Protective effect of extracts on adult zebrafish
To further confirm the protective effect of extracts, we treated 1-month-old zebrafish (designed as ”0 week”) with a 1.75% glucose and 10% cholesterol diet for 4 weeks to establish a type 2 diabetic zebrafish model. The sample treatment group was given the indicated concentrations of extracts from 5th week to 8th week. The control group was fed a normal commercial diet. Zebrafish in each group were fed twice a day, and the medium was replaced with a fresh one group. After fasting for 12 h on the last day of the 8th week, the body weight of the zebrafish was measured. The muscular endurance of ginseng-treated zebrafish was evaluated following a previous method (Kim et al., 2019).
The zebrafish were euthanized by MS 222, and muscle tissue was collected for analysis. The levels of FBG, INS, TG, T-CHO, FFA, MG, SOD, GSH-PX, CAT, MDA, TNF-ɑ and IL-6 were calculated following kit instructions.
In addition, the heart and muscle tissues of zebrafish in each group were collected and treated with 4% paraformaldehyde for 48 h. The hematoxylin-eosin (HE), TUNEL assay and DAPI staining, and immunohistochemistry (IHC) staining were performed by previous protocols (Li et al., 2018).