Workflow diagram of the feeding and tissue processing of zebrafish.

A representative frozen section (× 200, hematoxylin and eosin) (a) of a liver was obtained from zebrafish No. 5 (low fatty liver group) and stained with oil red O. In the same area of Fig. 1a, a 10% fatty change was observed with oil red O positive stain (box) (× 200) (b). Higher magnification of the oil red O positive area (lower box marked with solid line in Fig. 1b) (× 400) (c). A representative section of oil red O stain from the zebrafish before feeding a high cholesterol diet (× 200) (d) (see the workflow diagram of Fig. 1). The high fatty liver group contains zebrafish that have a proportion score of no less than 50 (× 200) (e). At higher magnification (yellow box in Fig. 1e), both macrovesicular and microvesicular fatty changes were detected at high levels in the high fatty liver group compared to the negative internal control of the glandular epithelial cells in the stomach (left upper side) (× 400) (f).

A total of 1772 genes were upregulated and 3293 genes were downregulated with statistical significance (a,b). In the Venn diagram, upregulated or downregulated lncRNAs with more than tenfold changes are featured (b). The smear plot (c) and volcano plot (d) between the high and low fatty change groups are shown. Eight conserved lncRNAs are placed and featured in each plot (c,d).

The human tissue expression profiles represented by FPKM/TPM (a) and exosome expression profiles represented by FPKM (b) were evaluated on 8 conserved lncRNAs. invasive NFPAs, invasive nonfunctional pituitary adenomas exosomes; non-invasive NFPAs, non-invasive nonfunctional pituitary adenoma exosomes; tuberculosis, active tuberculosis patient serum exosomes; A431, squamous cell carcinoma cell line exosomes; BJ, foreskin fibroblast cell line exosomes; HepG2, hepatocellular carcinoma cell lines; MCF7, human breast cancer cell line exosomes; MDA-MB-23a, human breast cancer cell line exosomes; normal people blood, normal people blood exosomes (http://www.noncode.org/).

lncRNA–mRNA (protein-coding gene) interaction network for 5 out of 8 conserved lncRNAs in zebrafish. Among the eight candidates, five (ZFLNCG11695, ZFLNCG07435, ZFLNCG06796, ZFLNCG10246, and ZFLNCG03169) of which were identified as having related protein-coding genes of zebrafish, and three (ZFLNCG07435, ZFLNCG10246, and ZFLNCG03169) of which were identified as having genes (prkcha, ankha, si:dkey-226m8.9, kcnjla.2, trpv6, kcnjla.1, and znf148) related to human disorder. Information provided by ZFLNC (http://www.zflnc.org/) and zfin (https://zfin.org/).

Frozen sections of each zebrafish with longitudinal sections were used for fat staining. (a) When the liver (circled) began to appear on the cut surface (b) of the frozen section, it was cut into serial sections with a thickness of 4 µm (c).