Bilge CAN, Ayhan BOZKURT, Sibel BARIŞ, Hatice TÜRE, Özgü İŞGÜZAR, Sırrı BİLGE

Evaluation of antinociceptive and neurotoxic effects of intrathecal dexmedetomidine in rats

Amaç: İntratekal deksmedetomidin uygulaması ile analjezi elde edildiği gösterilmiştir. Bu çalışmada bir α2-reseptör agonisti olan deksmedetomidinin olası spinal nörotoksik etkilerinin değerlendirilmesi amaçlanmıştır. Materyal ve Metod: Ratlara intretekal kanülasyondan 3 gün sonra ya deksmedetomidin (3 μg/30 μL, i.t.) veya salin (30 μL, i.t.) uygulandı. İntratekal deksmedetomidinin veya salinin antinosiseptif, sedatif ve motor etkileri uygulamadan 90 dk sonra değerlendirildi. Termal nosiseptif eşiği değerlendirmek için kuyruk-çekme (tail-flick) ve sıcak-zemin (hot-plate) testleri kullanıldı. İlaç uygulamalarından yedi gün sonra, ratlar sakrifiye edildiler ve spinal kord spesmenleri ışık mikroskopisi ile histopatolojik değişiklikler açısından değerlendirildiler. Bulgular: İntratekal deksmedetomidin uygulaması antinosiseptif etkiye sahiptir. Tüm deksmedetomidin uygulanan ratlarda 40 dk süren adımlama (placing-stepping) refleksi kaybına sedasyon eşlik etmekteydi. Tüm ratlarda, mikroskopik inceleme sonucunda, beyaz madde posterior bölümünde hafif gliozis ve az sayıda iltihabi hücre infiltrasyonu gözlendi. Deksmedetomidin uygulanan dört ratta hafif (total skor 4-6) histopatolojik lezyonlar izlendi, ancak salin uygulanan ratlarla karşılaştırıldığında istatistiksel anlamlılık tespit edilmedi. Sonuç: İntratekal 3 μg/30 μL dozda deksmedetomidin uygulaması ile antinosiseptif etki elde ettik, ancak medulla spinaliste injuriye ait herhangi bir histopatolojik bulguya rastlamadık.

Ratlarda intratekal deksmedetomidin antinosiseptiv ve nörotoksik etkilerinin değerlendirilmesi

Objective: Dexmedetomidine has been reported to produce analgesia after intrathecal administration. In the present study the α2-adrenoceptor agonist dexmedetomidine was evaluated for its potential spinal neurotoxic effects. Material and Methods: Three days after intrathecal cannulation, rats were administered either dexmedetomidine (3 μg/30 μL, i.t.) or saline (30 μL, i.t.). Antinociceptive, sedative and motor effects of intrathecal administrations of dexmedetomidine or saline were evaluated during 90 min. The tail-flick and hot plate tests were used to assess the thermal nociceptive threshold. Seven days after drug administration, animals were sacrified and spinal cords were evaluated for histopathological changes by light microscopy. Results: Dexmedetomidine administered intrathecally produced antinociception. Antinociception was accompanied by immediate sedation and loss of placing-stepping reflexes that lasted over 40 min in all dexmedetomidine administered rats. In all rats, microscopic examination revealed mild gliosis and minimal infiltration of inflamatory r cells in posterior white matter. Mild (total score 4-6) histopathologic lesions were seen in four animals in dexmedetomidine adminisered rats, but there was no statistically significant difference when compared with the saline administered rats. Conclusion: We observed that intrathecal injections of dexmedetomidine at the dose of 3 μg/30 μL produce antinociception but did not cause any histopathological sign of injury in the spinal cord.

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