Serial percutaneous liver biopsies in laboratory rats

The percutaneous liver biopsy is an essential tool that provides histological assessment of the liver for diagnostic, therapeutic, and prognostic purposes. To date, this procedure has not been described in the laboratory setting for studies with small laboratory animals. The aim of the present study was to assess the feasibility and diagnostic value of performing serial percutaneous liver biopsies in a rat model of chronic liver disease. Adult male Sprague-Dawley rats (N = 27) were exposed to thioacetamide (TAA) for six months, throughout which serial liver biopsies were performed at baseline and two, four, and six months. An additional group of isocaloric-fed rats (N = 6) not exposed to TAA served as controls. Following the biopsies at each time point, a subset of rats was killed to determine whether the histologic findings seen in the biopsies were consistent with the histology of the entire organ. Seven rats (21%) died from complications of the procedure (one from anaesthetic overdose and six from postbiopsy bleeding). A total of 72 biopsies were performed, resulting in a procedural mortality of 8%. In the remaining rats, biopsies were well tolerated with no overt signs of pain or discomfort. Histologic activity and fibrosis in the biopsy specimens reflected the results observed in wedge sections of liver tissue at all stages of TAA-induced liver disease. The results of this study indicate that serial percutaneous liver biopsies can be successfully performed and reflect the extent of hepatic injury in a common model of chronic liver disease.