人神经生长因子对糖尿病多发性神经病大鼠坐骨神经caloainⅡ的作用

目的:观察人神经生长因子(hNGF)对早期糖尿病多发性神经病(DPN)大鼠坐骨神经中calpainⅡ表达的影响。方法:用链佐星(STZ)一次性腹腔注射诱导糖尿病大鼠模型,在DPN4周(造模后4周)腹腔注射hNGF90U/(kg·d),共4周。用原位杂交和免疫组化方法观察坐骨神经calpainⅡmRNA和蛋白表达。结果:DPN8周大鼠坐骨神经calpainⅡmRNA和蛋白表达明显减少。用hNGF治疗的DPN大鼠calpainⅡmRNA和蛋白表达增加。结论:hNGF治疗能纠正早期DPN大鼠坐骨神经calpainⅡmRNA和蛋白表达异常。     

糖尿病大鼠周围神经NGF的动态表达及巴曲酶对其影响

目的探讨神经生长因子（NGF）在糖尿病周围神经病（DPN）大鼠中的动态变化规律,初步证实巴曲酶对NGF的影响并探讨其机制,为临床上治疗DPN提供理论依据。方法将大鼠腹腔注射链脲佐菌素制作实验性糖尿病模型,再分别于成模后2个月和3个月时腹腔注射巴曲酶进行干预。通过免疫组织化学和原位杂交双重检测NGF在坐骨神经中的表达。结果DM造模后2个月时坐骨神经中NGF的含量明显减少,且随时间变化有统计学差异,而巴曲酶治疗后NGF的表达明显增加。结论DPN大鼠坐骨神经中NGF表达减少可能参与DPN的发病机制。巴曲酶对DPN有保护作用,其机制可能包括对NGF的调节。     

依达拉奉对糖尿病周围神经病大鼠神经保护的机制

目的 探讨依达拉奉对糖尿病周围神经病(DPN)大鼠神经保护的机制.方法 采用链脲佐菌素(STZ)一次性腹腔注射诱导建立SD大鼠DPN模型,并随机分为对照组和治疗组(各10只);治疗组给予依达拉奉3 mg/(kg·d)腹腔注射共4周.观察摆尾温度阈值(TTT)、坐骨神经运动神经传导速度(MCV)、感觉神经传导速度(SCV);应用酶标法及免疫组化法分别检测坐骨神经半胱氨酸蛋白酶( caspase)-3和Bcl-2表达水平,并与正常组(10只)比较.结果 与正常组比较,对照组大鼠TTT明显升高,MCV和SCV明显减慢,坐骨神经caspase-3和Bcl-2表达水平明显增高(均P＜0.01);与对照组比较,治疗组大鼠TTT明显降低,MCV和SCV明显提高(均P＜0.01);坐骨神经caspase-3表达水平明显降低,Bcl-2表达水平明显增高(均P＜0.05).结论 依达拉奉可以减轻DPN大鼠坐骨神经损伤,其机制可能与其降低周围神经caspase-3表达和增强Bcl-2表达有关.     

糖尿病大鼠周围神经bFGF的动态表达及巴曲酶对其的影响

目的探讨碱性成纤维生长因子(bFGF)在糖尿病周围神经病(DPN)大鼠中的动态变化规律;观察巴曲酶对bFGF的影响及其机制,为临床上治疗DPN提供理论依据。方法将大鼠腹腔注射链脲佐菌素制作实验性糖尿病模型,分别于成模后2m和3m时腹腔注射巴曲酶进行干预。通过免疫组织化学和原位杂交双重检测bF-GF在坐骨神经中的表达。结果DM造模后2m时坐骨神经中bFGF的含量明显减少,且随时间变化有统计学差异,巴曲酶治疗后bFGF的表达明显增加。结论DPN大鼠坐骨神经中bFGF表达减少可能参与DPN的发病机制。巴曲酶对DPN有保护作用,其机制可能包括对bFGF的调节。     

糖尿病大鼠周围神经IGF-1及VEGF的动态表达及巴曲酶对其的影响

目的 探讨胰岛素样生长因子(IGF-1)及血管内皮生长因子(VEGF)在糖尿病周围神经病(DPN)大鼠中的动态变化规律及巴曲酶对IGF-1和VEGF的影响并探讨其机制,为临床治疗DPN提供理论依据.方法 大鼠腹腔注射链脲佐菌素制作实验性糖尿病模型,分别于成模后2m和3m时腹腔注射巴曲酶进行干预.通过免疫组织化学和原位杂交双重检测IGF-1及VEGF在坐骨神经中的表达.结果 DM造模后2m时坐骨神经中IGF-1及VEGF的含量均明显减少,且随时间变化有统计学差异,而巴曲酶治疗后IGF-1的表达无明显改变,VEGF的表达明显增加.结论 :DPN大鼠坐骨神经中IGF-1及VEGF表达减少可能参与DPN的发病机制,而巴曲酶对DPN的保护作用,并非通过对IGF-1的调节,其机制可能包括对VEGF的调节.     

实验性糖尿病大鼠的单纤维肌电图研究

目的:分析链脲佐菌素(STZ)诱导的糖尿病大鼠坐骨神经的神经传导速度和腓肠肌单纤维肌电图的特点,评价两种检查方法对糖尿病多发性神经病早期诊断的价值.方法:健康雄性SD大鼠经腹腔注射STZ60mg穔g-1诱导成1型糖尿病大鼠模型(糖尿病组),在注射STZ后4、6、8、10和12周进行坐骨神经神经传导检查和腓肠肌单纤维肌电...     

中枢类大麻受体拮抗剂利莫那班对2型糖尿病周围神经病变疗效的实验分析

目的 观察利莫那班对大鼠糖尿病周围神经痛变的疗效,探讨其作用机制.方法 采用链尿佐菌素(STZ)腹腔注射诱导形成糖尿病周围神经病变(DPN)模型,随机分为模型对照组、利莫那班小剂量组、利莫那班大剂量组、正常对照组.糖尿病大鼠造模成功后予利莫那班干预,开始给药24周后将模型组和正常组比较痛阈、坐骨神经传导速度.用酶联免疫吸附测定法(ELISA法)分别洲定各组大鼠血清、脊髓及坐骨神经内IL-Iβ、TNF-α的浓度.结果 利莫邢班对DNP大鼠痛阈、坐骨神经传导速度(NCV)有明显改善(P＜0.05).与对照组比较.DPN模型组大鼠的lL-Iβ、TNF-α的含量显著增高(P＜0.05),利莫那班治疗24周后.与DPN模型组比较IL-lβ、TNF-α的含量显著降低(P＜0.05).结论 利莫那班对糖尿病周围神经病变有良好的疗效,可能是通过调节自身免疫功能机制发挥作用.     

氢气抑制核因子-κB通路对糖尿病周围神经病变的保护作用

目的观察氢气对链脲霉素致糖尿病周围神经病变模型大鼠坐骨神经功能和疼痛行为学的影响,并探讨其可能的作用机制。方法腹腔注射链脲霉素(65 mg/kg)建立糖尿病大鼠模型,6周后腹腔注射富氢生理盐水(5 ml/kg),连续治疗2周后观察不同处理组大鼠坐骨神经功能和疼痛行为学变化,并检测坐骨神经炎性因子[肿瘤坏死因子α(TNFα)和白细胞介素6(IL 6)]及核因子κB(NFκB)p65亚基表达变化。结果 (1)与正常对照组相比,模型制备成功第8周时模型组大鼠体质量降低、血糖水平升高(均P=0.000);与模型组相比,氢气治疗组大鼠体质量和血糖水平无明显改善(均P>0.05)。(2)与正常对照组相比,模型制备成功第8周时模型组大鼠坐骨神经传导速度减慢、热痛阈和机械性痛阈降低(均P=0.000);而与模型组相比,氢气治疗后大鼠坐骨神经传导速度增加、热痛阈和机械性痛阈提高(均P=0.000)。(3)经氢气治疗后,大鼠坐骨神经TNFα和IL 6表达水平降低(均P=0.000),NFκB p65亚基阳性细胞数目减少(P=0.000)。结论糖尿病周围神经病变与炎症反应有关,而氢气可以通过抑制NFκB及其下游炎性因子的表达而发挥对糖尿病周围神经损害的保护作用。     

牛磺酸对糖尿病大鼠周围神经病变的保护作用

目的研究牛磺酸对糖尿病大鼠坐骨神经结构、功能以及神经生长因子mRNA表达的影响。方法54只雄性Wistar大鼠随机分为模型组、牛磺酸组和正常对照组,每组各18只。大鼠于禁食12h后,一次性腹腔注射1%链脲佐菌素诱导制备糖尿病大鼠模型;72h后尾静脉采血测定血糖水平,>16.7mmol/L者纳入实验。模型制备后第8周末于光学显微镜和电子显微镜下观察坐骨神经形态改变。同时行逆转录聚合酶链反应半定量分析神经生长因子mRNA含量;化学比色法检测血清丙二醛含量;采用MS302多媒体生物信号系统分别记录模型制备后第4周、8周时大鼠坐骨神经运动神经传导速度。结果(1)与模型组相比,牛磺酸对链脲佐菌素诱导的糖尿病大鼠的体质量和血糖水平无明显改善(P>0.05)。(2)与正常对照组相比,模型组和牛磺酸组大鼠在注射链脲佐菌素后第8周血清丙二醛水平明显升高(均P<0.01),但牛磺酸组低于模型组(P<0.01)。(3)与正常对照组相比,模型组大鼠坐骨神经运动神经传导速度在制模后第4周、8周明显减慢(均P<0.01);同期牛磺酸组与模型组间差异亦有显著性意义(均P<0.05)。(4)病理观察显示,模型组和牛磺酸组大鼠在注射链脲佐菌素后第8周均表现为明显的损伤反应,但牛磺酸组病变程度较轻。(5)与正常对照组相比,注射链脲佐菌素后第8周模型组大鼠神经生长因子mRNA表达水平显著下降(P<0.01),牛磺酸组表达水平高于模型组(P<0.01)。结论牛磺酸对糖尿病周围神经病变的防治作用不是直接通过降低血糖水平,而可能是通过有效清除自由基,减轻脂质过氧化,上调神经生长因子mRNA表达而改善神经损伤实现的。     

糖尿病周围神经病动物模型的建立、病理观察及巴曲酶保护作用研究

目的建立稳定、可靠的糖尿病周围神经病（DPN）动物模型，观察坐骨神经的病理改变及检测周围神经传导速度和血液流变性等指标，观察巴曲酶是否对DPN有保护作用。方法将大鼠腹腔注射链脲佐菌素制作实验性糖尿病模型，再分别于成模后2个月和3个月时腹腔注射巴曲酶进行干预。电镜、光镜下观察坐骨神经的病理改变，同时检测周围神经传导速度和血液流变件等指标。结果糖尿病大鼠自造模后2个月开始，周围神经传导速度明显减慢，血液粘度及血浆粘度明显升高，用巴曲酶治疗后均得以明显改善，但神经传导速度仍低于正常。血液流变学中仅低切速血液粘度随病程延长而增加，其它指标与病程无关。光镜下可见糖尿病大鼠坐骨神经纤维髓鞘密度不均匀，有斑块状密度减低区。电镜下可见糖尿病大鼠髓鞘局部增厚及板层分离，治疗后上述改变均减轻，细小神经纤维明显增生。结论腹腔注射链脲佐菌素法可建立可靠的实验性DPN动物模型，巴曲酶干预后血液流变性得以改善，周围神经病理改变得以减轻，说明巴曲酶对DPN有保护作用。     

Sericin protects against diabetes-induced injuries in sciatic nerve and related nerve cells

Sericin from discarded silkworm cocoons of silk reeling has been used in different fields, such as cosmetology, skin care, nutrition, and oncology. The present study established a rat model of type 2 diabetes by consecutive intraperitoneal injections of low-dose (25 mg/kg) streptozotocin. After intragastrical perfusion of sericin for 35 days, blood glucose levels significantly declined, and the expression of neurofilament protein in the sciatic nerve and nerve growth factor in L_4–6 spinal ganglion and anterior horn cells significantly increased. However, the expression of neuropeptide Y in spinal ganglion and anterior horn cells significantly decreased in model rats. These findings indicate that sericin protected the sciatic nerve and related nerve cells against injury in a rat type 2 diabetic model by upregulating the expression of neurofilament protein in the sciatic nerve and nerve growth factor in spinal ganglion and anterior horn cells, and downregulating the expression of neuropeptide Y in spinal ganglion and anterior horn cells.     

Effect of 4-methylcatechol on sciatic nerve growth factor level and motor nerve conduction velocity in experimental diabetic neuropathic process in rats.

This study examined the effects of 4-methylcatechol (4-MC), a nonamine catechol compound, on the neuropathic process of streptozotocin (STZ)-induced diabetic rats. 4-MC is one of the potent stimulators of nerve growth factor (NGF) synthesis at the cellular level and in cultured sciatic nerve segments of rats. Diabetic rats showed a statistically significant fall in sciatic motor nerve conduction velocity (MNCV) and a significantly reduced NGF content in the sciatic nerve (38.5 +/- 2.8% of control, P less than 0.01) during the experimental period of 4 weeks. 4-MC treatment of the diabetic rats for 4 weeks starting from the STZ injection elevated the NGF content (140% of untreated diabetic rats, P less than 0.05) and prevented the reduction in MNCV, but no effect on high blood glucose levels was seen. These findings suggest that decreased NGF levels in the sciatic nerve of the experimental diabetic rat may be involved in the development of the diabetic neuropathic process and that 4-MC, which can elevate endogenous NGF levels in vivo, may compensate for the inhibitory effect of STZ on the NGF level in progressive diabetic neuropathy.     

Altered tubulin and neurofilament expression and impaired axonal growth in diabetic nerve regeneration

Cytoskeletal protein expression in sensory neurons and sciatic nerve axonal growth were examined in type 1 diabetic BB/Wor rats after sciatic nerve crush injury. Diabetic male rats were subjected to sciatic nerve crush at 6 wk of diabetes. L4 and L5 dorsal root ganglia (DRG) mRNA expression of low and medium molecular weight neurofilaments (NF-L, NF-M), betaII- and betaIII-tubulin as well as protein expression of NF-L, NF-M, and beta-tubulin were examined at various time points following crush injury and compared with age- and sex-matched non-diabetic BB/Wor rats. Steady state mRNA expression of NF-L, NF-M, betaII- and betaIII-tubulin were decreased in diabetic DRG. NF-L and NF-M proteins were also decreased in DRG of uncrushed diabetic animals. After crush injury, betaII- and betaIII-tubulin mRNA were upregulated in control animals at day 2 and day 6, respectively, and beta-tubulin protein showed similarly increased expression after crush injury, while such upregulations did not occur in diabetic animals. Conversely, mRNA and protein expressions of NF-L, NF-M were downregulated to a lesser extent in diabetic animals compared to control rats. These changes were associated with impaired axonal elongation and caliber growth of regenerating fibers in diabetic rats. We propose that upregulation of tubulin has a negative feedback on NF expression in response to nerve injury, as seen in control rats. The absence of this upregulation in diabetic animals may impair its regulatory effect on NF expression and contribute to perturbed nerve regeneration seen in diabetic nerve.     

Early gene responses of trophic factors in nerve regeneration differ in experimental type 1 and type 2 diabetic polyneuropathies

We have previously suggested that alterations in sequential early gene responses of trophic factors (IGF-1 -->c-fos-->NGF) contribute to impaired peripheral nerve regeneration in type 1 diabetic BB/W-rats. To study the role these responses may play in type 2 diabetic nerve regeneration, BB/Z-rats were subjected to sciatic nerve crush injury. The expression of IGF-1, c-fos, NGF and the receptors p75 and IGF-1R were determined at the protein and mRNA levels in sciatic nerve distal to the crush site by immunoblotting and semi-quantitative RT-PCR. In situ hybridization was performed to assess the cellular localization of IGF-1, NGF, p75, and IGF-1R mRNA and immunohistochemistry served to localize the source of p75 and IGF-1R protein expression. The data were compared to those of type 1 diabetic BB/Wor-rats and non-diabetic controls. Increased expression of IGF-1 in Schwann cells is the first growth factor response to injury and peaked at 0.5 hours (h) in control, 2 h in type 2 rats, and 24 h in type 1 rats. IGF-1R was expressed in Schwann cells and its expression was asynchronous to IGF-1 expression in type 1 rats but remained synchronous with IGF-1 in control and type 2 animals. The expression of the immediate early proto-oncogene c-fos exhibited an initial peak at 6 h in control animals, 24 h in type 2, and 2 days (d) in type 1 animals. The initial peak of NGF expression occurred at 6 h in non-diabetic rats, 24 h in type 2, and 2 d in type 1 diabetic rats. The expression of p75 was delayed and attenuated in type 1 diabetic rats; however, in type 2 diabetic rats it was similar to that of non-diabetic rats. These data indicate that early gene responses following nerve damage are significantly less perturbed in type 2 compared to type 1 diabetes. These differences may account for the more efficient nerve regeneration seen in type 2 diabetic polyneuropathy.     

Epalrestat protects against diabetic peripheral neuropathy by alleviating oxidative stress and inhibiting polyol pathway

Epalrestat is a noncompetitive and reversible aldose reductase inhibitor used for the treatment of diabetic neuropathy. This study assumed that epalrestat had a protective effect on diabetic peripheral nerve injury by suppressing the expression of aldose reductase in peripheral nerves of diabetes mellitus rats. The high-fat and high-carbohydrate model rats were established by intraperitoneal injection of streptozotocin. Peripheral neuropathy occurred in these rats after sustaining high blood glucose for 8 weeks. At 12 weeks after streptozotocin injection, rats were intragastrically administered epalrestat 100 mg/kg daily for 6 weeks. Transmission electron microscope revealed that the injuries to myelinated nerve fibers, non-myelinated nerve fibers and Schwann cells of rat sciatic nerves had reduced compared to rats without epalrestat administuation. Western blot assay and immunohistochemical results demonstrated that after intervention with epalrestat, the activities of antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase gradually increased, but aldose reductase protein expression gradually diminished. Results confirmed that epalrestat could protect against diabetic peripheral neuropathy by relieving oxidative stress and suppressing the polyol pathway.     

巴曲酶对实验性糖尿病大鼠周围神经传导速度的影响

目的探讨巴曲酶对糖尿病大鼠周围神经传导速度的作用。方法用链脲佐菌素一次性腹腔注射诱导糖尿病大鼠模型,在造模后2月和3月时腹腔注射巴曲酶8Bu/(kg·d),10d后测定坐骨神经运动及感觉神经传导速度。结果糖尿病大鼠在造模后2月和3月时周围神经传导速度明显减慢;用巴曲酶治疗的糖尿病大鼠周围神经传导速度明显加快。结论巴曲酶治疗能纠正糖尿病大鼠周围神经传导速度的异常。     

Heme oxygenase-1 inhibits neuropathic pain in rats with diabetic mellitus

A diabetes mellitus model was established through single intraperitoneal injection of streptozotocin into rats. Seven days later, model rats were intraperitoneally administered zinc protoporphyrin, a heme oxygenase-1 inducer, and cobalt protoporphyrin, a heme oxygenase-1 inhibitor, once every two days, for 5 successive weeks. After administration, the paw withdrawal mechanical threshold of diabetic mellitus rats significantly decreased, the myelin sheath of the sciatic nerve thickened or showed vacuole defects, the number of spinal dorsal horn neurons reduced, some neurons degenerated and were necrotic, and heme oxygenase-1 was visible in the cytoplasm of spinal dorsal horn neurons. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling demonstrated that the number of apoptotic neurons increased, which could be inhibited by cobalt protoporphyrin, however, zinc protoporphyrin led to an opposite effect. Our experimental findings indicate that heme oxygenase-1 attenuates neuropathic pain in diabetic mellitus rats through ame- lioration of peripheral neuropathy and inhibition of spinal dorsal horn neuron apoptosis.     

巴曲酶对糖尿病周围神经病大鼠血液流变性的影响

目的探讨巴曲酶对糖尿病周围神经病大鼠血液流变性的作用。方法用链尿佐菌素一次性腹腔注射诱导糖尿病大鼠模型,在造模后2月和3月时腹腔注射巴曲酶8Bu/(kg·d),10d后测定坐骨神经运动及感觉神经传导速度;然后取血测定其血液流变学指标。结果糖尿病大鼠在造模后2月和3月时周围神经传导速度明显减慢,血液流变学指标明显增加,用巴曲酶治疗后均明显改善。结论巴曲酶治疗糖尿病周围神经病的机制之一可能为改善其血液流变学。     

Impaired peripheral nerve regeneration in type‐2 diabetic mouse model

Peripheral neuropathy is one of the most common and serious complications of type‐2 diabetes. Diabetic neuropathy is characterized by a distal symmetrical sensorimotor polyneuropathy, and its incidence increases in patients 40 years of age or older. In spite of extensive research over decades, there are few effective treatments for diabetic neuropathy besides glucose control and improved lifestyle. The earliest changes in diabetic neuropathy occur in sensory nerve fibers, with initial degeneration and regeneration resulting in pain. To seek its effective treatment, here we prepared a type‐2 diabetic mouse model by giving mice 2 injections of streptozotocin and nicotinamide and examining the ability for nerve regeneration by using a sciatic nerve transection‐regeneration model previously established by us. Seventeen weeks after the last injection, the mice exhibited symptoms of type‐2 diabetes, that is, impaired glucose tolerance, decreased insulin level, mechanical hyperalgesia, and impaired sensory nerve fibers in the plantar skin. These mice showed delayed functional recovery and nerve regeneration by 2 weeks compared with young healthy mice and by 1 week compared with age‐matched non‐diabetic mice after axotomy. Furthermore, type‐2 diabetic mice displayed increased expression of PTEN in their DRG neurons. Administration of a PTEN inhibitor at the cutting site of the nerve for 4 weeks promoted the axonal transport and functional recovery remarkably. This study demonstrates that peripheral nerve regeneration was impaired in type‐2 diabetic model and that its combination with sciatic nerve transection is suitable for the study of the pathogenesis and treatment of early diabetic neuropathy.