Different Expressions of Protein Kinase C-α,βI and βII in Glomeruli of Diabetic Nephropathy Patients

In current study, the expressions of protein kinase C （PKC）-α, βⅠ and βⅡ as well as their correlation to the expression of transforming growth factor-βⅠ （TGF-βⅠ） and vascular endothelial growth factor （VEGF） were investigated in glomeruli of normal renal tissues taken from human kidney tumors and kidney tissues from patients with diabetic nephropathy （DN）. The accumulation of glomerular extracelluar matrix （ECM） was determined by PAS staining, the expressions of PKC-α, PKC-βⅠ, PKC-βⅡ, TGF-βⅠ and VEGF were measured by semi-quantitative immunohistochemistry. Our results showed that in glomeruli of normal renal tissues, PKC-α and βⅡ had a strong expression whereas the expression of PKC-βⅠ was weak; in glomeruli of DN patients, the expressions of PKC-α, PKC-βⅠ, VEGF and TGF-βⅠ and the accumulation of ECM increased significantly, but the expression of PKC-βⅡ decreased markedly. Meanwhile, the expressions of PKC-α and βⅠ had a positive correlation to the expressions of VEGF and TGF-βⅠ respectively, whereas PKC-βⅡ showed no correlation to VEGF and TGF-βⅠ. It is concluded that the expressions of PKC-α, βⅠ and βⅡ in glomeruli of normal subjects and DN patients are different. PKC-α seems to play a critical role in human DN by up-regulating VEGF expression, whereas PKC-βⅠ is relatively important for the up-regulation of TGF-βⅠ and the accumulation of ECM under diabetic conditions.

Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy

Diabetic peripheral neuropathy is a common complication of diabetes mellitus.Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies.However,existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research.Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy,it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods.This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods.Various metabolic mechanisms(e.g.,polyol,hexosamine,protein kinase C pathway)are associated with diabetic peripheral neuropathy,and researchers are looking for more effective treatments through these pathways.

Contractile apparatus dysfunction early in the pathophysiology of diabetic cardiomyopathy

Diabetes mellitus significantly increases the risk of cardiovascular disease and heart failure in patients.Independent of hypertension and coronary artery disease,diabetes is associated with a specific cardiomyopathy,known as diabetic cardiomyopathy(DCM).Four decades of research in experimental animal models and advances in clinical imaging techniques suggest that DCM is a progressive disease,beginning early after the onset of type 1 and type 2 diabetes,ahead of left ventricular remodeling and overt diastolic dysfunction.Although the molecular pathogenesis of early DCM still remains largely unclear,activation of protein kinase C appears to be central in driving the oxidative stress dependent and independent pathways in the development of contractile dysfunction.Multiple subcellular alterations to the cardiomyocyte are now being highlighted as critical events in the early changes to the rate of force development,relaxation and stability under pathophysiological stresses.These changes include perturbed calcium handling,suppressed activity of aerobic energy producing enzymes,altered transcriptional and posttranslational modification of membrane and sarcomeric cytoskeletal proteins,reduced actin-myosin cross-bridge cycling and dynamics,and changed myofilament calcium sensitivity.In this review,we will present and discuss novel aspects of the molecular pathogenesis of early DCM,with a special focus on the sarcomeric contractile apparatus.

Diabetes and high-glucose could upregulate the expression of receptor for activated C kinase 1 in retina

BACKGROUND Diabetic retinopathy(DR)is a major ocular complication of diabetes mellitus,leading to visual impairment.Retinal pigment epithelium(RPE)injury is a key component of the outer blood retinal barrier,and its damage is an important indicator of DR.Receptor for activated C kinase 1(RACK1)activates protein kinase C-ε(PKC-ε)to promote the generation of reactive oxygen species(ROS)in RPE cells,leading to apoptosis.Therefore,we hypothesize that the activation of RACK1 under hypoxic/high-glucose conditions may promote RPE cell apoptosis by modulating PKC-ε/ROS,thereby disrupting the barrier effect of the outer blood retinal barrier and contributing to the progression of DR.AIM To investigate the role and associated underlying mechanisms of RACK1 in the development of early DR.METHODS In this study,Sprague-Dawley rats and adult RPE cell line-19(ARPE-19)cells were used as in vivo and in vitro models,respectively,to explore the role of RACK1 in mediating PKC-εin early DR.Furthermore,the impact of RACK1 on apoptosis and barrier function of RPE cells was also investigated in the former model.RESULTS Streptozotocin-induced diabetic rats showed increased apoptosis and upregulated expression of RACK1 and PKC-εproteins in RPE cells following a prolonged modeling.Similarly,ARPE-19 cells exposed to high glucose and hypoxia displayed elevated mRNA and protein levels of RACK1 and PKC-ε,accompanied by an increases in ROS production,apoptosis rate,and monolayer permeability.However,silencing RACK1 significantly downregulated the expression of PKC-εand ROS,reduced cell apoptosis and permeability,and protected barrier function.CONCLUSION RACK1 plays a significant role in the development of early DR and might serve as a potential therapeutic target for DR by regulating RPE apoptosis and barrier function.

PKC-α介导的线粒体功能障碍在妊娠糖尿病致胚胎神经管缺陷中的机制研究

目的:探讨蛋白激酶C-α(PKC-α)介导的线粒体功能障碍在妊娠糖尿病致胚胎神经管缺陷(NTD)中的作用。方法:将雌性C57BL/6J小鼠随机分为对照组、NTD组、NTD+sh-PKC-α组,每组6只。除对照组外,NTD组、NTD+sh-PKC-α组建立糖尿病胚胎病小鼠模型。NTD+sh-PKC-α组分别在胚胎第1天(E1)、第4天(E4)和第8天(E8)时,经尾静脉向小鼠注射100μL携带sh-PKC-α的慢病毒(1×10^(8) TU/mL)。在第11.5天(E11.5)时,从子宫中解剖出胚胎进行分析。采用透射电子显微镜观察神经管中线粒体。采用蛋白免疫印迹法(Western Blot)分析胚胎神经管中PKC-α、抗微管相关蛋白1轻链3(LC3)和抗溶酶体相关膜蛋白2(LAMP2)蛋白表达。体外构建PKC-α敲低C17.2小鼠神经干细胞,并在低(5 mmol/L)或高(25 mmol/L)葡萄糖条件下培养,采用免疫荧光染色检测细胞自噬体变化情况。结果:在NTD组中,胚胎神经管中线粒体肿胀,嵴消失。与对照组相比,NTD组胚胎神经管中LC3Ⅱ和LAMP2蛋白表达降低(P<0.05),PKC-α蛋白表达上调(P<0.01)。通过沉默小鼠胚胎神经管中PKC-α表达,胚胎中LC3Ⅱ和LAMP2蛋白表达增加(P<0.05)。此外,NTD+sh-PKC-α组小鼠胚胎中的NTD发生率低于NTD组(P<0.01)。在高糖条件下,C17.2神经干细胞中LC3Ⅱ、LAMP2蛋白表达水平和Cyto-ID染色点的数量均低于正常葡萄糖条件下水平(P<0.05)。PKC-α蛋白敲低增加了高糖条件下的LC3Ⅱ、LAMP2蛋白表达水平和Cyto-ID染色点的数量(P<0.05)。结论:PKC-α介导的线粒体功能障碍与母体糖尿病诱导的NTD胚胎相关,通过沉默母体PKC-α减弱了神经管自噬抑制导致的NTD形成。

Role of endoplasmic reticulum stress in the loss of retinal ganglion cells in diabetic retinopathy

Endoplasmic reticulum stress is closely involved in the early stage of diabetic retinopathy. In the present study, a streptozotocin-induced diabetic animal model was given an intraperitoneal injection of tauroursodeoxycholic acid. Results from immunofluorescent co-localization experiments showed that both caspase-12 protein and c-Jun N-terminal kinase 1 phosphorylation levels significantly in- creased, which was associated with retinal ganglion cell death in diabetic retinas. The C/ERB ho- mologous protein pathway directly contributed to glial reactivity, and was subsequently responsible for neuronal loss and vascular abnormalities in diabetic retinopathy. Our experimental findings in- dicate that endoplasmic reticulum stress plays an important role in diabetes-induced retinal neu- ronal loss and vascular abnormalities, and that inhibiting the activation of the endoplasmic reticulum stress pathway provides effective protection against diabetic retinopathy.

Effect of Calcium Dobesilate on Nephropathy in Type 2 Diabetic Rats

In order to investigate the effects and mechanisms of calcium dobesilate on renal lesions in experimental type 2 diabetic rats, dibetic rats were randomly divided into control group (group C) and experimental group (group D) treated with calcium dobesitate. The serum creatinine (Scr), protein kinase C (PKC), creatinine clearance (Ccr), transforming growth factor-beta 1 (TGF-β 1), type Ⅳ collagen were compared among the groups after 24 weeks. The renal tissues were observed under light microscopy and electron microscopy. The results showed that after 24 weeks, Scr, PKC, TGF-β 1 in group D were significantly lower than in group C, meanwhile, renal pathologic changes in group D were improved. Ccr had no difference between group C and group D. It was concluded that calcium dobesilate could ameliorate renal lesions in diabetic rats through inhibiting PKC and TGF-β 1.

New treatments for diabetic macular edema

This work comprehensively reviews the latest treatment options for diabetic macular edema(DME) used in its management and presents further work on the topic.Diabetic retinopathy is an important and increasingly prevalent cause of preventable blindness worldwide. To meet this increasing burden there has recently been a proliferation of pharmacological therapies being used in clinical practice. A variety of medical treatment options now exist for DME. These include non-steroidal antiinflammatory drugs such as nepafenac, as well as intravitreal steroids like triamcinolone(kenalog). Longterm results up to 7 years after commencing treatment are presented for triamcinolone. Studies are reviewed on the use of dexamethasone(ozurdex) and fluocinolone(Retisert and Iluvien implants) including the FAME studies. A variety of anti-vascular endothelial growth factor(anti-VEGF) agents used in DME are considered in detail including ranibizumab(lucentis) and the RESTORE, RIDE, RISE and Diabetic Retinopathy Clinical Research Network(DRCR.net) studies. Bevacizumab(avastin) and pegaptinib(macugen) are also considered. The use of aflibercept(eylea) is reviewed including the significance of the DA VINCI, VISTA-DME, VIVIDDME and the DRCR.net studies which have recently suggested potentially greater efficacy when treating DME for aflibercept in patients with more severely reduced visual acuity at baseline. Evidence for the antiVEGF agent bevasiranib is also considered. Studies of anti-tumour necrosis factor agents like infliximab are reviewed. So are studies of other agents targeting inflammation including minocycline, rapamycin(sirolimus) and protein kinase C inhibitors such as midostaurin and ruboxistaurin. The protein kinase C β inhibitor Diabetic Macular Edema Study is considered. Other agents which have been suggested for DME are discussed including cyclo-oxygenase-2 inhibitors like celecoxib, phospholipase A2 inhibitors, recombinant erythropoietin, and monoclonal anti-interleukin antibodies such as canakinumab. The management of DME in a variety of clinical scenarios is also discussed- in newly diagnosed DME, refractory DME including after macular laser, and postoperatively after intraocular surgery. Results of long-term intravitreal triamcinolone for DME administered up to seven years after commencing treatment are considered in the context of the niche roles available for such agents in modern management of DME. This is alongside more widely used treatments available to the practitioner such as anti-VEGF agents like aflibercept(Eylea) and ranibizumab(Lucentis) which at present are the mainstay of pharmacological treatment of DME.

Increased expression of receptor for advanced glycation end-products worsens focal brain ischemia in diabetic rats

A rat model of diabetes mellitus was induced by a high fat diet, followed by focal brain ischemia induced using the thread method after 0.5 month. Immunohistochemistry showed that expression of receptor for advanced glycation end-products was higher in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Western blot assay revealed increased phosphorylated c-Jun N-terminal kinase expression, and unchanged phosphorylated extracellular signal-regulated protein kinase protein expression in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Additionally, phosphorylated p38 mitogen-activated protein kinase protein was not detected in any rats in the two groups. Severity of limb hemiplegia was worse in diabetic rats with brain ischemia compared with ischemia alone rats. The results suggest that increased expression of receptor for advanced glycation end-products can further activate the c-Jun N-terminal kinase pathway in mitogen-activated protein kinase, thereby worsening brain injury associated with focal brain ischemia in diabetic rats.

Bitter gourd extract improves glucose homeostasis and lipid profile via enhancing insulin signaling in the liver and skeletal muscles of diabetic rats

Objective:To investigate the modulatory effects of bitter gourd extract on the insulin signaling pathway in the liver and skeletal muscle tissues of diabetic rats.Methods:The ethanolic extract of bitter gourd was prepared and its contents of total polyphenols and flavonoids were assayed.A neonatal streptozotocin-induced diabetic rat model was established and the diabetic rats were assigned into different groups and were treated with different doses of bitter gourd extract(100,200,400,or 600 mg/kg)or with glibenclamide(0.1 mg/kg)for 30 d.Fasting blood glucose,insulin,and lipid profile were evaluated and the insulin signaling pathway in the liver and skeletal muscle of rats was investigated.The correlations between homeostasis model assessment(HOMA)and the components of insulin signaling pathway were also evaluated.Results:Different doses of bitter gourd extract significantly ameliorated fasting blood glucose level and HOMA index for insulin resistance.Moreover,bitter gourd extract increased serum insulin and improved disrupted serum lipid profile.The levels of insulin receptor substrate-1(IRS-1),p-insulin receptorβ(p-IR-β),protein kinase C(PKC),GLUT2,and GLUT4 were improved by treatment with bitter gourd extract.The best results were obtained with 400 mg/kg dose of the extract,the effect of which was equivalent to that of glibenclamide.HOMA in the bitter gourd treated rats was negatively correlated with p-IR-β,IRS-1 and PKC in hepatic and skeletal muscle.HOMA was also negatively correlated with skeletal muscle GLUT4.Conclusions:Bitter gourd extract improves glucose homeostasis and lipid profile in diabetic rats via enhancement of insulin secretion and sensitivity.Therefore,bitter gourd can be used as a potential pharmacological agent for the treatment of type 2 diabetes mellitus.

大蒜素对2型糖尿病大鼠肾脏AGEs/PKC/p66shc通路的影响

目的以腹腔注射链脲佐菌素(streptozotocin,STZ)建立2型糖尿病肾病大鼠模型,探究大蒜素对2型糖尿病大鼠肾脏的保护作用及其机制。方法将30只SD雄性大鼠正常对照组(Control)、糖尿病肾病模型组(Model)、低剂量大蒜素保护组(DT10)、中剂量大蒜素保护组(DT20)、高剂量大蒜素保护组(DT40)5组,利用试剂盒检测肌酐、微量白蛋白、丙二醛的水平以及超氧化物歧化酶的活性。HE、PAS染色观察大鼠肾脏形态学变化。Western Blot检测相关蛋白的表达。结果与模型组相比,大蒜素保护组的肌酐、微量白蛋白、丙二醛的水平明显下降(P<0.05),超氧化物歧化酶的活性明显升高(P<0.05)。HE、PAS染色结果显示,肾组织显微结构改善、肾间质糖原沉积物减少。Western Blot结果显示,与模型组相比,大蒜素保护组的AGEs、p-PKC、p66shc的水平明显降低(P<0.05)。结论大蒜素对糖尿病大鼠肾脏具有一定的保护作用,这种保护作用的机制可能与其调控AGEs/PKC/p66shc信号通路有关。

Ginsenoside Rb1 alleviates chronic intermittent hypoxia-induced diabetic cardiomyopathy in db/db mice by regulating the adenosine monophosphate-activated protein kinase/Nrf2/heme oxygenase-1 signaling pathway

OBJECTIVE:To examine the protective effect of ginsenoside Rb1(Rb1),the main component of Renshen(Radix Ginseng),on cardiomyopathy in db/db mice exposed to chronic intermittent hypoxia(CIH)and explore the potential underlying mechanism of Rb1 in treating diabetic cardiomyopathy(DCM).METHODS:The db/db mice were randomly separated into five groups:normal control group,model group,Rb120 mg/kg group,Rb140 mg/kg group,and glucagon-like peptide-1(GLP-1)group.Mice were exposed to aircondition or CIH for 8 weeks,and Rb1 and GLP-1 were administrated before CIH exposure every day.Oral glucose tolerance test(OGTT),intraperitoneal insulin tolerance test(IPITT),total cholesterol(TC),triglyceride(TG),and high-density lipoprotein cholesterol(HDL-C)were detected to evaluate glycolipid metabolism.The level of insulin was detected by a mouse enzyme-linked immunosorbent assay(ELISA).Cardiac function was detected by echocardiography,and myocardial pathology was observed by hematoxylin-eosin and Masson staining.The expression of collagenⅠand collagenⅢwas detected by immunohistochemistry.Adenosine monophosphate-activated protein kinase(AMPK)/Nrf2/heme oxygenase-1(HO-1)signaling pathway was detected by Western blot and immunofluorescence.RESULTS:Rb1 treatment could improve glucose tolerance and the level of cardiac function indexes,and inhibit the level of oxidative stress indexes and the expression of collagenⅠand collagenⅢ.Moreover,Rb1 treatment enhanced AMPK phosphorylation and increased Nrf2 and HO-1 expression.CONCLUSION:Rb1 treatment alleviated CIH-induced diabetic cardiomyopathy and glycolipid metabolism disorders in db/db mice by inhibiting oxidative stress and regulating the AMPK/Nrf2/HO-1 signaling pathway.

菟箭合剂对糖尿病大鼠肾组织蛋白激酶C活性作用的研究

目的 :观察菟箭合剂对实验性糖尿病肾病大鼠肾组织蛋白激酶C(PKC)活性、肾功能及肾脏结构的影响。方法 :单肾切除加链脲佐菌素 (STZ)腹腔注射制作糖尿病肾病动物模型。中药菟箭合剂 (2 0g·kg-1·d-1)和阳性对照药缬沙坦 (2 0mg·kg-1·d-1)干预治疗 12周 ,用氚标记的二丁酸佛波醇酯 ([3 H]PDBu)结合法测定大鼠肾组织PKC活性 ,检测 2 4h尿蛋白排出量 (Upro) ,肾脏常规染色光镜观察病理变化。结果 :12周时单肾糖尿病大鼠肾组织出现肾小球硬化病理改变 ,Upro明显升高 ,细胞膜PKC活性 (mPKC)明显升高 ,细胞浆PKC活性 (cPKC)明显降低 ,mPKC和cPKC比值 (M/C)明显升高。菟箭合剂和缬沙坦干预治疗显著降低Upro ,降低mPKC和M/C ,升高cPKC(P <0 .0 1) ,改善肾组织病理改变。结论 :菟箭合剂对单肾切除STZ糖尿病大鼠具有肾保护作用 ,推测部分地通过抑制肾组织PKC激活途径来达到的。

厄贝沙坦对2型糖尿病大鼠肾脏氧化应激和蛋白激酶C活性的影响

目的 :探讨厄贝沙坦对 2型糖尿病大鼠肾脏氧化应激 (OS)和蛋白激酶C(PKC)活性的影响。方法 :将实验动物分为正常对照组、糖尿病组及厄贝沙坦治疗组。检测各组第 4 ,5 ,11,17周的血糖、血胰岛素、血脂 (TG、TC) ,11,17周的血肌酐 (Scr)、血尿素氮 (BUN)、尿微白蛋白排泄率 (UAE)、肾组织中丙二醛 (MDA)含量、铜 ,锌 超氧化物歧化酶 (Cu ,Zn SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化酶 (GSH Px)及PKC活性。结果 :与糖尿病组相比 ,厄贝沙坦治疗组血糖、血胰岛素及血脂无明显变化。而Scr、BUN、UAE、肾脏MDA含量、肾细胞膜PKC均明显下降 ,肾脏抗氧化酶活性 (Cu ,Zn SOD、CAT、GSH Px)则明显上升。作相关性分析发现肾脏内MDA含量的变化及抗氧化酶活性的变化与细胞膜、细胞浆PKC活性的变化相关。结论 :厄贝沙坦可以抑制 2型糖尿病大鼠肾脏内的氧化应激 ,并且这种抑制作用与其下调蛋白激酶C活性有关。

钒酸盐纠正了糖尿病大鼠心肌组织内活化的DAG-PKC信息传导

自的探讨糖尿病大鼠心肌细胞内信息传导与心功能降低的关系。方法检测糖尿病大鼠心肌二酞基甘油（DAG）含量、蛋白激酶C（PKC）活性和心功能变化及胃饲钒酸钠（SV）的影响。结果糖尿病大鼠心肌DAG含量和胞膜PKC活性显著升高，心功能显著降低，胃饲SV后明显改善。结论DAG-PKC通路激活是形成糖尿病性心肌病的一个重要发病机制。

三七多糖调控蛋白激酶C-η及蛋白激酶C-ζ表达改善2型糖尿病大鼠肾功能的研究

目的探讨三七多糖干预2型糖尿病大鼠后大鼠肾脏病理学、肾功能、血糖、蛋白激酶C-η(PKC-η)及蛋白激酶C-ζ(PKC-ζ)的特点。方法 100只雄性Sprague-Dawley大鼠随机分为空白对照组,模型组及三七多糖低、中、高剂量组,每组20只。模型组及三七多糖低、中、高剂量组大鼠给予高脂高糖饮食6个月建立2型糖尿病大鼠模型,模型建立成功后三七多糖低、中、高剂量组大鼠分别给予三七多糖28.5、57.0、114.0 mg·kg-1·d-1灌胃治疗,模型组大鼠给予10 m L·kg-1·d-1生理盐水灌胃,空白对照组大鼠不给予任何干预。治疗4周和8周后各组分别处死大鼠各半,苏木精-伊红(HE)染色检测肾脏病理学变化,试剂盒检测肾功能及血糖水平,半定量聚合酶链反应检测肾脏组织中PKC-ηmRNA和PKC-ζmRNA的表达。结果 HE染色可见空白对照组大鼠肾小管清晰无任何损伤,而模型组大鼠肾小管有炎症反应,但肾小球病变不明显,治疗4、8周后,三七多糖低、中、高剂量组大鼠肾小管逐步缩小,细胞趋于致密。治疗4周后,三七多糖低、中、高剂量组大鼠血尿素氮水平与模型组比较显著降低(P<0.05),治疗8周后进一步降低(P<0.05);治疗8周后三七多糖中、高剂量组大鼠血尿素氮水平与空白对照组比较差异无统计学意义(P>0.05)。治疗4、8周后,三七多糖低、中、高剂量组大鼠血肌酐、血尿酸、血糖水平与模型组和空白对照组比较显著降低(P<0.05);三七多糖低、中、高剂量组大鼠血尿素氮、血肌酐、血尿酸及血糖水平比较差异无统计学意义(P>0.05)。治疗4、8周后,三七多糖低、中、高剂量组大鼠PKC-ηmRNA和PKC-ζmRNA的表达显著低于模型组(P<0.05)。治疗4周后三七多糖高剂量组大鼠PKC-ζmRNA表达与空白对照组比较差异无统计学意义(P>0.05);治疗8周后,三七多糖高剂量组大鼠PKC-ζmRNA表达显著低于空白对照组(P<0.05)。治疗4周后,三七多糖高剂量组大鼠PKC-ηmRNA及PKC-ζmRNA表达显著低于三七多糖低剂量组(P<0.05);治疗8周后,三七多糖中、高剂量组大鼠PKC-ηmRNA表达显著低于三七多糖低剂量组(P<0.05)。结论三七多糖可调节大鼠血脂,进而改善2型糖尿病大鼠肾功能,这可能与肾脏中PKC-η和PKC-ζ表达降低有关。

牛蒡子提取物对糖尿病大鼠肾脏蛋白激酶C活性作用的研究

目的 :研究糖尿病大鼠肾皮质蛋白激酶C(PKC)活性的变化及牛蒡子提取物对其影响 ,探讨牛蒡子粗粉及提取物治疗糖尿病肾病的作用机制。方法 :采用链脲佐菌素 (STZ)腹腔注射造成糖尿病肾病大鼠模型 ,给予牛蒡子粗粉及提取物灌胃治疗 6周 ,检测其体重、肾重 体重、尿量、尿微量白蛋白、肾皮质PKC活性变化。结果 :经牛蒡子粗粉及提取物治疗后 ,糖尿病大鼠尿量、肾重 体重、尿白蛋白均有明显减少 ,与模型组相比 ,有明显差异 (P <0 0 5 )。可降低胞膜PKC活性 ,与模型组相比 ,有明显差别 (P <0 0 5 )。结论 :牛蒡子提取物降低胞膜PKC活性 ,可能为其对肾脏保护作用的机制之一。表明

葛根素对糖尿病大鼠肾脏蛋白激酶C活性的作用

目的 研究葛根素(Pue)对糖尿病大鼠肾脏蛋白激酶C(PKC)活性、肾功能及肾脏结构的影响。方法链脲佐菌素(STZ)诱导糖尿病大鼠模型,随机分为糖尿病组、Pue(500、250、125 mg/kg)治疗组、维生素E(VitE)组,同时另设正常对照组,给药12周后,测定肾功能及肾脏指数,ELISA法测定肾脏PKC活性,放免法测定尿蛋白排泄率,并对肾组织进行光镜及电镜观察。结果 糖尿病大鼠尿白蛋白排泄率、肾脏指数(肾脏质量/体重)、肾小球细胞膜PKC活性明显升高,给予Pue治疗12周后,治疗组糖尿病大鼠尿白蛋白排泄率较糖尿病组显著降低,肾脏肥大也有明显改善,肾小球细胞膜PKC活性显著下降,光镜及电镜下肾脏病理改变较糖尿病组有较大改善。结论 Pue可以纠正糖尿病大鼠早期肾脏高滤过、高灌注,并对糖尿病大鼠肾脏病变有一定的保护作用,其部分机制可能是通过下调肾脏PKC活性而实现的。

蛋白激酶C抑制剂Ro-31-8220逆转高糖诱导乳鼠心肌细胞肥大的作用及其相关机制

目的:观察蛋白激酶C(PKC)抑制剂Ro-31-8220对高糖诱导的乳鼠心肌细胞肥大的影响,并初步探讨PKC及其下游信号转导途径在其中的作用机制。方法:建立乳鼠心肌细胞培养模型,随机分成对照组(5.5mmol.L-1)、不同浓度高糖组(10mmol.L-1、15mmol.L-1、20mmol.L-1、25.5mmol.L-1)、高糖(25.5mmol.L-1)+PKC抑制剂Ro-31-8220组(50nmol.L-1)和高糖(25.5mmol.L-1)+NF-κB抑制剂BAY11-7082(5mmol.L-1)组,分别测定各组乳鼠心肌细胞直径和蛋白质含量,并应用Westernblotting检测乳鼠心肌细胞PKC-α、PKC-β2、p-PKC-α、p-PKC-β2、NF-κB和c-Fos等蛋白的表达水平。结果:高糖可以明显诱导乳鼠心肌细胞肥大,提高乳鼠心肌细胞PKC-α、PKC-β2、p-PKC-α、p-PKC-β2、NF-κB和c-Fos的蛋白表达,与对照组相比差异显著(P<0.01),并呈现一定的浓度依赖性;而Ro-31-8220能够逆转上述现象,其细胞直径和蛋白表达低于高糖组,并有显著差异(P<0.01)。结论:高糖能够浓度依赖性地诱导心肌细胞肥大,而PKC抑制剂Ro-31-8220则能抑制高糖所诱导的这种反应,其机制可能与PKC/NF-κB/c-Fos途径相关。

芪灯明目胶囊对自发性糖尿病大鼠视网膜蛋白激酶C表达的影响

目的观察芪灯明目胶囊对自发性糖尿病大鼠(GK大鼠)视网膜蛋白激酶C(pro-tein kinase C,PKC)表达的影响,探讨中医药治疗糖尿病视网膜病变的机制。方法从形态学等方面对GK大鼠模型进行评价。选取GK大鼠模型78只,随机分为6组:阴性对照组,芪灯明目胶囊低、中、高剂量组,递法明组及导升明组,每组各13只;另设10只Wistar大鼠为正常对照组。连续灌胃3个月,并于灌胃3个月后处死大鼠,通过免疫组织化学方法,观察芪灯明目胶囊对GK大鼠视网膜PKC蛋白表达的影响。结果经芪灯明目胶囊治疗3个月的大鼠体毛较以前洁净有光泽,活泼好动。正常对照组、阴性对照组、芪灯明目胶囊低、中、高剂量组、递法明组和导升明组大鼠视网膜PKC蛋白表达的灰度值分别为:49.28±2.80、85.86±8.55、62.84±2.50、63.76±2.67、62.13±2.28、61.14±2.94、63.16±3.18。芪灯明目胶囊各剂量组、递法明组和导升明组大鼠视网膜PKC蛋白表达低于阴性对照组,差异均有统计学意义(均为P<0.01)。结论芪灯明目胶囊可抑制GK大鼠视网膜PKC蛋白表达,从而抑制新生血管的形成,对糖尿病视网膜组织有一定的保护作用。