Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Beykoz, Istanbul, Turkey.
Graduate School of Engineering and Natural Sciences, Istanbul Medipol University, Beykoz, Istanbul, Turkey.
Int J Nanomedicine. 2020 Nov 20;15:9211-9229. doi: 10.2147/IJN.S272931. eCollection 2020.
Curcumin, a polyphenol isolated from the rhizomes of turmeric, holds great potential as a neuroprotective agent in addition to its anti-inflammatory and antioxidant characteristics. The poor bioavailability and low stability of curcumin are the greatest barriers to its clinical use. This study aims to investigate the neuroprotective effect of curcumin on axonal injury, by delivering the lipophilic polyphenol to a primary hippocampal neuron culture by means of a lipid-based drug delivery system, named emulsomes.
To study neuroregeneration ex vivo, an injury model was established through single-cell laser axotomy on hippocampal neurites. Upon treatment with curcumin-loaded emulsomes (CurcuEmulsomes), curcumin and CurcuEmulsome uptake into neurons was verified by three-dimensional Z-stack images acquired with confocal microscopy. Neuron survival after axonal injury was tracked by propidium iodide (PI) and Hoechst staining. Alterations in expression levels of physiological markers, such as anti-apoptotic marker Bcl2, apoptotic marker cleaved caspase 3, neuroprotective marker Wnt3a and the neuronal survival marker mTOR, were investigated by immunocytochemistry analyses.
The results indicated significant improvement in the survival rate of injured neurons upon CurcuEmulsome treatment. Bcl2 expression was significantly higher for injured neurons treated with curcumin or CurcuEmulsome. Reduction in caspase 3 expression was seen in both curcumin and CurcuEmulsome treatment, whereas there were no significant changes in Wnt3a and mTOR expression.
The established laser-axotomy model was proven as a reliable methodology to study neurodegenerative models ex vivo. CurcuEmulsomes delivered curcumin to primary hippocampal neurons successfully. Treated with CurcuEmulsomes, injured hippocampal neurons benefit from the neuroprotective effects of curcumin, exhibiting a higher survival rate and increased anti-apoptotic marker levels.
姜黄素是从姜黄根茎中分离得到的一种多酚，除了具有抗炎和抗氧化特性外，它还具有神经保护作用。姜黄素的生物利用度差和稳定性低是其临床应用的最大障碍。本研究旨在通过使用脂质药物递送系统（称为乳剂）将亲脂性多酚递送至原代海马神经元培养物，来研究姜黄素对轴突损伤的神经保护作用。
为了在体外研究神经再生，通过单细胞激光轴突切断术建立海马神经元突起的损伤模型。通过共聚焦显微镜获得的三维 Z 堆叠图像，验证了载姜黄素乳剂（CurcuEmulsomes）处理后姜黄素和 CurcuEmulsomes 进入神经元。用碘化丙啶（PI）和 Hoechst 染色跟踪轴突损伤后神经元的存活情况。通过免疫细胞化学分析研究生理标志物（如抗凋亡标志物 Bcl2、凋亡标志物 cleaved caspase 3、神经保护标志物 Wnt3a 和神经元存活标志物 mTOR）的表达水平变化。
结果表明，用 CurcuEmulsomes 处理后，损伤神经元的存活率显著提高。用姜黄素或 CurcuEmulsomes 处理的损伤神经元的 Bcl2 表达明显更高。姜黄素和 CurcuEmulsomes 处理均导致 caspase 3 表达减少，而 Wnt3a 和 mTOR 表达没有明显变化。
已建立的激光轴突切断模型被证明是研究体外神经退行性模型的可靠方法。乳剂成功地将姜黄素递送至原代海马神经元。用 CurcuEmulsomes 处理后，损伤的海马神经元受益于姜黄素的神经保护作用，表现出更高的存活率和增加的抗凋亡标志物水平。
