Sildenafil improves blood perfusion in steroid-induced avascular necrosis of femoral head in rabbits via a protein kinase G-dependent mechanism

Objective: The aim of the study were to evaluate the effect of sildenafil against avascular necrosis of femoral head (ANFH) in a rabbit model, and to study the role of protein kinase G (PKG) pathway and vascular endothelial growth factor (VEGF) in ANFH. Methods: Three weeks after inducing ANFH with methylprednisolone injection, 45 female adult New Zealand white rabbits were divided into three groups and treated as follows: group SI received daily intraperitoneal sildenafil with a dose of 10 mg/kg per day; group SD received daily sildenafil identically to group SI plus auricular vein injection DT3 (a specific PKG inhibitor); group NS received only normal saline. The blood perfusion function in the femoral head was measured by perfusion MRI and ink artery infusion. Bilateral femora heads were examined histopathologically for the presence of osteonecrosis; VEGF of tissue was examined by Western blot analysis; cGMP level and PKG activity were also measured. Results: The incidence of ANFH in SI group was significantly lower than that observed in NS and SD groups (p < 0.05). VEGF in SI group was increased compared to NS group. cGMP level and PKG activity were also significantly different between NS and SI group (p < 0.05). However, these effects of sildenafil in SD group were all markedly inhibited by the administration of DT3 compared to SI group. Conclusion: Sildenafil appear to increase the perfusion of femoral head by up-regulating VEGF through PKG pathway. The increased perfusion of femoral head could prevent ANFH.

___

1. Seguro LP, Rosario C, Shoenfeld Y. Long-term complications of past glucocorticoid use. Autoimmun Rev. 2013;12:629e632.

2. Shah KN, Racine J, Jones LC, Aaron RK. Pathophysiology and risk factors for osteonecrosis. Curr Rev Musculoskelet Med. 2015;8:201e209.

3. Boss J, Misselevich I. Osteonecrosis of the femoral head of laboratory animals: the lessons learned from a comparative study of osteonecrosis in man and experimental animals. Vet Pathol. 2003;40:345e354.

4. Al-Ameri H, Kloner R. Erectile dysfunction and heart failure: the role of phosphodiesterase type 5 inhibitors. Int J Impot Res. 2009;21:149e157.

5. Montani D, Chaumais M-C, Savale L, et al. Phosphodiesterase type 5 inhibitors in pulmonary arterial hypertension. Adv Ther. 2009;26:813e825.

6. Wang L, Chopp M, Szalad A, et al. Phosphodiesterase-5 is a therapeutic target for peripheral neuropathy in diabetic mice. Neuroscience. 2011;193:399e410.

7. Halcox JP, Nour KR, Zalos G, et al. The effect of sildenafil on human vascular function, platelet activation, and myocardial ischemia. J Am Coll Cardiol. 2002;40:1232e1240

8. Koneru S, Varma Penumathsa S, Thirunavukkarasu M, et al. Sildenafil-mediated neovascularization and protection against myocardial ischaemia reperfusion injury in rats: role of VEGF/angiopoietin-1. J Cell Mol Med. 2008;12:2651e2664.

9. Senthilkumar A, Smith RD, Khitha J, et al. Sildenafil promotes ischemia-induced angiogenesis through a PKG-dependent pathway. Arterioscler Thromb Vasc Biol. 2007;27:1947e1954.

10. Smith KM, Romanelli F. Recreational use and misuse of phosphodiesterase 5 inhibitors. J Am Pharm Assoc. 2005;45:63e72.

11. Li L, Jiang Q, Zhang L, et al. Angiogenesis and improved cerebral blood flow in the ischemic boundary area detected by MRI after administration of sildenafil to rats with embolic stroke. Brain Res. 2007;1132:185e192.

12. Persico M, Vincenti V, DiPalma T. Structure, expression and receptor-binding properties of placenta growth factor (PlGF). Curr Top Microbiol Immunol. 1999;237:31e40.

13. Yancopoulos GD, Davis S, Gale NW, Rudge JS, Wiegand SJ, Holash J. Vascularspecific growth factors and blood vessel formation. Nature. 2000;407:242e248.

14. Qin L, Zhang G, Sheng H, et al. Multiple bioimaging modalities in evaluation of an experimental osteonecrosis induced by a combination of lipopolysaccharide and methylprednisolone. Bone. 2006;39:863e871.

15. Sheng H, Zhang G, Wang YX, et al. Functional perfusion MRI predicts later occurrence of steroid-associated osteonecrosis: an experimental study in rabbits. J Orthop Res. 2009;27:742e747.

16. Zhang YF, Wang YXJ, Griffith JF, et al. Proximal femur bone marrow blood perfusion indices are reduced in hypertensive rats: a dynamic contrastenhanced MRI study. J Magn Reson Imaging. 2009;30:1139e1144.

17. Chen WT, Shih TTF, Chen RC, et al. Blood perfusion of vertebral lesions evaluated with gadolinium-enhanced dynamic MRI: in comparison with compression fracture and metastasis. J Magn Reson Imaging. 2002;15:308e314.

18. Fan L, Zhang C, Yu Z, Shi Z, Dang X, Wang K. Transplantation of hypoxia preconditioned bone marrow mesenchymal stem cells enhances angiogenesis and osteogenesis in rabbit femoral head osteonecrosis. Bone. 2015;81:544e553.

19. Fan L, Li J, Yu Z, Dang X, Wang K. Hypoxia-Inducible factor prolyl hydroxylase inhibitor prevents steroid-associated osteonecrosis of the femoral head in rabbits by promoting angiogenesis and inhibiting apoptosis. PLoS One. 2014;9: e107774.

20. Hang D, Wang Q, Guo C, Chen Z, Yan Z. Treatment of osteonecrosis of the femoral head with VEGF165 transgenic bone marrow mesenchymal stem cells in mongrel dogs. Cells Tissues Organs. 2012;195:495e506.

21. Yang C, Yang S-h, Du J-y, Li J, Xu W, Xiong Y. Vascular endothelial growth factor gene transfection to enhance the repair of avascular necrosis of the femoral head of rabbit. Chin Med J. 2003;116:1544e1548.

22. Mont MA, Jones LC, Einhorn TA, Hungerford DS, Reddi AH. Osteonecrosis of the femoral head: potential treatment with growth and differentiation factors. Clin Orthop Relat Res. 1998;355:S314eS335.

23. Ma X, Cui D, Zhao D. Vascular endothelial growth factor/bone morphogenetic protein-2 bone marrow combined modification of the mesenchymal stem cells to repair the avascular necrosis of the femoral head. Int J Clin Exp Med. 2015;8: 15528e15534.

24. Namba T, Koike H, Murakami K, et al. Angiogenesis induced by endothelial nitric oxide synthase gene through vascular endothelial growth factor expression in a rat hindlimb ischemia model. Circulation. 2003;108: 2250e2257.

25. Wang G, Zhang C, Sun Y, et al. Changes in femoral head blood supply and vascular endothelial growth factor in rabbits with steroid-induced osteonecrosis. J Int Med Res. 2010;38:1060e1069.

26. Sahara M, Sata M, Morita T, Nakajima T, Hirata Y, Nagai R. A phosphodiesterase-5 inhibitor vardenafil enhances angiogenesis through a protein kinase G-dependent hypoxia-inducible factor-1/vascular endothelial growth factor pathway. Arterioscler Thromb Vasc Biol. 2010;30:1315e1324.

27. Gao F, Sugita M, Nukui H. Phosphodiesterase 5 inhibitor, zaprinast, selectively increases cerebral blood flow in the ischemic penumbra in the rat brain. Neurol Res. 2005;27:638e643.

28. Fauzi A, Kamal A, Kurniawan A, Kodrat E. Role of sildenafil in acceleration of delayed union fracture healing on Sprague-Dawley rats model. Br J Med Med Res. 2015;8:419e428.

29. Histing T, Marciniak K, Scheuer C, et al. Sildenafil accelerates fracture healing in mice. J Orthop Res. 2011;29:867e873.

30. Ebrahimi F, Shafaroodi H, Asadi S, et al. Sildenafil decreased cardiac cell apoptosis in diabetic mice: reduction of oxidative stress as a possible mechanism. Can J Physiol Pharmacol. 2009;87:556e564.