In vivo and in vitro efficacy of crocin against Echinococcus multilocularis

Chuanchuan Liu,Ri-Li Ge,Haining Fan,Lan Ma,Lu Guan

doi:10.1186/s13071-021-04866-4

Abstract

BackgroundAlveolar echinococcosis (AE) is a fatal zoonosis caused by the larvae of Echinococcus multilocularis. However, current chemotherapy treatment options are based on benzimidazoles [albendazole (ABZ) and mebendazole], which have limited efficacy. Therefore, novel drugs are necessary for the treatment of this disease.MethodsThe anthelmintic effects of crocin were tested on E. multilocularis metacestodes, germinal cells and protoscoleces in vitro. Human foreskin fibroblasts (HFFs) and Reuber rat hepatoma (RH) cells were used to assess cytotoxicity. The in vivo efficacy of crocin was investigated in mice following secondary infection with E. multilocularis. Furthermore, collagen deposition and degradation in host tissues around the metacestodes were evaluated.ResultsIn vitro, crocin had a median effective concentration of 11.36 μM against cultured E. multilocularis metacestodes, while it reduced germinal cell viability at a median inhibitory concentration of 10.05 μM. Crocin was less toxic to HFFs and RH mammalian cell lines than to metacestodes. Transmission electron microscopy revealed that crocin treatment resulted in structural damage in the germinal layer. In addition, 60.33 ± 3.06% of protoscoleces were killed by treatment with 10 μM crocin for 7 days, indicating that crocin has a parasiticidal effect. In vivo, the metacestode weight was significantly reduced after the administration of crocin at 50 mg/kg and 100 mg/kg (55.1 and 68.1%, respectively). Metacestode pathology showed structural disruption of the germinal and laminated layers after crocin treatment. The crocin- and ABZ-treated groups presented significant increases in the levels of interleukin (IL)-2 and IL-4. Furthermore, crocin inhibited the expression of matrix metalloproteinases (MMPs) (MMP2 and MMP9) and promoted collagen deposition in the metacestode.ConclusionsCrocin was demonstrated to exert parasiticidal activity against E. multilocularis in vitro and in vivo, and can be developed as a novel drug for the treatment of AE.Graphical abstract

Highlights

Alveolar echinococcosis (AE) is a fatal zoonosis caused by the larvae of Echinococcus multilocularis
In vitro activity of crocin against E. multilocularis metacestodes In the RT-PCR analysis, mouse Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was not amplified from metacestode vesicles or germinal cells, confirming the absence of host cells, while the E. multilocularis GAPDH-specific gene was amplified from metacestode vesicles and germinal cells (Fig. 1a)
The results showed that the messenger RNA (mRNA) expression of type I and type III collagen was higher in crocin-treated metacestodes than in control metacestodes (Fig. 9e)

Summary

Introduction

Alveolar echinococcosis (AE) is a fatal zoonosis caused by the larvae of Echinococcus multilocularis. Current chemotherapy treatment options are based on benzimidazoles [albendazole (ABZ) and mebenda‐ zole], which have limited efficacy. Novel drugs are necessary for the treatment of this disease. Alveolar echinococcosis (AE) is a rare zoonotic parasitic disease in humans caused by the larvae of Echinococcus multilocularis. Liu et al Parasites Vectors (2021) 14:364 portal venous system and reach the liver, where they usually settle and develop as larvae (metacestodes) [5]. Once patients are diagnosed with AE, the disease is usually at an advanced stage and the patients have obvious symptoms and signs, including abdominal pain, jaundice, weight loss and even liver failure [6]. All patients should receive chemotherapy with benzimidazoles, mainly albendazole (ABZ) and mebendazole (MBZ).

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