Z Gastroenterol 2012; 50 - P3_40
DOI: 10.1055/s-0031-1295882

The significance of appropriate controls in surgical microRNA studies of the liver

W Werner 1, NJ Raschzok 1, H Sallmon 2, A Leder 1, S Lippert 1, H Morgül 3, S Jonas 4, P Neuhaus 1, IM Sauer 1
  • 1Charite, Department of General, Visceral and Transplantation Surgery, Berlin
  • 2Department of Neonatology, Charité – Campus Virchow, Universitätsmedizin Berlin, Berlin
  • 3Department of Visceral, Transplantation, Thoracic, and Vascular Surgery, Universitätsklinikum Leipzig, Leipzig
  • 4Department of General Visceral and Transplantation Surgery, University Hospital, Leipzig

Introduction: MicroRNAs (miRNAs) are a novel class of small, non-coding nucleotides that have been shown to critically affect hepatocyte proliferation during liver development, regeneration, and carcinogenesis. Studies on liver regeneration following partial hepatectomy (PH) have identified several miRNAs that could be involved in the regulation of liver regeneration. In this regard, the impact of the surgical procedure itself on miRNA expression patterns of the liver should not be missed.

Methods: We addressed the question weather surgery influences miRNA expression of the liver by performing sham laparotomy or 70% PH in Wistar rats (n=3). Liver tissue was harvested after 12, 24, and 48 hours after surgery. As control, liver from non-treated animals was used. Total RNA was isolated, analysed using microarrays, and validated via qRT-PCR.

Results: We found 45 out of 323 detected miRNAs (13.93%) to be significantly differentially expressed after sham laparotomy. Out of these, eleven miRNAs were differentially expressed after PH but also deregulated after sham laparotomy, including miR–105, miR–133a/b, miR–466c, and miR–483. 31 miRNAs showed significant regulation after sham laparotomy but not after PH while miR–194, mir–23b, and miR–29a showed significant upregulation after sham operation but were downregulated after PH. Interestingly, some of these miRNAs have already been published as being involved in the regulation of liver regeneration.

Conclusion: Surprisingly, miRNA expression patterns of the liver change significantly after sham laparotomy. This may be due to anaesthesia, inflammation, and wound healing. Apart from the reasons of these changes, it is very important to notice that even relatively small interventions have significant impact on the miRNA expression of the liver. This fact should especially receive attention while interpreting experimental and clinical data without appropriate control groups.

liver regeneration - microRNA - sham laparotomy