Photobiology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Campus, Lucknow 226001, Uttar Pradesh, India.
Photobiology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Pineal Research Lab, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India.
Int J Pharm. 2018 Apr 25;541(1-2):173-187. doi: 10.1016/j.ijpharm.2018.02.028. Epub 2018 Feb 17.
Sparfloxacin (SPFX) is a broad spectrum antibiotic which inhibits bacterial DNA gyrase enzyme activity. However, photodegradation in the presence of UVA limits its antibacterial activity and induces phototoxicity. Thus, to encounter this problem, we have developed poly d,l-lactic-co-glycolic acid (PLGA) loaded SPFX nanoparticles. Here, we have performed a comparative antibacterial activity of SPFX and its nanoparticles (NPs) through molecular docking and plate sensitivity assay. Under environmental UVA exposure, photoexcited SPFX significantly generates ROS, DNA damage and mitochondrial mediated cell death in comparison to PLGA-SPFX-NPs (nano SPFX) in human skin cell line (HaCaT). In presence of UVA, bulk SPFX induced cell cycle arrest with appearance of sub-G1 peak showing apoptosis while nano SPFX did not show any change. SPFX triggered apoptosis via alteration in membrane integrity of mitochondria and lysosome in comparison to PLGA-SPFX-NPs. Involvement of mitochondrial mediated cell death was confirmed by down-regulation of anti-apoptotic Bcl-2 and procaspase-3 and upregulation of pro-apoptotic Bax, cytochrome-c and caspase-3 proteins expression. Specific caspase inhibitor, Z-VAD-FMK showed involvement of caspase cascade pathway in apoptosis. Our finding suggests that controlled release of SPFX from PLGA-SPFX-NPs can reduce its side effects and enhance its antibacterial activity. Thus, nanotization of fluoroquinolones will be a significant step to reduce the problem of resistance and phototoxicity of this group.
司帕沙星（SPFX）是一种广谱抗生素，可抑制细菌 DNA 回旋酶的活性。然而，UVA 存在下的光降解会限制其抗菌活性并诱导光毒性。因此，为了解决这个问题，我们已经开发了聚丙交酯-乙交酯（PLGA）负载司帕沙星纳米粒。在这里，我们通过分子对接和平板敏感性测定比较了司帕沙星及其纳米粒（NPs）的抗菌活性。在环境 UVA 暴露下，与 PLGA-SPFX-NPs（纳米 SPFX）相比，光激发的司帕沙星在人皮肤细胞系（HaCaT）中显著产生 ROS、DNA 损伤和线粒体介导的细胞死亡。在 UVA 存在下， bulk SPFX 诱导细胞周期停滞，出现亚 G1 峰，表现出凋亡，而纳米 SPFX 则没有任何变化。与 PLGA-SPFX-NPs 相比，司帕沙星通过改变线粒体和溶酶体的膜完整性触发凋亡。通过下调抗凋亡 Bcl-2 和 procaspase-3 以及上调促凋亡 Bax、细胞色素 c 和 caspase-3 蛋白表达，证实了线粒体介导的细胞死亡的参与。特异性半胱氨酸蛋白酶抑制剂 Z-VAD-FMK 表明凋亡涉及半胱氨酸蛋白酶级联途径。我们的研究结果表明，从 PLGA-SPFX-NPs 中控制释放 SPFX 可以减少其副作用并增强其抗菌活性。因此，氟喹诺酮类药物的纳米化将是减少该类药物耐药性和光毒性问题的重要步骤。
