Effect of spinal cord stimulation on expression of neuronal nitric oxide synthase in rats with diabetic neuropathic pain / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of spinal cord stimulation on the expression of neuronal nitric oxide synthase (nNOS) in the rats with diabetic neuropathic pain.Methods Forty-eight pathogen-free healthy male Sprague-Dawley rats,aged 2 nonths,weighing 250-300 g,were divided into 4 groups (n =12 each) using a random number tablecontrol group (group C),diabetes mellitus group (group DM),sham operation group (group S) and spinal cord stimulation group (group SCS).Diabetic neuropathic pain was produced by intraperitoneal injection of 1％ streptozocin 75 mg/kg and confirmed by blood glucose level＞16.7 mmol/L on day 2 after streptozocin injection.Electrodes were implanted into the epidural space at 19 days after successful establishment of the model in S and SCS groups,and in addition spinal cord stimulation (frequency 50 Hz,pulse width 0.2 ms,intensity=2/3 of the lowest intensity) was performed for 30 min once a day at 26-28 days after successful establishment of the model in group SCS.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before establishment of the model (T1) and 2,7,14 and 28 days after successful establishment of the model (T2-5).The rats were sacrificed after the last measurenent of MWT at T5,and the lumbar segment of the spinal cord was removed for determination of nitric oxide (NO) content and nNOS expression in spinal cord tissues.Results Compared with group C,the MWT was significantly decreased at T4.5,and the NO content and nNOS expression in the spinal cord were increased in DM,S and SCS groups (P＜0.05).Compared with group DM,the MWT was significantly increased at Ts,and the NO content and nNOS expression in the spinal cord were decreased in group SCS (P＜0.05).Conclusion The mechanism by which spinal cord stimulation allenuales diabetie neuropalhic pain is related to inhibiting nNOS expression and reducing NO production in rals.