Morphometry analysis
Liver and skeletal muscle tissues were fixed in 10% formaldehyde, embedded in paraffin, and cut into 5 μm serial sections for staining with H&E and Oil Red O. Histopathological changes were observed using a fluorescence microscope system (TE2000, Nikon Japan) and representative images were presented.
Transcriptomic analysis
Total RNA was extracted from liver tissue using TRIZOL reagent and purified using the NanoPhotometer® spectrophotometer (IMPLEN, CA, USA) to eliminate ribosomal RNA, and then stored at -80°C prior for further analysis by NEBNext® UltraTM RNA Library Prep Kit for Illumina® (NEB, USA) following manufacturer’s recommendations. Sample sets were constructed with six individual samples from C57, KK-Ay and KK-Ay+Dios group (three samples per group). RNA-sequence analysis was conducted by RNA-sequence analysis conducted by Beijing Novogene Genomics Technology Co. Ltd. (Beijing, China). The Gene Ontology (GO) enrichment analysis of differentially expressed genes was implemented by the clusterProfiler R package, in which gene length bias was corrected. GO terms with corrected P value less than 0.05 were considered significantly enriched by differential expressed genes. ClusterProfiler R package was used to test the statistical enrichment of differential expression genes in KEGG pathways.