Suppression of hepatic dysfunction in tenascin-X-deficient mice fed a high-fat diet

Extracellular matrix glycoprotein tenascin-X (TNX) is the largest member of the tenascin family. In the present study, the contribution of TNX to liver dysfunction was investigated by administration of high-fat and high-cholesterol diet with high levels of phosphorus and calcium (HFCD) to wild-type (WT) and TNX-knockout (KO) mice. After 16 weeks of HFCD administration, the ratio of liver weight to body weight was approximately 22% higher in the HFCD-fed WT mice compared with the HFCD-fed TNX-KO mice, indicating hepatomegaly in HFCD-fed WT mice. Histological analyses with hematoxylin and eosin staining at 21 weeks revealed that hepatocyte hypertrophy in HFCD-fed TNX-KO mice was suppressed to 85% of that in HFCD-fed WT mice. By contrast, there was a 1.2-fold increase in lipid deposition in hepatocytes from HFCD-fed TNX-KO mice compared with HFCD-fed WT mice at 18 weeks, as demonstrated by Oil Red O staining. In addition, TNX-KO mice at 21 weeks and 27 weeks post-HFCD administration exhibited significant suppression of inflammatory cell infiltrate to 51 and 24% of that in WT mice, respectively. Immunofluorescence analysis for type I collagen and Elastica van Gieson staining demonstrated a clear hepatic fibrosis progression in HFCD-fed WT mice at 27 weeks, whereas hepatic fibrosis was undetected in HFCD-fed TNX-KO mice. The present findings indicated that TNX deficiency suppressed hepatic dysfunction induced by HFCD administration.