Article
Steroids enhance femoral head lateral epiphysial artery contraction
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Published: | June 13, 2005 |
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Outline
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Introduction
The pathomechanism of steroid induced femoral head necrosis is thought to be disturbed femoral head blood flow. The lateral epiphysial arteries represent the main blood supply to the femoral head, but the effect of steroid treatment on their vasotonus has not yet been investigated. The purpose of this study was to investigate the influence of steroid treatment on femoral head lateral epiphysial artery wall tension.
Material and Methods
From 18 female domestic pigs, 9 were randomly allocated to receive 24hour methylprednisolone treatment while their 9 sister pigs received the placebo control in a blinded fashion. After sacrification of the animal, the femoral heads were removed, cut into frontal slices, the lateral epiphysial artery segments were isolated under the microscope, and mounted as ring preparations on a small vessel myograph. Isometric active tension was measured in relation to cumulating doses of the vasoconstrictors noradrenaline and endothelin-1, and the vasodilator bradykinin.
Results
Vasodilation under bradykinin was significantly lower in the vessels of the steroid treated animals. Vasocontraction to endothelin-1 was significantly stronger in the vessels from the steroid treated animals. Noradrenaline exerted a dose-dependent vasocontraction without significant difference between both experimental groups.
Discussion
These data indicate that methylprednisolone enhances the contraction of femoral head lateral epiphysial arteries. As contraction leads to lower blood flow in the vessel involved, femoral head blood flow may be impaired by this mechanism. This may be a previously not described pathomechanic factor in femoral head necrosis.