慢性馬尾圧迫下の神経根内血流障害に対する血流改善効果―選択的EP4受容体アゴニストとプロスタグランジンE1誘導体投与後の血流量の比較検討

Effect for Improvement of Blood Flow in Chronically Compressed Nerve Roots. Comparison of Effect between Selective EP4-receptor Agonist and Prostaglandin E1 Derivative

　抄録：慢性馬尾圧迫下において，EP4受容体アゴニストの神経根内血管に対する血管拡張と血流量改善作用を，プロスタグランジンE1誘導体と比較した．雑種成犬25頭を用いて慢性馬尾圧迫モデルを作製した．実験系はOP-1206α-CD（プロスタグランジンE1誘導体）3ng/kg/min投与群（n＝5）〔以後OP（3）投与群〕，10ng/kg/min投与群（n＝5）〔以後OP（10）投与群〕，ONO-4819・CD（EP4受容体アゴニスト）3ng/kg/min投与群（n＝5）〔以後EP4（3）投与群〕，10ng/kg/min投与群（n＝5）〔以後EP4（10）投与群〕と，対照群として生理食塩水投与群（n＝5）（以後コントロール群）の5群を設定した．薬剤投与後10分ごとに神経根内血管の血管径と血流量の計測を行った．OP（3），OP（10），EP（10）投与群では血管が拡張し，血流量が増加した．特に，EP（10）投与群では他の4群に比較して有意に血流量が増加した．これに対して，EP（3）投与群では血管が収縮し，血流量が減少した．以上の結果から，高濃度のEP4受容体アゴニストは，腰部脊柱管狭窄による神経根内血流を改善させる可能性があるといえる．

　We evaluated the vasodilative effect and improvement of blood flow in nerve roots by comparing selective EP4 receptor agonist (EP4) with prostaglandin E1 derivative (PGE1) under chronic cauda equina compression in dogs. A total of twenty-five dogs were used as the chronic cauda equina compression model. OP (3) group was administrated 3ng/kg/min OP-1206α-CD (PGE1), OP (10) group was administrated 10ng/kg/min OP-1206α-CD (PGE1), and EP (3) group was administrated 3ng/kg/min ONO-4819・CD (EP4) and EP (10) group was administrated 10ng/kg/min ONO-4819・CD (EP4). Control group was administrated normal saline as a control. Diameter of blood vessels and blood flow were observed every ten minutes after injection. In the OP (3), OP (10) and EP (10) groups, the blood vessels dilated and blood flow increased after injection. In EP (10) group, the blood flow increased significantly compared with the other four groups. In contrast, the blood vessels contracted and the blood flow diminished after injection of EP (3). These results suggested that a high concentration of EP4 might have the effect of improving blood flow in nerve roots under lumbar spinal stenosis.