Department of Medical Parasitology and Mycology, Tehran University of Medical Sciences, Tehran, Iran.
Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Int J Nanomedicine. 2018 Mar 8;13:1341-1351. doi: 10.2147/IJN.S158736. eCollection 2018.
Natural polysaccharides such as chitosan (CS) are widely used as antimicrobial agents. In recent years, and considering that CS has a strong antimicrobial potential, interest has been focused on antimicrobial activity of chitosan nanoparticles (CS NPs). The main factors affecting the antibacterial activity of chitosan include molecular weight (MW) and concentration. In this regard, the aim of this study was to produce various MWs and concentrations of CS NPs, through the ionic gelation method, and investigate their potential anti-parasitic activity against tachyzoites of RH strain.
The MWs and degree of deacetylation of the CS were characterized using viscometric and acid-base titration methods, respectively. The efficacy of various MWs and concentrations of NPs was assessed by performing in vitro experiments for tachyzoites of RH strain, such as MTT assay, scanning electron microscopy, bioassay in mice and PCR. In vivo experiment was carried out in BALB/c mice which were inoculated with tachyzoites of RH strain and treated with various MWs of CS NPs.
The results of in vitro and in vivo experiments revealed that anti- activity strengthened as the CS NPs concentration increased and the MW decreased. In vitro experiment showed 100% mortality of tachyzoites at 500 and 1,000 ppm concentrations of low molecular weight (LMW) CS NPs after 180 min and at 2,000 ppm after 120 min. Furthermore, a 100% mortality of tachyzoites was observed at 1,000 and 2,000 ppm concentrations of medium molecular weight (MMW) CS NPs and at 2,000 ppm concentration of high molecular weight (HMW) CS NPs after 180 min. Growth inhibition rates of tachyzoites in peritoneal exudates of mice receiving low, medium and high MWs of CS NPs were found to be 86%, 84% and 79% respectively, compared to those of mice in sulfadiazine treatment group (positive control).
Various MWs of CS NPs exhibited great anti- efficiency against tachyzoites of RH strain, with the greatest efficacy shown by LMW CS NPs in both experiments. It seems that CS NPs can be used as an alternative natural medicine in the treatment of toxoplasmosis.
天然多糖如壳聚糖（CS）被广泛用作抗菌剂。近年来，鉴于 CS 具有很强的抗菌潜力，人们对壳聚糖纳米粒子（CS NPs）的抗菌活性产生了兴趣。影响壳聚糖抗菌活性的主要因素包括分子量（MW）和浓度。在这方面，本研究的目的是通过离子凝胶法制备不同 MW 和浓度的 CS NPs，并研究其对 RH 株速殖子的潜在抗寄生虫活性。
使用粘度计和酸碱滴定法分别对 CS 的 MW 和脱乙酰度进行了表征。通过对 RH 株速殖子进行体外实验，如 MTT 测定、扫描电子显微镜、小鼠生物测定和 PCR 等，评估了不同 MW 和浓度的 NPs 的疗效。在 BALB/c 小鼠中进行了体内实验，这些小鼠接种了 RH 株速殖子，并接受了不同 MW 的 CS NPs 治疗。
体内外实验结果表明，随着 CS NPs 浓度的增加和 MW 的降低，抗活性增强。体外实验结果表明，低分子量（LMW）CS NPs 在 500 和 1000 ppm 浓度下，180 分钟后速殖子的死亡率达到 100%，2000 ppm 浓度下 120 分钟后死亡率达到 100%。此外，中分子量（MMW）CS NPs 在 1000 和 2000 ppm 浓度下，HMW CS NPs 在 2000 ppm 浓度下，180 分钟后速殖子的死亡率均达到 100%。与磺胺嘧啶治疗组（阳性对照）相比，接受低、中、高 MW CS NPs 的小鼠腹腔渗出液中速殖子的生长抑制率分别为 86%、84%和 79%。
不同 MW 的 CS NPs 对 RH 株速殖子表现出很强的抗效率，在两项实验中，LMW CS NPs 的效果最佳。CS NPs 似乎可以作为治疗弓形虫病的替代天然药物。
