Chronic Intrathecal Infusion of Minocycline Prevents the Development of Spinal-Nerve Ligation-Induced Pain in Rats. Issue 3 (1st May 2007)

• Record Type: Journal Article
• Authors: Lin, Chia-Shiang; Tsaur, Meei-Ling; Chen, Chien-Chuan; Wang, Tao-Yeuan; Lin, Chih-Fu; Lai, Yuen-Liang; Hsu, Tien-Chi; Pan, Yu-Yen; Yang, Chen-Hsien; Cheng, Jen-Kun
• Is Part Of: Regional anesthesia and pain medicine. Volume 32:Issue 3(2007)
• Page Start: 209
• Page End: 216
• Publication Date: 2007-05-01
• Subjects: Intrathecal -- Minocycline -- Nerve ligation -- Neuropathic pain -- OX-42; Conduction anesthesia -- Periodicals; Pain medicine -- Periodicals; 617.964
• DOI: 10.1016/j.rapm.2007.01.005
• Languages: English
• ISSNs: 1098-7339

Abstract

Abstract : Background and Objectives: Minocycline is a second-generation tetracycline with multiple biological effects, including inhibition of microglial activation. Recently, microglial activation has been implicated in the development of nerve injury-induced neuropathic pain. In this study, the authors examined the effects of continuous intrathecal minocycline on the development of neuropathic pain and microglial activation induced by L5/6 spinal-nerve ligation in rats. Methods: Under isoflurane anesthesia, male Sprague-Dawley rats (200-250 g) received right L5/6 spinal-nerve ligation and intrathecal catheters connected to an infusion pump. Intrathecal saline or minocycline (2 and 6 μg/h) was given continuously after surgery for 7 days (n = 8 per group). The rat right hind paw withdrawal threshold to von Frey filament stimuli and withdrawal latency to radiant heat were determined before surgery and on days 1 to 7 after surgery. Spinal microglial activation was evaluated with OX-42 immunoreactivity on day 7 after surgery. Results: Spinal-nerve ligation induced mechanical allodynia and thermal hyperalgesia on the affected hind paw of saline-treated rats. Intrathecal minocycline (2 and 6 μg/h) prevented the development of mechanical allodynia and thermal hyperalgesia induced by nerve ligation. It also inhibited nerve ligation-induced microglial activation, as evidenced by decreased OX-42 staining. No obvious histopathologic change was noted after intrathecal minocycline (6 μg/h) infusion. Conclusions: In this study, the authors demonstrate the preventive effect of continuous intrathecal minocycline on the development of nociceptive behaviors induced by L5/6 spinal-nerve ligation in rats. Further studies are required to examine if continuous intrathecal minocycline could be used safely in the clinical setting.