Pyrroloquinoline quinone (PQQ) producing Escherichia coli Nissle 1917 (EcN) alleviates age associated oxidative stress and hyperlipidemia, and improves mitochondrial function in ageing rats
Background: Ageing involves oxidative stress mediated by Reactive Oxygen Species (ROS) and mitochondrial dysfunction. The present work demonstrates the protective effect of PQQ producing EcN against rotenone induced mitochondrial oxidative stress and consequence of mitochondrial and cellular dysfunction in naturally ageing rat model. PQQ is a potent antioxidant molecule also known to stimulate mitochondrial biogenesis and function in mammals.
背景: 衰老涉及由活性氧化应激介导的活性氧类和线粒体功能障碍。本研究证实了 PQQ 产生的 EcN 对鱼藤酮诱导的线粒体氧化应激的保护作用，以及在自然衰老大鼠模型中线粒体和细胞功能障碍的后果。PQQ 是一种有效的抗氧化分子，也被认为可以刺激哺乳动物的线粒体生物合成和功能。
Methods: Firstly, adult rats (16-18 weeks old) were treated with rotenone (2.5 mg/kg body weight; i.p.) daily for 28 days along with PQQ (10 mg/kg diet, daily) and modified probiotic EcN strains (10(8) CFU twice weekly). Secondly, ageing rats (48-50 weeks old) were gavaged with probiotic EcN strains (10(8)CFU twice weekly) and PQQ (10 mg/kg diet, daily) for 8 months.
方法: 首先用鱼藤酮(2.5 mg/kg 体重，i.p.)连续28d，PQQ (10mg/kg 日粮，每日)和改良益生菌 EcN (10(8) CFU，每周2次)处理成年大鼠。其次，用益生菌 EcN (10(8) CFU)和 PQQ (10mg/kg 日粮，每日一次)分别喂养衰老大鼠(48-50周龄)8个月。
Results: PQQ producing EcN-5 treatment prevented rotenone induced hepatic oxidative stress and mitochondrial damage in rats as assessed by reduced lipid peroxidation (29%), elevated glutathione (GSH) content (43%), increased catalase (52%) and superoxide dismutase (52%) activities when compared to only rotenone treatment. Moreover, increased hepatic mitochondrial content (41%), peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α) mRNA (25%) and mitochondrial Superoxide Dismutase (Mit-SOD) activity (94%) were also observed in EcN-5 treated rats. Rotenone treated rats did not exhibit gain in body weight, whereas rats co-treated with EcN-5 showed significant restoration in body weight gain. Furthermore, weekly administration of EcN-5 to naturally ageing rats for eight months resulted in significant reduction of oxidative stress in hepatic and colonic tissues (assessed by lipid peroxidation, GSH content and catalase and SOD enzyme activities) along with increase in hepatic mitochondrial enzyme activities (Mit-SOD and succinate dehydrogenase) and biogenesis, when compared to untreated rats. Additionally, these rats also exhibited reduced expression of fatty acid synthase (50%) and increased expression of acyl coenzyme oxidase (225%) genes in liver in contrast to untreated rats resulting in lowered triglyceride (13% & 13.5%) and cholesterol (21% & 27%) levels in plasma and liver, respectively. Increased levels of butyrate (93%), propionate (45%) and acetate (18%) were also found in colonic content of these rats. PQQ administered daily (supplemented in diet) exhibited more or less similar effect as weekly gavaged EcN-5 in both the experiments, which substantiate that these effects are mediated by PQQ.
结果: 与单用鱼藤酮相比，PQQ 产生的 EcN-5能够减少鱼藤酮诱导的大鼠肝脏氧化应激和线粒体损伤，脂质过氧化(29%)、谷胱甘肽(GSH)含量升高(43%)、过氧化氢酶(52%)和超氧化物歧化酶(52%)活性增加。此外，EcN-5大鼠肝脏线粒体含量(41%)、过氧化物酶体增殖物激活受体 γ 辅激活因子1-α (pgc-1) mRNA (25%)和线粒体超氧化物歧化酶(Mit-SOD)活性(94%)增加。鱼藤酮处理的大鼠体重没有增加，而与 EcN-5共处理的大鼠体重增加显著恢复。此外，每周给自然衰老的大鼠注射 EcN-5达8个月后，与未注射 EcN-5的大鼠相比，肝脏和结肠组织中的氧化应激显著减少(通过脂质过氧化、 GSH 含量、过氧化氢酶和超氧化物歧化酶活性) ，肝脏线粒体酶活性(mit-SOD 和琥珀酸脱氢酶)和生物发生增加。此外，与未经处理的大鼠相比，这些大鼠还表现出脂肪酸合酶基因表达减少(50%)和肝脏内酰基辅酶氧化酶基因表达增加(225%) ，导致血浆和肝脏中甘油三酯和胆固醇水平分别降低(13% 和13.5%)和(21% 和27%)。这些大鼠的结肠内容物中丁酸(93%)、丙酸(45%)和乙酸(18%)的含量也有所增加。PQQ 每日给药(日粮中添加)与每周给药 EcN-5的效果基本相同，证实这些效应是通过 PQQ 介导的。
Conclusion: These results suggest that genetically modified EcN-5 can be used as a nutritional supplement which can reduce age related oxidative stress and hyperlipidemia. Furthermore, it also rejuvenates healthy mitochondria by stimulating mitochondrial biogenesis and metabolism.
结论: 转基因 EcN-5可作为一种营养补充剂，降低年龄相关性氧化应激和高脂血症。此外，它还通过刺激线粒体的生物发生和新陈代谢，使健康的线粒体返老还童。