Hyperbaric oxygen preconditioning promotes angiogenesis in rat liver after partial hepatectomy

• Published in: Life sciences (1973) 2008-08, Vol.83 (7), p.236-241
• Main Authors: Ren, Ping, Kang, ZhiMing, Gu, GuoJun, Liu, Yun, Xu, WeiGang, Tao, HengYi, Zhang, John H., Sun, XueJun, Ji, Hui
• Format: Article
• Language: English
• Subjects: Angiogenesis; Animals; Cell Proliferation - drug effects; Endothelial Cells - metabolism; Gene Expression Regulation - drug effects; Hepatectomy; Hepatocytes - metabolism; Hyperbaric oxygen preconditioning; Hyperbaric Oxygenation; Hypoxia inducible factor-1; Hypoxia-Inducible Factor 1, alpha Subunit - biosynthesis; Immunohistochemistry - methods; Liver Regeneration - drug effects; Male; Neovascularization, Physiologic - drug effects; Oxygen - pharmacology; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - biosynthesis
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2008.06.011

Hyperbaric oxygen preconditioning (HBO-PC) increases the level of HIF-1α (hypoxia inducible factor-1α) and its target gene VEGF (vascular endothelial growth factor) which is involved in angiogenesis. Liver regeneration is an angiogenesis-dependent process. We hypothesized that HIF-1α and VEGF mediated the angiogenesis effect of HBO-PC on regenerating rat liver. Male Sprague Dawley rats received HBO-PC followed by 70% partial hepatectomy. Proliferation of hepatocytes and endothelial cells was evaluated by BrdU (bromodeoxyuridine) staining. Microvascular density was assessed by immunohistochemistry. mRNA expression of HIF-1α was assessed by quantitative RT-PCR and protein levels of HIF-1α and VEGF were assessed by western blot. HIF-1α DNA-binding activity was determined with an ELISA-based kit. HBO-PC increased the proliferation index of endothelial cells and microvascular density at 48 h after partial hepatectomy. The protein level and DNA-binding activity of HIF-1α and the protein level of VEGF were increased by HBO-PC before and after partial hepatectomy. Partial hepatectomy alone also increased proliferation index and the expressions of HIF-1α and VEGF. Our results indicated that the angiogenesis effect of HBO-PC on liver after partial hepatectomy could be achieved by increased HIF-1α activity and VEGF expression. However, the angiogenic effect of HBO-PC is moderate and HBO-PC failed to produce additional effect on the enhancement of HIF-1α and VEGF induced by partial hepatectomy alone.