کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2848522 | 1571354 | 2006 | 8 صفحه PDF | دانلود رایگان |

Methods to study exercise are evolving from classically integrative organ approaches towards the more fundamental cellular reactions. While in vitro cellular and molecular methods are well established, only recently has in vivo molecular manipulation been widely used. This review discusses two complementary methods for determining in vivo the significance of one gene thought important to exercise: vascular endothelial growth factor (VEGF). Because VEGF deletion is embryonically lethal, its study requires conditional and/or organ-targeted strategies. We inactivated the muscle VEGF gene in two ways:(A)targeting a tissue volume of a few hundred cells in one muscle in VEGFloxP mice by local delivery of cre recombinase. LoxP sites, small fragments of DNA flanking a region of VEGF exon 3, are recognized by cre recombinase, which results in recombination and inactivation of the VEGF gene expression. The effects on VEGF and muscle capillarity were subsequently studied immunohistochemical analysis.(B)VEGF was deleted lifelong, but only in muscle, by crossbreeding VEGFloxP mice with mice expressing Cre driven by the muscle creatine kinase (MCK) promoter. Effects on exercise capacity and development of compensatory pathways were studied. Both approaches reduced muscle capillarity 65%, showing no alternative angiogenic pathways to restore vascularity. Treadmill endurance time was only ∼20% of normal, demonstrating functional significance of VEGF. Muscle structural and functional responses to exercise training were not apparent. Thus, single gene molecular manipulation can be performed in intact mice and a range of physiological processes studied.
Journal: Respiratory Physiology & Neurobiology - Volume 151, Issues 2–3, 28 April 2006, Pages 159–166