Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China.
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China.
Microb Pathog. 2021 May;154:104855. doi: 10.1016/j.micpath.2021.104855. Epub 2021 Mar 20.
Leptospirosis, caused by pathogenic Leptospira species, is an essential but neglected zoonosis. There are more than 300 serovars of pathogenic Leptospira, while inactivated bacteria offers only short-term serovar-specific protection. Leptospirosis treatment is mainly dependent on the use of antibiotics. However, the side effects of antibiotics and the risk of antibiotic resistance remain major problems. Thus, alternative agents which are fewer side effects on humans and efficient in leptospirosis would be welcome. Many studies have reported that polysaccharides could be used as immunostimulants in treating infection and cancer. In this study, we examined the protective effect of polysaccharides isolated from Iris against leptospirosis. To our knowledge, it is the first time to report Iris polysaccharides (IP) as an immunostimulant in treating infection. The results showed that IP treatment significantly increased the survival rate of hamsters challenged by a lethal dose of leptospires. Besides, the tissue injury and leptospiral load were reduced in IP-treated infection group compared with the untreated infection group at 4 days post-infection (p.i.). Intriguingly, IP treatment sustained intense immune response at 4 days p.i. analyzed by qPCR. The results exhibited that the gene expression of TLR2 and TLR4 was significantly increased in the group coinjected with IP and leptospires than in the infected controls. And the expression of IL-1β and TNF-α were also up-regulated after IP treatment, except the expression of IL-1β in the kidney. Our results not only broaden the medicinal value of Iris, but also provide a competent candidate for the control of Leptospira infection.
钩端螺旋体病是由致病性钩端螺旋体引起的一种重要但被忽视的动物源性传染病。致病性钩端螺旋体有 300 多个血清型，而灭活菌只能提供短期的血清型特异性保护。钩端螺旋体病的治疗主要依赖于抗生素的使用。然而，抗生素的副作用和抗生素耐药性的风险仍然是主要问题。因此，人们期待能够减少对人体副作用且对钩端螺旋体病有效的替代药物。许多研究报道多糖可用作治疗感染和癌症的免疫刺激剂。在这项研究中，我们研究了从鸢尾中分离得到的多糖对钩端螺旋体病的保护作用。据我们所知，这是首次报道鸢尾多糖（IP）作为一种免疫刺激剂用于治疗感染。结果表明，IP 治疗可显著提高感染后用致死剂量钩端螺旋体攻击的仓鼠的存活率。此外，与未治疗的感染组相比，IP 治疗组在感染后 4 天（p.i.）时组织损伤和钩端螺旋体负荷减少。有趣的是，通过 qPCR 分析，IP 治疗在 4 天 p.i.时维持强烈的免疫反应。结果表明，与感染对照组相比，IP 与钩端螺旋体共注射组 TLR2 和 TLR4 的基因表达显著增加。此外，除肾脏中的 IL-1β 表达外，IP 治疗后 IL-1β 和 TNF-α 的表达也上调。我们的研究结果不仅拓宽了鸢尾的药用价值，而且为控制钩端螺旋体感染提供了一种有潜力的候选药物。
