Mechanism of persistent hyperalgesia in neuropathic pain caused by chronic constriction injury

Transmembrane member 16 A(TMEM16 A) is involved in many physiological functions, such as epithelial secretion, sensory conduction, nociception, control of neuronal excitability, and regulation of smooth muscle contraction, and may be important in peripheral pain transmission. To explore the role of TMEM16 A in the persistent hyperalgesia that results from chronic constriction injury-induced neuropathic pain, a rat model of the condition was established by ligating the left sciatic nerve. A TMEM16 A selective antagonist(10 μg T16 Ainh-A01) was intrathecally injected at L5–6. For measurement of thermal hyperalgesia, the drug was administered once at 14 days and thermal withdrawal latency was recorded with an analgesia meter. For measurement of other indexes, the drug was administered at 12 days,once every 6 hours, totally five times. The measurements were performed at 14 days. Western blot assay was conducted to analyze TMEM16 A expression in the L4–6 dorsal root ganglion. Immunofluorescence staining was used to detect the immunoreactivity of TMEM16 A in the L4–6 dorsal root ganglion on the injured side. Patch clamp was used to detect electrophysiological changes in the neurons in the L4–6 dorsal root ganglion. Our results demonstrated that thermal withdrawal latency was shortened in the model rats compared with control rats.Additionally, TMEM16 A expression and the number of TMEM16 A positive cells in the L4–6 dorsal root ganglion were higher in the model rats, which induced excitation of the neurons in the L4–6 dorsal root ganglion. These findings were inhibited by T16 Ainh-A01 and confirm that TMEM16 A plays a key role in persistent chronic constriction injury-induced hyperalgesia. Thus, inhibiting TMEM16 A might be a novel pharmacological intervention for neuropathic pain. All experimental protocols were approved by the Animal Ethics Committee at the First Affiliated Hospital of Shihezi University School of Medicine, China(approval No. A2017-170-01) on February 27, 2017.

Differential Expression of Alpha-Adrenoceptor Subtypes in Rat Dorsal Root Ganglion after Chronic Constriction Injury

Summary： mRNAs of alpha-adrenoceptor （α-AR） subtypes are found in neurons in dorsal root ganglion （DRG） and change after peripheral nerve injury. In this study, the distribution of α-AR subtype proteins was studied in L5 DRG of normal rats and rats with chronic constriction injury of sciatic nerve （CCI）. Using immunofluorescence technique, it was found that α1A-, α1B-, and α2A-AR proteins were expressed in large, medium, and small size neurons in normal DRG, and significantly increased in all size neurons 14 days after CCI. α1D- and α2C-AR was also expressed in all size neurons in normal DRG. However, α1D-AR was significantly increased and α2C-AR was decreased in small size neurons 14 days post CCI. α2B-AR neurons were not detectable in normal and CCI DRG. Co-expression of α1A- and α2A-AR in the same neuron was observed in normal DRG and increased post CCI. Collectively, these results indicated that there is distinct distribution of α-AR subtypes in DRG neurons, and the distribution and levels of expression of α-AR subtypes change differently after CCI. The up-regulation of α-AR subtypes in DRG neurons may play an important role in the process of generating and transmitting neuropathic pain.

Effect of Touch stimulus on the Expression of C-fos and TrkA in Spinal Cord Following Chronic Constriction Injury of the Sciatic Nerve in Rats

Summary: To study the mechanism of the innoxious touch-stimulus on the modulation of hyperalgesia and the expression of the C-fos and the nerve growth factor (NGF) receptor-TrkA in the spinal dorsal horn neurons following the chronic constriction injury (CCI) of the sciatic nerve in rats, 60 female Sprague-Dawley rats were randomly divided into sham-operation group and CCI group, with each group being further divided into 3 subgroups on the 7th,14th and 28th day after operation (n=10). The mechanical and the thermal withdrawal threshold were assessed following the touch stiumulation after the CCI, immunohistochemical methods were employed to observe the expression of the C-fos and TrkA in spinal dorsal horn. Our results showed that the hyperalgesia appeared on the 4th day and reached the maximal level on the 14th day after operation. The expression of the C-fos also increased significantly and reached its maximal level on the 14th day after the touch-stimulus. Meanwhile, the TrkA expression was elevated significantly in both groups, as compared with basic data, and the difference was statistically significant (P<0.05). It is concluded that the level of the C-fos expression changed with the paw withdrawal threshold variation and increased markedly following the innoxious touch-stimulus. The expression of the TrkA receptors also increased gradually following the development of the neuropathic pain. The results suggest that C-fos may play a crucial role in the development of the hyperalgesia in the earlier-time of the neuropathic pain, but TrkA receptors may be involved in the long-lasting adaptive changes of the central pathway in neuropathic pain.

Expression and effect of sodium-potassium-chloride cotransporter on dorsal root ganglion neurons in a rat model of chronic constriction injury

Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain.We investigated whether the increase of NKCC1 and KCC2 is associated with peripheral pain transmission in dorsal root ganglion neurons.To this aim,rats with persistent hyperalgesia were randomly divided into four groups.Rats in the control group received no treatment,and the rat sciatic nerve was only exposed in the sham group.Rats in the chronic constriction injury group were established into chronic constriction injury models by ligating sciatic nerve and rats were given bumetanide,an inhibitor of NKCC1,based on chronic constriction injury modeling in the chronic constriction injury + bumetanide group.In the experiment measuring thermal withdrawal latency,bumetanide (15 mg/kg) was intravenously administered.In the patch clamp experiment,bumetanide (10 μg/μL) and acutely isolated dorsal root ganglion neurons (on day 14) were incubated for 1 hour,or bumetanide (5 μg/μL) was intrathecally injected.The Hargreaves test was conducted to detect changes in thermal hyperalgesia in rats.We found that the thermal withdrawal latency of rats was significantly decreased on days 7,14,and 21 after model establishment.After intravenous injection of bumetanide,the reduction in thermal retraction latency caused by model establishment was significantly inhibited.Immunohistochemistry and western blot assay results revealed that the immune response and protein expression of NKCC1 in dorsal root ganglion neurons of the chronic constriction injury group increased significantly on days 7,14,and 21 after model establishment.No immune response or protein expression of KCC2 was observed in dorsal root ganglion neurons before and after model establishment.The Cl^– (chloride ion) fluorescent probe technique was used to evaluate the change of Cl^– concentration in dorsal root ganglion neurons of chronic constriction injury model rats.We found that the relative optical density of N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (a Cl^– fluorescent probe whose fluorescence Cenintensity decreases as Cl– concentration increases) in the dorsal root ganglion neurons of the chronic constriction injury group was significantly decreased on days 7 and 14 after model establishment.The whole-cell patch clamp technique revealed that the resting potential and action potential frequency of dorsal root ganglion neurons increased,and the threshold and rheobase of action potentials decreased in the chronic constriction injury group on day 14 after model establishment.After bumetanide administration,the above indicators were significantly suppressed.These results confirm that CCI can induce abnormal overexpression of NKCC1,thereby increasing the Cl^– concentration in dorsal root ganglion neurons;this then enhances the excitability of dorsal root ganglion neurons and ultimately promotes hyperalgesia and allodynia.In addition,bumetanide can achieve analgesic effects.All experiments were approved by the Institutional Ethics Review Board at the First Affiliated Hospital,College of Medicine,Shihezi University,China on February 22,2017 (approval No.A2017-169-01).

Aloin attenuates chronic constriction injury-induced neuropathic pain in rats by inhibiting inflammatory cytokines and oxidative stress

Objective:To investigate the effect of aloin against chronic constriction injury(CCI)-induced neuropathic pain in rats.Methods:Rats were randomly divided into 7 groups:GroupⅠ(normal control),GroupⅡ(sham-operated),GroupⅢ(CCI control)and GroupⅣ,Ⅴ,Ⅵ,andⅦ,which underwent CCI surgery and then were administered with aloin(5 mg/kg,p.o.;25 mg/kg,p.o.;125 mg/kg,p.o.)and gabapentin(50 mg/kg,p.o.),respectively for 14 days.Peripheral neuropathy was induced by silk ligatures(4-0)loosely placed around the sciatic nerve.Nociceptive thresholds against mechanical stimuli(Von-Frey filaments)and thermal stimuli(12℃and 40℃)were measured at midplantar paw region ipsilateral to the compressed nerve on day-3,7,11,and 14.The concentration of cytokines including tumor necrosis factor-α(TNF-α),interleukin-6,and interleukin-1βwas estimated at day-7.At day 14,motor nerve conduction velocity was determined under urethane anesthesia(1.25 g/kg).Oxidative stress parameters(malondiadehyde,glutathione,catalase,and superoxide dismutase)were estimated in sciatic nerve homogenates at day 14.Representative nerve samples were processed for histological investigations.Results:Aloin significantly reduced CCI-induced mechanical and thermal allodynia.It also improved motor nerve conduction velocity and decreased oxidative stress in nerve tissues.In addition,it decreased pro-inflammatory cytokine levels and restored the histoarchitecture of compressed sciatic nerve.Conclusions:Aloin mitigates CCI-induced neuropathic pain in rats by inhibiting oxidative stress and pro-inflammatory cytokines in the afflicted sciatic nerve.

Chronic Effusive Pericarditis and Chronic Constrictive Pericarditis

Chronic Pericarditis is infl ammation that begins gradually,is long lasting and results in fl uid accumulation in the pericardial space or thickening of the pericardium.The etiology is unknown but may be cancer,TB or hypothyroidism.Arrhythmias are common and seen in almost half the patients.The commonest arrhythmia is atrial fi brillation.Symptoms and signs are related to increased right atrial pressure and physical fi ndings include elevated JVP and pericardial knock.Non surgical therapy consists mainly of no salt.Surgery cures about 85%of patients,however 5–15%of patients will die.Chronic effusive pericarditis occurs when there is persistent restriction of the visceral pericardium after pericardiocentesis.

The Primary Motor Cortex Stimulation Attenuates Cold Allodynia in a Chronic Peripheral Neuropathic Pain Condition in <i>Rattus norvegicus</i>

Background: The primary motor cortex (M1) stimulation (MCS) is a useful tool for attenuation of the peripheral neuropathic pain in patients with pharmacologically refractory pain. Furthermore, that neurological procedure may also cause antinociception in rodents with neuropathic pain. Cold allodynia is a frequent clinical finding in patients with neuropathic pain, then, we evaluated if an adapted model of neuropathy induced by chronic constriction injury (CCI) of the ischiadicus nervus (sciatic nerve) produces cold allodynia in an animal model of chronic pain. In addition, we also investigated the effect of the electrical stimulation of the M1 on chronic neuropathic pain condition in laboratory animals. Methods: Male Wistar rats were used. An adapted model of peripheral mononeuropathy induced by CCI was carried out by placing a single loose ligature around the right sciatic nerve. The acetone test was used to evaluate the cold allodynia in CCI or Sham (without ligature) rats. The MCS (M1) was performed at low-frequency (20 μA, 100 Hz) during 15 s by deep brain stimulation (DBS-Thomas Recording device) 21 days after CCI or Sham procedures. The cold allodynia was measured before and immediately after the neurostimulation of M1 in the following time-window: 0, 15 and 30 min after MCS. Results: Cold allodynia threshold increased in animals with chronic neuropathic pain submitted to the acetone test 21 days after the CCI surgery. The M1-stimulation by DBS procedure decreased the cold allodynia immediately and until 30 min after M1-stimulation in rats with chronic neuropathic pain. Conclusion: The current proposal for a CCI model by a single loose ligature of the sciatic nerve can be employed as an experimental model of chronic neuropathic pain in rats submitted to peripheral nervous system injury. The M1-stimulation produced antinociception in rats with chronic neuropathic pain. Thus, we reinforced that the MCS decreases cold allodynia in laboratory animals submitted to persistent sciatic nerve constriction and can be a more reasonable procedure for the treatment of chronic intractable neuropathic pain.

富血小板血浆凝胶缓解CCI模型大鼠周围神经痛及其改善中枢海马组织炎性机制研究

目的建立大鼠坐骨神经慢性压迫损伤(CCI)模型,观察富血小板血浆凝胶(PRP)对CCI大鼠坐骨神经病理性疼痛进展期痛域的影响,并探讨其对中枢海马组织的抗炎作用机制。方法选择SPF级雄性SD大鼠50只,其中10只用于制备PRP,其余40只采用随机数表法分为空白对照组、假手术组、CCI组和CCI+PRP组,每组10只。比较各组大鼠在术前1 d、术后6 h、1 d、3 d、7 d足底机械性缩足反射阈值(MWT)和热辐射缩足潜伏期(TWL)变化;比较术后7 d时各组大鼠海马区肿瘤坏死因子(TNF-α)、白细胞介素-1β(IL-1β)和高迁移率组蛋白1(HMGB1)及其下游Toll样受体-4(TLR4)、糖基化终产物受体(RAGE)mRNA表达水平。结果空白组与假手术组各时间点大鼠MMT和TWL比较差异均无统计学意义(P>0.05);CCI组和CCI+PRP组大鼠术后MMT和TWL值与术前比较差异均有统计学意义(P<0.05);CCI组和CCI+PRP组大鼠术后各时间点MWT和TWL比较差异均有统计学意义(P<0.05)。术后7 d时,对照组和假手术组大鼠海马组织的TNF-α、IL-1β、HMGB1含量以及HMGB1、TLR4和RAGE mRNA表达水平比较差异均无统计学意义(P>0.05),而CCI组和CCI+PRP组与对照组或假手术组比较差异均具有统计学意义(P<0.05);术后7 d时,CCI+PRP组与CCI组大鼠海马组织的TNF-α、IL-1β、HMGB1含量以及HMGB1、TLR4和RAGE mRNA表达水平比较,差异均具有统计学意义(P<0.05)。结论富血小板血浆可有效延缓CCI大鼠神经病理性疼痛进展期痛域,抑制中枢海马组织炎性反应,其机制可能与富血小板血浆通过HMGB1-TLR4/RAGE信号通路抑制TNF-α、IL-1β表达水平有关。

颅痛宁颗粒对眶下神经缩窄环术诱导三叉神经痛大鼠的治疗作用研究

目的研究颅痛宁颗粒对三叉神经痛模型大鼠的治疗作用,为其临床应用提供参考资料。方法采用眶下神经缩窄环术(ION-CCI)制备大鼠三叉神经痛模型,大鼠随机分为正常组、假手术组、模型组、卡马西平阳性药组、颅痛宁高剂量组(2.70 g生药·kg^(-1)·d^(-1))、颅痛宁低剂量组(1.35 g生药·kg^(-1)·d^(-1))。Von Frey毛刷测定大鼠触须垫机械痛阈值,生化法检测血液血流变和凝血功能,HE染色观察眶下神经病理变化,Western blot技术检测三叉神经内P38和P-P38的蛋白水平。结果颅痛宁颗粒能提高模型大鼠的痛阈值(P<0.05,P<0.01)降低模型大鼠血浆黏度(P<0.05,P<0.01)和全血还原黏度(P<0.05,P<0.01),提高模型大鼠血流变能力;提高模型大鼠血液凝血酶原时间(prothrombintime,PT)、活化部分凝血活酶时间(activated partial thromboplatin time,APTT)和凝血酶时间(thrombin time,TT)水平(P<0.05,P<0.01),降低模型大鼠纤维蛋白原(fibrinogen,FIB)水平(P<0.01),改善凝血功能;改善模型大鼠眶下神经的病理改变;并降低模型大鼠三叉神经内P-P38的表达量(P<0.01)。结论颅痛宁颗粒具有改善三叉神经痛作用,可能与其活血化瘀功能有关。

Effect of Pulsed Radiofrequency on Rat Sciatic Nerve Chronic Constriction Injury： A Preliminary Study

Background：Pulsed radiofrequency （PRF） application to the dorsal root ganglia can reduce neuropathic pain （NP） in animal models,but the effect of PRF on damaged peripheral nerves has not been examined.We investigated the effect of PRF to the rat sciatic nerve （SN） on pain-related behavior and SN ultrastructure following chronic constriction injury （CCI）.Methods：The analgesic effect was measured by hindpaw mechanical withdrawal threshold （MWT） and thermal withdrawal latency （TWL）.Twenty rats with NP induced by ligating the common SN were then randomly divided into a PRF treatment group and a sham group.The contralateral SN served as a control.The MWT and TWL were determined again 2,4,6,8,10,12,and 14 days after the PRF or sham treatment.On day 14,ipsilateral and contralateral common SNs were excised and examined by electron microscopy.Results：Ipsilateral MWT was significantly reduced and TWL significantly shorter compared to the contralateral side 14 days after CCI （both P =0.000）.In the PRF group,MWT was significantly higher and TWL significantly longer 14 days after the PRF treatment compared to before PRF treatment （both P =0.000）,while no such difference was observed in the sham group （P ＞ 0.05）.Electron microscopy revealed extensive demyelination and collagen fiber formation in the ipsilateral SN of sham-treated rats but sparse demyelination and some nerve fiber regrowth in the PRF treatment group.Conclusions：Hyperalgesia is relieved,and ultrastructural damage ameliorated after direct PRF treatment to the SN in the CCI rat model of NP.

Radial shock wave therapy in the treatment of chronic constriction injury model in rats： a preliminary study

Background Pain physicians pay close attention to neuropathic pain （NP）,since there is currently no ideal treatment.Radial shock wave therapy （RSWT） is a noninvasive treatment to chronic pain of soft tissue disorders.So far,there is no information on the use of RSWT for the treatment of NP.Therefore we observe the effects of RSWT on a NP model induced by chronic constriction injury （CCI） in rats.Methods Four different energy densities （1.0,1.5,2.0 and 2.5 bar） RSWT administered as a single session or repeated sessions in rats with NP induced by CCI of the sciatic nerve.The analgesic effect was assessed by measuring mechanical withdrawal threshold （MWT） and thermal withdrawal latency （TWL）.The safety was assessed through calculating sciatic functional index （SFI）.Results MWT and TWL increased after a single session of RSWT from day 1 to day 5 but retumed to baseline levels by day 10.Following repeated sessions of RSWT,both the MWT and TWL were significantly higher than NP group （P ＜ 0.01）for at least 4 weeks.In addition,no significant changes of SFI were observed in any groups after repeated sessions of RSWT and no increased pain or other side effects in any animals.Conclusions A single session of RSWT is rapidly effective in the treatment of CCI,but the efficacy maintained in a short period.However,repeated sessions of RSWT have prolonged efficacy.

Pulsed radiofrequency alleviated neuropathic pain by down-regulating the expression of substance P in chronic constriction injury rat model

Background:Pulsed radiofrequency(PRF),as a non-invasive treatment of neuropathic pain(NP),has been widely administered clinically.Previous studies have shown that PRF has the potential to improve hyperalgesia in animal models of NP.However,there have been few reports to clarify whether the mechanism of PRF treatment of NP involves intervention in the expression of substance P(SP).Therefore,this study administered PRF treatment to chronic constriction injury(CCI)model rats and observed the sciatic nerve mechanical pain threshold and SP expression in the spinal cord to explore the mechanism of PRF treatment.Methods:A total of 96 Sprague-Dawley rats were randomly divided into the sham-surgery-sham-treatment group(S-S group),the sham-surgery-PRF group(S-P group),the CCI-sham-treatment group(C-S group),and the CCI-PRF group(C-P group).The C-S group and the C-P group underwent sciatic nerve CCI,while the other groups received a sham operation.At 14 days after the operation,the C-P group and the S-P group were treated with PRF for 300 s.We recorded the hindpaw withdrawal threshold(HWT)and the thermal withdrawal latency(TWL)of rats in the various groups at baseline,before treatment(0 days),and at 1,7,14,and 28 days after treatment.L4 to L6 spinal cord tissues were taken before treatment(0 days)and 1,7,14,and 28 days after treatment.The transcription and translation of SP were measured by quantitative polymerase chain reaction and Western blotting,respectively.Results:The HWT and the TWL in the C-P group 28 days after PRF treatment were significantly higher than those in the C-S group(95%confidence interval[CI]:5.84–19.50,P<0.01;95%CI:2.58–8.69,P=0.01).The expression of SP in the C-P group 28 days after PRF treatment was significantly lower than that in the C-S group(95%CI:1.17–2.48,P<0.01).Conclusions:PRF may alleviate CCI-induced NP by down-regulating the expression of SP in the spinal cord of CCI model rats.

Pulsed radiofrequency inhibits expression of P2X3 receptors and alleviates neuropathic pain induced by chronic constriction injury in rats

Background:Pulsed radiofrequency (PRF) is a minimally invasive interventional technique that provides a novel and effective treatment strategy for neuropathic pain (NP).PRF is advantageous because it does not damage nerves and avoids sensory loss after treatment.At present,animal studies have demonstrated that PRF is safe and effective for relieving the NP associated with sciatic nerve damage in rats with chronic constriction injury (CCI).However,the mechanism through which this effect occurs is unknown.An increasing body of evidence shows that the expression of the P2X ligand-gated ion channel 3 (P2X3) receptor is closely related to NP;this study was to investigate whether the expression of this receptor is involved in NP relief due to PRF.Methods:A total of 36 healthy adult male Sprague-Dawley (SD) rats were randomly divided into three groups:Sham group,CCI group,and PRF group.The right sciatic nerve was ligated in CCI group and PRF group to establish a CCI model;the right sciatic nerve was separated but not ligated in Sham group.On day 14 after the operation,PRF was administered to the ligated sciatic nerve in PRF group (42℃,45 V,2 min).A non-live electrode was placed at the exposed sciatic nerve for the rats in Sham and CCI groups.The hindpaw withdrawal threshold (HWT) and thermal withdrawal latency (TWL) were measured at the right hindpaw at different time points before and after PRF or sham therapy.On day 28 after treatment,the dorsal root ganglion (DRG) and spinal dorsal horn of the right L4-6 were harvested from each group to determine the mRNA and protein levels of the P2X3 receptor.Results:On day 28 after PRF treatment,the HWT (8.33 ± 0.67 g vs.3.62 ± 0.48 g) and TWL (25.42 ± 1.90 s vs.15.10 ± 1.71 s) were significantly higher in PRF group as compared to CCI group (P < 0.05).The mRNA expression of the P2X3 receptor in the DRG in PRF group was 23.7% lower than that in CCI group (P < 0.05),in the spinal dorsal horns in PRF group was 22.7% lower than that in CCI group (P < 0.05).The protein expression of the P2X3 receptor in the DRG in PRF group was 27.8 % lower than that in CCI group (P < 0.05),in the spinal dorsal horns in PRF group was 35.6% lower than that in CCI group (P < 0.05).Conclusion:PRF possibly reduces NP in CCI rats by inhibiting the expression of the P2X3 receptor in the L4-6 DRG and spinal dorsal horns.

藁本内酯对慢性神经病理性疼痛模型小鼠的镇痛作用研究

目的:观察藁本内酯(ligustilide,LIG)对神经病理性疼痛(neuropathic pain,NP)模型小鼠疼痛的干预作用以及初步机制探索。方法:建立经典的坐骨神经保留性神经损伤(spared nerve injury,SNI)和慢性压迫性损伤(chronic constriction injury,CCI)诱导的小鼠NP模型,观察LIG单次给药(20、40、80 mg/kg,腹腔注射)以及反复多次给药(40、80 mg/kg,腹腔注射,1次/d,连续7 d)对SNI以及CCI诱导的机械性触诱发痛的影响;在LIG反复多次给药处理(40、80 mg/kg,腹腔注射,1次/d,连续7 d)末次给药的当天行SNI和CCI手术,观察LIG处理对NP的预防作用;在LIG 80 mg/kg反复给药条件下,于SNI术后第5天,ELISA法测定脊髓L4~5节段中促炎因子TNF-α、IL-1β和IL-6的含量;免疫荧光观察小胶质细胞标志物离子钙结合衔接分子1(ionized calcium binding adaptor molecule 1,IBA-1)的阳性细胞数以分析小胶质细胞激活的情况。结果:成功建立SNI和CCI诱导的小鼠NP模型,LIG单次给药与重复多次给药均能显著缓解SNI和CCI诱导的NP症状,作用至少能维持7 d,无耐受性产生倾向。在有效剂量下,LIG并不干扰动物的运动功能,说明其镇痛作用具有特异性。术前LIG反复多次给药,能预防SNI与CCI诱导的早期机械性触诱发痛,但维持时间有限(1~2 d)。LIG反复给药处理能降低SNI模型中促炎症因子TNF-α、IL-1β和IL-6的含量,抑制SNI诱导的小胶质细胞激活。结论:LIG对NP症状具有改善作用,不产生耐受性,术前反复给药对NP有一定的预防作用。LIG抗NP机制可能与其抑制神经炎症及胶质细胞的激活有关。

延胡索在三叉神经痛大鼠模型中的镇痛作用研究

目的三叉神经痛是面部三叉神经分布区的阵发性剧烈疼痛,尚无有效治愈方法,本研究探讨一种有效治疗三叉神经痛的方法为目的。方法建立三叉神经眶下支(ION)的慢性压迫性损伤(CCI)三叉神经痛大鼠模型为研究对象,评估了中药延胡索对三叉神经痛大鼠的影响。采用Westernblot方法,研究眶下神经慢性压迫性损伤后(CCI-ION)三叉神经脊束尾侧亚核(Vc)组织中大麻素CB1受体的变化。应用CB1受体拮抗剂AM251观察对延胡索作用的影响。结果给予延胡索乙素制剂(2mg/kg,腹腔注射)提高了CCI-ION大鼠模型对机械性刺激的反应阈值和截止阈值。CCI-ION可诱导位于同侧Vc组织CB1受体呈时间依赖性上调。CB1受体拮抗剂AM251对抗延胡索的效果。结论提示延胡索的镇痛作用需CB1受体参与,表明中药延胡索可能是一种有效治疗三叉神经痛的方法。

外科治疗缩窄性心包炎128例

目的总结分析128例缩窄性心包炎的外科治疗经验。方法回顾分析128例经外科手术治疗的慢性缩窄性心包炎患者的临床资料。结果本组术后早期死亡2例,死亡率1.57%,死亡原因:均为严重低心排综合征。其它并发症有:低心排综合征17例(13.2%),心律失常9例(7.02%),急性肾功能不全5例(3.9%),呼吸功能不全4例(3.1%),伤口感染3例(2.3%),术后胸内出血2例(1.6%),脑梗塞1例(0.78%)。早期1例因心包切除不彻底而复发。结论缩窄性心包炎应尽早确诊,积极手术,术中心包切除范围因病情而定,力求彻底松解病变心包,术后积极预防各种并发症的发生。

慢性缩窄性心包炎的诊断及手术治疗

目的总结分析慢性缩窄性心包炎的诊断和治疗经验。方法回顾性分析1993年1月-2006年10月96例慢性缩窄性心包炎的临床资料，男62例，女34例，年龄5～74岁，平均34岁，术前心功能Ⅱ级8例，Ⅲ级70例，Ⅳ级18例。胸骨正中切口88例，左前外侧切8例，均在全麻下行部分心包剥脱术。结果围术期死亡2例，其中术后低心排血综合征1例，术中右心房破裂出血修补失败1例，96例中有92例获得随访，心功能恢复到Ⅰ级者86例，恢复到Ⅱ级者6例。结论心包剥脱术仍是治疗此病惟一有效的方法，早期诊断、及时手术、充分合理的心包剥脱范围，正确的围术期处理是手术成功和提高远期疗效的关键。

槲皮素减轻坐骨神经慢性缩窄性损伤大鼠的神经病理性疼痛及其相关机制

目的探究槲皮素对坐骨神经慢性缩窄性损伤(chronic constriction injury,CCI)模型大鼠神经病理性疼痛的影响及其机制。方法构建CCI大鼠模型,用不同浓度槲皮素干预,通过行为学实验检测机械缩足反射阈值(MWT)和热缩足反射潜伏期(TWL),ELISA试剂盒检测大鼠脊髓中炎性因子的表达,Western blot和qRT-PCR分别检测i NOS、COX-2和Wnt3a、β-catenin的蛋白以及mRNA的表达。结果与对照组相比,模型组大鼠MWT和TWL值明显下降(P<0.05),脊髓TNF-α、IL-1β,疼痛相关分子i NOS、COX-2,WNT通路Wnt3a、β-catenin蛋白水平均显著上升(P<0.05),而槲皮素使模型组大鼠MWT和TWL值显著提高,TNF-α和IL-1β,i NOS和COX-2,Wnt3a和β-catenin水平均显著下降(P<0.05),并呈现一定的剂量依赖效应。而Wnt/β-catenin通路激活剂可阻断槲皮素对CCI大鼠的作用。结论槲皮素可能通过抑制Wnt/β-catenin通路及其下游靶分子COX-2和i NOS的表达减轻CCI大鼠的神经病理性疼痛。

辛伐他汀对大鼠神经病理性疼痛行为学和RhoA通路表达的影响

目的：观察Rho A相关细胞骨架调控信号通路在慢性坐骨神经结扎（chronic sciatic nerve constriction injury,CCI）神经病理性疼痛大鼠背根神经节激活及辛伐他汀（simvastatin）鞘内给药对该通路影响。方法：42只质量180~200 g SD雄性大鼠随机分为5组：Na？ve组（n=6）、Sham组（n=6）、CCI组（n=18）、Simvastatin组（n=6）及Rho激酶（Rho kinase,ROCK）抑制剂Y-27632组（n=6）。对大鼠行鞘内置管,于造模后7天结扎CCI组、Simvastatin组及Y-27632组大鼠单侧坐骨神经构建CCI模型,术后Simvastatin组每天鞘内注射10μl辛伐他汀（10μg/μl）,Y-27632组每天鞘内注射12μl Y-27632（4 mg/ml）,Na？ve组、Sham组、CCI组术后每天鞘内注射生理盐水10μl,连续注射7天。于CCI建模后1、3、7、14天进行动物行为学评估,观察大鼠对机械和热刺激的反应。于建模后第14天处死大鼠,取手术侧L4~6背根神经节（dorsal root ganglion,DRG）,并进行实时定量PCR观察RhoA、ROCK的m RNA表达变化,免疫荧光观察Rho A蛋白在DRG伤害性神经元中的分布及改变,以及免疫荧光强度随建模时间梯度增加,Western blot检测通路中主要因子RhoA、LIMK和cofilin蛋白水平表达的改变。结果：1 Simvastatin组大鼠给予辛伐他汀后第3天起缩足反射热辐射潜伏期、缩足反射机械刺激阈值明显高于CCI组,差异具有统计学意义（P〈0.05）;ROCK抑制剂Y-27632组大鼠缩足反射热辐射潜伏期、缩足反射机械刺激阈值给药后3天起较CCI组明显提高,差异具有统计学意义（P〈0.05）。2 CCI组大鼠DRG中Rho A、ROCK m RNA于术后第7天起表达显著增加（P〈0.05）;Rho A蛋白在背根神经节神经元中表达,CCI术后14天Rho A免疫荧光强度与Na？ve组比显著增高（P〈0.05）。3鞘内注射辛伐他汀能显著抑制通路主要因子Rho A、p-LIMK、p-cofilin的表达（P〈0.05）。结论：大鼠CCI慢性神经病理性疼痛存在Rho A/LIMK/cofilin通路的激活,辛伐他汀鞘内注射可抑制该通路的活化,为治疗神经病理性疼痛提供新的靶点。

DNA甲基转移酶类在大鼠神经病理性疼痛发病机制中的作用

目的:探索DNA甲基转移酶类(DNA methyltransferases,DNMTs)在坐骨神经慢性缩窄性损伤(chronic constriction injury,CCI)大鼠神经病理性疼痛(neuropathic pain,NPP)发病机制中的作用。方法:腰段鞘内置管成功的27只成年雄性Sprague-Dawley大鼠,随机分为假手术组+生理盐水组(sham+NS组)、CCI+NS组及CCI+5-氮杂胞苷(5-azacytidine,5-AZA)组(CCI+5-AZA组),每组9只。CCI术后第3天至第14天,sham+NS组和CCI+NS组每天鞘内注射1次NS,CCI+5-AZA组每天鞘内注射1次10μmol/L 5-AZA。分别于术前及术后第3,5,7,10,14天测定各组大鼠术侧后足机械痛阈和热痛阈。术后第14天各组大鼠于深麻醉下处死,取脊髓腰膨大,采用RT-PCR,Western印迹和免疫组织化学测定DNMT1,DNMT3a和DNMT3b的表达。结果:术后第3天至第14天,CCI+NS组的机械痛阈和热痛阈均较sham+NS组明显下降(均P<0.05)。术后第5天至第14天,CCI+5-AZA组的机械痛阈和热痛阈均较CCI+NS组明显上升(均P<0.05),但仍低于sham+NS组(均P<0.05)。DNMT1,DNMT3a和DNMT3b在大鼠脊髓腰膨大背角处有致密表达,且以胞核分布为主。术后第14天CCI+NS组的DNMT1,DNMT3a和DNMT3b表达较sham+NS组均明显上升(均P<0.05)。CCI+5-AZA组的DNMT1,DNMT3a和DNMT3b表达均较CCI+NS组明显下降(均P<0.05),但仍高于sham+NS组(均P<0.05)。结论:DNMTs在脊髓腰膨大处的表达上调很可能在CCI大鼠NPP发病机制中起重要作用。DNMTs抑制剂5-AZA可下调DNMTs的表达和缓解CCI诱导的NPP,可能成为NPP的潜在治疗药物。