RhoA/Rho-kinase contributes to chronic pain following thoracotomy by up-regulating glutaminase 1 expression in rat spinal dorsal cord / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate whether RhoA/Rho-kinase contributes to the occurrence of chronic post-thoracotomy pain (CPSP) by up regulation of glutaminase 1 (GLS1) expression in the spinal dorsal cord.</p><p><b>METHODS</b>Twenty five male Sprague Dawley (SD) rats were divided into control group (n=5) and model group (n=20). The rats in the model group were randomized into two sub groups (n=10) for observation on day 10 and day 21 after thoracotomy, and each group was further divided into CPSP and non CPSP groups according to the behavioral test results. All the rats were sacrificed after behavioral test for examination of GLS1 and RhoA expressions in the spinal cord using Western blotting and RT PCR. We also compared the effect of the Rho kinase inhibitor fasudil and saline, both injected intraperitoneally daily at 10 mg/kg for 7 consecutive days following thoracotomy, on CPSP and GLS1 expression in 30 male SD rats on day 21 after thoracotomy.</p><p><b>RESULTS</b>Compared with the control group, the rats with CPSP showed significantly increased expressions of GLS1 and RhoA mRNA in the spinal cord on both day 10 and day 21 following thoracotomy (P<0.01), but the rats without CPSP did not show obvious changes in GLS1 and RhoA expressions. In fasudil treated rats, the mechanical pain threshold was obviously increased and the expressions of GLS1 and RhoA were significantly reduced as compared with those in saline treated rats (P<0.01).</p><p><b>CONCLUSION</b>RhoA plays an important role in the occurence of CPSP by up-regulating the expression of GLS1 in the spinal dorsal cord of rats.</p>

Effects of dexmedetomidine on propofol dosage in target-controlled infusion and hemodynamics during laparoscopic surgery under general anesthesia / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the effects of dexmedetomidine (Dex) on propofol dosage in target-controlled infusion (TCI) and hemodynamics in patients undergoing laparoscopic surgery under general anesthesia.</p><p><b>METHODS</b>Sixty patients undergoing laparoscopic surgery under general anesthesia were randomly divided into control group (n=30) and the Dex group (n=30). The patients in Dex group received a loading dose of Dex (1 µg/kg, infused within 10 min) before the surgery followed by continuous infusion at the rate of 0.3 µg·kg(-1)·h(-1) till the end of the surgery, and the control patients received saline infusion in the same manner. Heart rate, blood pressure, bispectral index (BIS), and propofol dose in TCI were recorded during induction and maintenance of anesthesia. The incidence of hypotension and bradycardia were observed during and after the surgery.</p><p><b>RESULTS</b>No difference was found in the incidence of hypotension and bradycardia between the control group and Dex group (P>0.05), but heart rate and blood pressure were lower in Dex group during extubation (P<0.05). The dose of propofol in TCI was significantly less in Dex group than in the control group (P<0.05).</p><p><b>CONCLUSION</b>Dex can reduce hemodynamic abnormalities caused by extubation and decrease the dosage of propofol in TCI, and may serve as an ideal adjuvant drug for general anesthesia.</p>

Expressions of neuropathic pain-related proteins in the spinal cord dorsal horn in rats with bilateral chronic constriction injury / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the pain-related behavioral changes in rats with bilateral chronic constriction injury(bCCI)and identify the expressions of neuropathic pain-related proteins.</p><p><b>METHODS</b>The bCCI models were established by ligating the sciatic nerves in female Sprague Dawley rats. Both mechanical hyperalgesia and cold hyperalgesia were evaluated through electronic von Frey and acetone method. Liquid chromatography-mass spectrometry/mass spectrometry was applied to characterize the differentially expressed proteins.</p><p><b>RESULTS</b>Both mechanical withdrawal threshold and cold hyperalgesia threshold decreased significantly on the postoperative day 7 and 14, when compared with na ve or sham rats(P <0.05). Twenty five differentially expressed proteins associated with bilateral CCI were discovered, with eighteen of them were upregulated and seven of them downregulated.</p><p><b>CONCLUSIONS</b>The bCCT rats have remarkably decreased mechanical and cold hyperalgesia thresholds. Twenty five neuropathic pain-related proteins are found in the spinal cord dorsal horn.</p>

Prevalence and risk factors of chronic post-thoracotomy pain in Chinese patients from Peking Union Medical College Hospital / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In clinical practice, the mechanisms underlying chronic post-surgical pain (CPSP) remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after thoracic surgery and to identify possible risk factors associated with the development of chronic post-thoracotomy pain in Chinese patients. The secondary goal was to determine whether the difference between pre- and post-operative white blood cell (WBC) counts could predict the prevalence of CPSP after thoracotomy. The impact of chronic pain on daily life was also investigated.</p><p><b>METHODS</b>We contacted by phone 607 patients who had undergone thoracotomy at our hospital during the period February 2009 to May 2010. Statistical comparisons were made between patients with or without CPSP.</p><p><b></b>RESULTS</p><p><b>RESULTS</b>were ultimately analyzed from 466 qualified patients. The overall incidence of CPSP was 64.5%. Difference between pre- and post-operative WBC counts differed significantly between patients with or without CPSP (P < 0.001) and was considered as an independent risk factor for the development of CPSP following thoracotomy (P < 0.001). Other predictive factors for chronic pain included younger age (< 60 years, P < 0.001), diabetes mellitus (P = 0.023), acute post-operative pain (P = 0.005) and the duration of chest tube drainage (P < 0.001). At the time of interviews, the pain resulted in at least moderate restriction of daily activities in 15% of the patients, of which only 16 patients had paid a visit to the doctor and only three of them were satisfied with the therapeutic effects.</p><p><b>CONCLUSIONS</b>Chronic pain is common after thoracotomy. WBC count may be a new independent risk factoring surgical patients during peri-operative period. Besides, age, diabetes mellitus, acute post-operative pain, and duration of chest tube drainage may also play a role in chronic post-surgical pain occurrence.</p>