Expression of Nestin in Remodelling of α-Naphthylisothiocyanate-induced Acute Bile Duct Injury in Rats

Abstract

The function of the intermediate filament protein nestin is poorly understood. The significance of nestin expression was assessed in α-naphthylisothiocyanate (ANIT)-induced cholangiocyte injury lesions in F344 rats. Liver samples obtained from rats injected intraperitoneally with ANIT (75 mg/kg) on post-injection days 0 (control) and 1-12 were labelled immunohistochemically for expression of nestin and markers specific for mesenchymal cells (vimentin), hepatic stellate cells (HSCs) (desmin and glial fibrillary acidic protein [GFAP]), endothelial cells (rat endothelial cell antigen [RECA]-1), cholangiocytes (cytokeratin [CK] 19) and cellular proliferation (Ki67). Cholangiocyte injury led to infiltration of neutrophils and macrophages followed by aggregation of mesenchymal cells and regeneration of bile ducts. Nestin expression was detected in mesenchymal cells (vimentin positive) on days 1-7 with a peak on days 3-5 and in newly-formed RECA-1-positive endothelial cells on day 3. Nestin expression was also observed in regenerating CK19-positive cholangiocytes on days 2-5, with a peak on day 3. Labelling for Ki67 showed proliferation of cholangiocytes, mesenchymal cells and HSCs. Real-time reverse transcriptase polymerase chain reaction with microdissected samples showed significantly elevated nestin mRNA on day 3. The findings suggest an association between nestin expression and cellular proliferation. Based on these findings, it was considered that nestin-expressing mesenchymal cells, HSCs and endothelial cells may be possible progenitors of repopulating cholangiocytes. Nestin expression may serve as an indicator for cellular remodelling and behaviour of injured and repopulating bile ducts.