Fariba Mirzaei Bavil
1, Mohammad Reza Alipour
1, Rana Keyhanmanesh
1, Alireza Alihemmati
2, Rafigheh Ghiyasi
2, Gisou Mohaddes
2*1 Tuberculosis and Lung Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
2 Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Abstract
Purpose: Hypoxia is a condition
of decreased availability of oxygen. When cells are exposed to a low oxygen
environment, they impel the hypoxia responses to adapt to new situation. The
hypoxia response leads to the activation of various cellular signaling pathways.
The aim of this study was to evaluate the effect of ghrelin on angiogenesis,
Hypoxia-Inducible-Factor-1α (HIF-1) and Vascular endothelial growth factor
(VEGF) levels in normobaric hypoxia situation.
Methods: Twenty four animals
were divided into 4 groups (n=6): control (C), ghrelin (Gh), hypoxia (H), and
hypoxic animals that received ghrelin (H+Gh). Hypoxia (11%) was induced by an
Environmental Chamber System GO2 Altitude. Animals in ghrelin groups received a
subcutaneous injection of ghrelin (150 μg/kg/day) for 14 days.
Results: Our results showed that
hypoxia significantly (p<0.05) increased angiogenesis without any
significant changes on HIF-1 and VEGF levels, whereas ghrelin significantly
(p<0.05) decreased angiogenesis, expression of HIF-1 and VEGF in this
condition. Ghrelin administration did not show any significant changes in
normal conditions.
Conclusion: Ghrelin had no effect
on angiogenesis, expression of HIF-1 and VEGF in normal oxygen conditions but
it reduced angiogenesis process in lung tissue with reducing the level of HIF
and VEGF in hypoxic condition. Therefore, effect of ghrelin on angiogenesis
could be related to blood oxygen level.