Zhou Qiao, Jin Hui, Shi Naiqi, Gao Shumei, Wang Xiaoyu, Zhu Shunxing, Yan Meijuan
The Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Australia.
Ann Transl Med. 2021 Sep;9(17):1360. doi: 10.21037/atm-21-1951.
Pyrroloquinoline quinone (PQQ) is a redox cofactor that can participate in a variety of physiological and biochemical processes, such as anti-inflammatory, cytoprotection, anti-aging, and anti-apoptosis. PQQ plays an important protective role in the central nervous system (CNS). However, the effects of PQQ on astrocytes of the CNS and spinal cord injury (SCI) of rats is still unclear. The present study investigates the role of PQQ in inflammation, apoptosis, and autophagy after SCI in rats. And the effect of PQQ on lipopolysaccharide (LPS)-induced apoptosis and inflammation of astrocytes , to explore the neuroprotective mechanism of PQQ.
Sixty specific pathogen free (SPF) SD male rats (200-250 g) were randomly divided into Normal group, Sham group, SCI group, and SCI + PQQ group, with 15 rats in each group. BBB score, HE staining, Nissl staining, Western blot, immunofluorescence, and other methods were used for detection.
Our results showed that PQQ could upregulate BBB score in SCI rats. In the second place, PQQ can increase the number and improve the morphology of neurons after SCI. The expression of IL-1β, TNF-α, IL-6 was significantly decreased after PQQ treatment. And then, the ratio of B-cell lymphoma-2 (Bcl-2)/Bcl-2 associated X protein (Bax) increased significantly, and the positive signal of NeuN increased obviously after PQQ treatment. There are a large number of co-localizations between Bcl-2 and NeuN. Meanwhile, PQQ could down-regulate the expression of Active-Caspase3, and PQQ treatment could reverse the transfer of Active-Caspase3/Caspase3 from the cytoplasm to the nucleus in neurons and astrocytes after SCI. At the same time, PQQ had no significant effect on the LC3b/a ratio. PQQ could decrease the LAMP2 expression in spinal cord after injury. The expression level of phospho-Akt (p-AKT) increased after SCI and decreased after PQQ treatment. In primary astrocytes, LPS could induce the expression levels of IL-1β, TNF-α, and IL-6, and which were inhibited by PQQ treatment at 12 hours. After treatment with LPS, the expression level of Active-Caspase3 increased, which could be reversed by PQQ treatment for 24 h.
These results suggest that PQQ can ameliorate the motor function of hind limbs and the pathological changes of neurons and injured spinal cord after SCI, down-regulate the expressions of IL-1β, TNF-α, and IL-6, inhibit apoptosis after SCI, and inhibit LPS-induced apoptosis and inflammation of astrocytes.
吡咯喹啉醌（PQQ）是一种氧化还原辅助因子，可参与多种生理和生化过程，如抗炎、细胞保护、抗衰老和抗凋亡。PQQ在中枢神经系统（CNS）中发挥重要的保护作用。然而，PQQ对中枢神经系统星形胶质细胞和大鼠脊髓损伤（SCI）的影响仍不清楚。本研究探讨PQQ在大鼠脊髓损伤后炎症、凋亡和自噬中的作用。以及PQQ对脂多糖（LPS）诱导的星形胶质细胞凋亡和炎症的影响，以探讨PQQ的神经保护机制。
将60只特定病原体无（SPF）级SD雄性大鼠（200 - 250 g）随机分为正常组、假手术组、脊髓损伤组和脊髓损伤+PQQ组，每组15只。采用BBB评分、HE染色、尼氏染色、蛋白质免疫印迹法、免疫荧光等方法进行检测。
我们的结果表明，PQQ可上调脊髓损伤大鼠的BBB评分。其次，PQQ可增加脊髓损伤后神经元的数量并改善其形态。PQQ处理后，IL-1β、TNF-α、IL-6的表达显著降低。然后PQQ处理后，B细胞淋巴瘤-2（Bcl-2）/Bcl-2相关X蛋白（Bax）的比值显著增加，NeuN的阳性信号明显增强。Bcl-2和NeuN之间存在大量共定位。同时，PQQ可下调活化半胱天冬酶3（Active-Caspase3）的表达，PQQ处理可逆转脊髓损伤后神经元和星形胶质细胞中Active-Caspase3/Caspase3从细胞质向细胞核的转移。同时，PQQ对LC3b/a比值无显著影响。PQQ可降低损伤后脊髓中溶酶体相关膜蛋白2（LAMP2）的表达。脊髓损伤后磷酸化蛋白激酶B（p-AKT）的表达水平升高，PQQ处理后降低。在原代星形胶质细胞中，LPS可诱导IL-1β、TNF-α和IL-6的表达水平升高，PQQ处理12小时可抑制这些表达。LPS处理后，Active-Caspase3的表达水平升高，PQQ处理24小时可使其逆转。
这些结果表明，PQQ可改善脊髓损伤后后肢的运动功能以及神经元和损伤脊髓的病理变化，下调IL-1β、TNF-α和IL-6的表达，抑制脊髓损伤后的凋亡，并抑制LPS诱导的星形胶质细胞凋亡和炎症。
