The Expression Of Hypoxia-inducible Factor-1α And Gulcose Transporter-1 In The Annulus Fibrosus Of Different Ages Rats

IntroductionThe intervertebral disc(IVD) is the largest vascular cartilaginous structure tissue.The IVD is composed of nucleus pulposus(NP) and annulus fibrosus(AF) which reside in an hypoxic environment.As we know,during aging,many changes involving the proportions and biochemical properties of the matrix occur in the degeneration of intervertebral disc.HIF-1 protein consists of two subunits,HIF-1αand HIF-1βand it is a molecule that detects the oxygen tension.Under normoxic conditions HIF-1αprotein undergoes rapid degradation by a proteasome.Hypoxia increases HIF-1αprotein stability by inhibiting its degradation.It is a master regulator of oxygen homeostasis in cell and tissue,and plays a critical roles in physiological and pathological process. There are many research on the regulation of HIF-1αin hypoxia.It has been shown that HIF-1αis a regulatory factor of vascular endothelial growth factor(VEGF),which is the key protein for the neovascularization process.The expression of HIF-1αin human articular cartilage has been reported.Recent studies on the presence of HIF-1αwithin rat intervertebral discshas been proven.Surprisingly,it was found that the rats (8-10week) are possible not old enough as to degenerate.HIF-1αhas also been found in the NP of normal human IVD.On the recently research suggest that glucose transport and HIF-1αparticipate in hypoxia regulated processes in the avascular regions of the human IVD and that degeneration affects the expression of glucose transporters.The expression of HIF-1αin rat IVD(especially in AF) is not well understood,and there is no research on the expression of HIF-1αwith the change of age.The goal of the present study is to examine the expression of HIF-la and GLUT-1 in the intervertebral disc of Wistar rats of different ages.Materials and MethodsFifty Wistar rats were divided into 5 groups according to their different months:1,3,6,12,18-month groups.The expression of HIF-1αand GLUT-1 in annulus fibrosus of intervertebral disc was observed by immunohistochemistry and westernblot.ResultsThe expression of HIF-1αand GLUT-1 in the anulus fibrosus of intervertebral disc varied with aging.From low-month-old group(1-3 month old) to adult group(6-12 month old) HIF-1αand GLUT-1 expression gradually reduced,while there is a significant increase in the older group(18 month old)ConclusionsThe HIF-1αinduces high GLUT-1's expression and delay the intervertebral disc degeneration.It is possible that is the treatment of intervertebral dics degeneration as a research method.