap1 mRNA表达水平显著升高，补充多糖后，低、中、高浓度组Nrf 2、HO-1、NQO1 mRNA表达水平显著升高，Keap1 mRNA表达水平显著降低。提示桑黄多糖通过激活肝脏Nrf2 信号通路，起到提高运动疲劳小鼠肝脏的抗氧化和降低炎症因子的作用，从而减轻小鼠的肝损伤。

Ultrasound-assisted hot water extraction was utilized to obtain Phellinus linteus polysaccharides (PLPs), and its protective effect on liver injury in exercise-induced fatigue mice was investigated through modulation of the Nrf2 signaling pathway. Results showed a PLP extraction yield of 7.64%, with a purification efficiency of 23%. PLP administration led to a significant reduction in the liver coefficient of mice compared to the exercise-induced fatigue model group. Moreover, it increased swimming endurance times of the low-, medium-and high-dose groups by 15.58%, 34.69% and 53.06%, respectively. Compared to the sedentary control group, the model group exhibited significantly diminished activities of antioxidative enzymes in the liver, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx), alongside increased malondialdehyde (MDA) content; serum inflammatory factors such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6); and alanine transaminase (ALT) and aspartate transaminase (AST) activities. Conversely, the low-, medium-and high-dose groups demonstrated elevated antioxidant enzymes activity in the liver and reduced MDA content in comparison to the model group. Notably, the high-dose group exhibited significant reductions in serum TNF-α, IL-1β, and IL-6 levels by 50.54%, 50.51%, and 46.21%, respectively, alongside ALT and AST activities by 33.30% and 34.57%, respectively. Moreover, mRNA expression levels of Nrf 2, HO-1, and NQO1 were significantly lower in the model group compared to the sedentary group, while Keap1 mRNA expression was significantly higher. Post-PLP supplementation, mRNA expression levels of Nrf 2, HO-1 and NQO1 significantly increased in the low-, medium-and highdose groups, while Keap1 mRNA expression significantly decreased. These findings collectively suggest that PLPs enhance hepatic antioxidant capacity and reduce inflammatory factors in exercise-induced fatigue mice by activating the hepatic Nrf2 signaling pathway, thereby mitigating liver injury.

国家自然科学基金面上项目（81773384）