Effects of earthworm extract on the lipid profile and fatty liver induced by a high-fat diet in guinea pigs

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD), characterized by the accumulation of excess fat in the liver in people who consume little or no alcohol, is becoming increasingly common around the world, especially in developed countries. Extracts from earthworms have been used as alternative therapies for a variety of diseases but not in NAFLD. Therefore, the aim of this study was to investigate the effect of earthworm extract (EE) on diet-induced fatty liver disease in guinea pigs. METHODS: EE was extracted, and the effect of EE on the lipid levels and liver damage in guinea pigs fed a high-fat diet (HFD) was assessed. Thirty male guinea pigs at 3 weeks of age were allocated equally to five groups, namely, chow diet, HFD, and HFD with different dosages (0.3, 1.4 and 6.8 µg per kg bodyweight per day) of EE for 4 weeks, and their body weight was monitored throughout the experiment. Liver tissues were examined for gross morphology and histology. Serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT) and aspartate aminotransferase (AST) were determined using an autoanalyser. RESULTS: HFD induced NAFLD in guinea pigs. HFD-fed guinea pigs that received EE treatment showed milder increases in the serum levels of TC, TG and LDL-C, as well as in the body weight growth rate, compared to the HFD group without EE supplementation. EE intervention reduced the number of lipid-containing hepatocytes, hepatocellular ballooning and sinusoidal distortion in the liver in HFD-fed animals. ALT in serum was significantly elevated by HFD. No statistically significant difference in ALT levels was found between the chow diet group and the HFD group with EE treatment. CONCLUSIONS: This study demonstrates that the administration of EE suppressed the induction of serum TC, TG and LDL-C in response to HFD. EE also reduced liver damage in HFD-fed guinea pigs. These findings suggest that EE has alleviating effects on dyslipidaemia and liver damage associated with NAFLD.