Vit E对动脉粥样硬化模型兔动脉肌球蛋白轻链激酶表达的影响

目的　研究动脉粥样硬化 (AS)模型兔动脉肌球蛋白轻链激酶表达的变化以及VitE对MLCK表达的影响。方法　复制AS兔模型 ;颈动脉取血后检测血清标本中各种血脂成分的变化 ,用免疫组化法和Westernblot分析动脉粥样硬化模型兔动脉MLCK的表达。结果　成功建立AS兔模型 ,模型血清中各种脂质发生显著变化。免疫组化和West ernblot实验表明 ,动脉粥样硬化模型兔在喂食胆固醇膳食 4wk和 12wk后动脉MLCK的表达增强 ,在喂食胆固醇膳食12wk同时添加VitE时 ,MLCK表达降低。结论　AS模型兔动脉MLCK的表达增强与动脉粥样硬化的形成相关。VitE可能是降低动脉MLCK表达的因素 ,同时抑制动脉粥样硬化的形成。     

VitE对动脉粥样硬化模型兔肝脏肌球蛋白轻链激酶活性及表达的影响

目的　探讨维生素E(VitE)对动脉粥样硬化模型兔肝脏MLCK活性及表达的影响。方法　复制兔动脉粥样硬化模型 ,用γ 3 2 P参入法检测肝脏MLCK活性 ,免疫荧光法检测肝组织MLCK的表达。结果　动脉粥样硬化兔模型建立成功 ,在喂胆固醇 4wk及 12wk的动物组 ,肝脏MLCK活性[分别为 (1884 8 7± 74 34 3)、(18818 3± 346 9 9)cpm·mg-1protein]与正常对照比较 [(6 6 77 5± 10 9 6 0 )cpm·mg-1pro tein]升高 (P <0 0 5 ) ;但在喂胆固醇同时添加VitE后 ,肝脏MLCK活性 [(10 898 8± 2 0 4 1 2 )cpm·mg-1protein]与正常对照组比较升高不明显 (P >0 0 5 )。荧光显微镜下观察显示 ,兔肝在喂食胆固醇膳食 4wk后MLCK的表达有所增强 ,12wk后显著增强 ,12wk组的膳食中同时加VitE后 ,MLCK表达有所下降。结论　在动脉粥样硬化过程中 ,肝脏病变可能与MLCK活性增强有关 ,VitE可能是降低肝脏MLCK活性的因素 ,同时防止肝细胞的损伤     

胰岛素对糖尿病模型大鼠肾脏肌球蛋白轻链激酶表达的影响

已知糖尿病早期肾小球滤过率(GFR)升高,并与糖尿病肾病的发展有关[1,2].肾小动脉血管平滑肌的收缩改变了肾血流动力学是引起GFR升高的原因之一.探索糖尿病肾血管平滑肌收缩的调控因素可为进一步阐明糖尿病发生发展机制打下良好的基础.肌球蛋白轻链激酶(MLCK)表达增加和活性升高是血管平滑肌收缩的启动因素之一[3].糖尿病个体是否存在MLCK表达的变化尚未见报道.本研究在复制大鼠糖尿病模型的基础上,观察胰岛素对糖尿病大鼠肾MLCK表达的影响.     

白藜芦醇下调肌球蛋白轻链激酶过表达抑制大鼠肝肿瘤增生

目的研究白藜芦醇(Res)通过影响肌球蛋白轻链激酶(MLCK)在肝脏中表达水平抑制原发性肝癌的增生。方法采用口服饮水中含0.9 mmol.L-1二乙基亚硝胺10周诱发原发性肝肿瘤;20周后,治疗组大鼠每天给予肌肉注射Res 50 mg.kg-16周;26周后,处死大鼠,计数肝表面癌结节数,称量和计算体重、肝重,肝/体重比,测定血清中甲胎蛋白的变化,观察大鼠肝脏的病理改变;用免疫组化和Westernblot法检测Res对MLCK的表达影响,用细胞凋亡试剂盒检测Res诱导肿瘤细胞的凋亡。结果 Res治疗组大鼠和模型组大鼠相比,体重增加,肝肿瘤结节数和肝/体重比和血清甲胎蛋白值减少或降低(P<0.05)。模型组大鼠肝组织MLCK的表达水平明显增加,而Res治疗可逆转MLCK的过表达水平,并诱导肿瘤细胞凋亡。结论 Res通过下调肝组织MLCK的表达水平诱导凋亡,抑制大鼠肝肿瘤细胞的增生。     

芍药苷抑制肌球蛋白轻链激酶缓解肠上皮细胞屏障功能紊乱

目的考察芍药苷对肿瘤坏死因子α(TNF-α)所致Caco-2模拟的肠上皮细胞屏障功能紊乱的保护作用及相关机制。方法体外培养Caco-2细胞,采用MTT法研究芍药苷对Caco-2细胞活性的影响;建立TNF-α所致Caco-2细胞的屏障功能紊乱模型,研究芍药苷对屏障功能的影响。结果TNF-α孵育Caco-2细胞,明显降低了Caco-2细胞屏障的跨膜电阻,肌球蛋白轻链激酶(MLCK)表达明显增加,紧密连接蛋白occludin和ZO-1表达明显下降,提示Caco-2细胞屏障功能紊乱;芍药苷明显逆转TNF-α所造成的Caco-2细胞屏障功能紊乱,即抑制MLCK的表达,促进紧密连接蛋白occludin和ZO-1的表达,芍药苷的这种保护细胞屏障的作用可被MLCK的小分子干扰RNA(small interfering RNA,siRNA)所阻断。结论芍药苷可明显缓解TNF-α诱导的肠上皮屏障功能紊乱,该作用与降低MLCK,促进紧密连接蛋白表达有关。     

环状 RNA肌球蛋白轻链激酶靶向微小 RNA-497-5p调控结肠癌细胞的增殖、迁移和侵袭

目的探讨环状 RNA肌球蛋白轻链激酶( circMYLK)对结肠癌细胞增殖、迁移和侵袭的影响和可能机制。方法本研究 2019年 3月至 2020年 1月进行。实时荧光定量 PCR(RT-qPCR)检测检测正常结肠上皮细胞( NCM460)和结肠癌细胞(SW480、SW620、Caco-2)中 circMYLK和微小 RNA-497-5p(miR-497-5p)表达水平。将 circMYLK小干扰 RNA(si-circMYLK)、 miR-497-5p模拟物分别转染 SW480细胞,采用细胞计数试剂盒(CCK-8)、 Transwell实验分别检测干扰 circMYLK或过表达 miR-497-5p对 SW480细胞增殖、迁移和侵袭的影响。双荧光素酶报告基因实验和 RT-qPCR确定 circMYLK对 miR-497-5p的调控作用。结果与 NCM460细胞比较,结肠癌细胞中 circMYLK表达( 1.00±0.06比 3.39±0.23、2.31±0.24、2.98±0.18)显著升高, miR-497-5p表达( 1.00±0.08比 0.36±0.04、0.63±0.05、0.54±0.05)显著降低( P<0.05)。干扰 circMYLK表达后 SW480、细胞活力、迁移和侵袭细胞数显著降低( P<0.05)。过表达 miR-497-5p后 SW480细胞活力、迁移和侵袭细胞数显著降低( P<0.05)。 circMYLK靶向负性调控 miR-497-5p表达。抑制 miR-497-5p表达能够逆转干扰 circMYLK对 SW480细胞增殖、迁移和侵袭的影响,恢复细胞活力、迁移和侵袭能力( P<0.05)。结论结肠癌细胞中 circMYLK呈高表达,干扰 circMYLK通过靶向 miR-497-5p能够抑制结肠癌细胞增殖、迁移和侵袭。     

地塞米松对哮喘动物模型支气管平滑肌MLCK表达的影响

目的观察地塞米松(DXM)对哮喘动物模型支气管平滑肌肌球蛋白轻链激酶(MLCK)表达的影响,探讨MLCK在哮喘发病中的作用。方法24只♂SD大鼠,随机等分为正常对照组、哮喘模型组和地塞米松组。以卵蛋白(OVA)诱发大鼠支气管哮喘模型。地塞米松组大鼠于每次激发前1h给予腹腔注射地塞米松0.5mg·kg-1。用免疫组织化学法和免疫印迹法分析三组大鼠支气管平滑肌中MLCK表达。结果免疫组织化学法分析显示DXM组大鼠支气管平滑肌MLCK的表达低于哮喘模型组(P<0.05),但与正常对照组比较差异无显著性(P>0.05)。同时,免疫印迹法检测也表明哮喘模型组大鼠smMLCK表达高于正常对照组及地塞米松组。结论MLCK参与支气管哮喘的发病,地塞米松通过下调哮喘大鼠支气管平滑肌MLCK表达,可能是糖皮质激素治疗哮喘的一种机制。     

螺旋藻激酶对动脉粥样硬化模型大鼠血管内皮功能的影响

目的:研究螺旋藻激酶(SPK)对动脉粥样硬化模型大鼠血管内皮功能的影响。方法:将60只大鼠随机分为正常对照组(蒸馏水)、模型组(蒸馏水)、阳性对照组(辛伐他汀,0.005 g/kg)和SPK低、中、高剂量组(80、160、320 U/kg)。除正常对照组外,其余各组大鼠均复制动脉粥样硬化模型;同时,各组大鼠ig相应药物,每天1次,连续给药12周。测定大鼠血清中总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)的含量;苏木精-伊红染色观察大鼠胸主动脉血管内膜的形态改变。结果:与正常对照组比较,模型组大鼠血清中TC、TG、LDL-C、IL-6和TNF-α含量增加(P<0.01),HDL-C含量降低(P<0.01);血管内皮细胞脱落,内膜增生、向管腔内突起,平滑肌细胞增殖且排列紊乱,中膜弹力纤维崩解断裂。与模型组比较,各给药组大鼠血清中TC、TG、LDL-C、IL-6和TNF-α含量下降(P<0.05或P<0.01),阳性对照组和SPK中、高剂量组大鼠血清中HDL-C含量增加(P<0.05);给药组大鼠血管内皮细胞形态较模型组明显改善,其中SPK中、高剂量组大鼠血管内皮细胞各层结构完整、内膜基本光滑,SPK中剂量组大鼠血管中膜平滑肌细胞排列稍紊乱,与正常对照组比较无明显变化。结论:SPK有明显的降脂和抗炎作用,可保护血管内皮功能;其作用机制可能与降低血清中TC、TG、LDL-C、IL-6、TNF-α含量和升高血清中HDL-C含量有关。     

巴曲酶对兔动脉粥样硬化模型的影响

目的：探讨巴曲酶对动脉粥样硬化的影响及机理。方法：将日本大耳白兔分成对照组和高脂组，待高脂组形成动脉粥样硬化模型后分为3组（安慰剂组、治疗1组和治疗2组）。治疗组以巴曲酶干预4周，同时安慰剂组和对照组注射生理盐水，进行病理观察并对血脂及纤维蛋白原进行分析。结果：治疗4周后治疗组兔动脉粥样硬化斑块趋于稳定，血脂及纤维蛋白原降低（P＜0．05）。结论：巴曲酶具有稳定动脉粥样硬化斑块的作用，其机理可能是巴曲酶能降低血纤维蛋白原、平衡脂质分布。     

朱日很滴丸对动脉粥样硬化模型兔MMP-9表达量的影响

目的研究朱日很滴丸对动脉粥样硬化模型兔基质金属蛋白酶9(MMP-9)表达量的影响。方法 1.采用高脂饲料+牛血清白蛋白(250 mg·kg^-1)对日本大耳白兔进行造模,第8周造模成功后,朱日很滴丸低、中和高剂量组分别灌胃朱日很滴丸溶液116,367和1 160 mg·kg^-1,普罗布考组灌胃普罗布考溶液26 mg·kg^-1,每日1次,连续4周。实验期间,溶媒对照组给予普通饲料,其余组结予高脂饲料。实验结束后采集各组兔血清及主动脉,通过Elisa法和免疫组化法(IHC-P)测定朱日很滴丸对动脉粥样硬化模型兔血清和主动脉MMP-9表达量的影响;2.将氧化性低密度脂蛋白(ox-LDL)与人脐静脉内皮细胞(HUVEC)共同孵育,建立内皮细胞损伤模型,加入朱日很滴丸含药血清进行干预。通过实时荧光定量PCR法(qPCR)和蛋白免疫印迹法(Western Blot)检测朱日很滴丸含药血清对内皮细胞氧化损伤模型中MMP-9的mRNA水平和蛋白含量的影响。结果与模型组相比,朱日很滴丸低、中和高剂量组兔血清与主动脉斑块中MMP-9表达量均显...     

Combined subthreshold dose inhibition of myosin light chain phosphorylation and MMP-2 activity provides cardioprotection from ischaemic/reperfusion injury in isolated rat heart

BACKGROUND AND PURPOSE

Phosphorylation and degradation of myosin light chain 1 (MLC1) during myocardial ischaemia/reperfusion (I/R) injury is a well-established phenomenon. It has been established that MMP-2 is involved in MLC1 degradation and that this degradation is increased when MLC1 is phosphorylated. We hypothesized that simultaneous inhibition of MLC1 phosphorylation and MMP-2 activity will protect hearts from I/R injury. As phosphorylation of MLC1 and MMP-2 activity is important for normal heart function, we used a cocktail consisting combination of low (subthreshold for any protective effect alone) doses of MLC kinase, MMP-2 inhibitors and subthreshold dose of an MLC phosphatase activator.

EXPERIMENTAL APPROACH

Isolated rat hearts were subjected to 20 min of global, no-flow ischaemia and 30 min reperfusion in the absence and presence of inhibitors of MLC1 phosphorylation and degradation.

KEY RESULTS

The recovery of cardiac function was improved in a concentration-dependent manner by the MLC kinase inhibitor, ML-7 (1–5 μM), the MLC phosphatase activator, Y-27632 (0.05–1 μM) or the MMP inhibitor, doxycycline (Doxy, 1–30 μM). Co-administration of subthreshold doses of ML-7 (1 μM) and Y-27632 (0.05 μM) showed a potential synergistic effect in protecting cardiac contractility and MLC1 levels in I/R hearts. Further combination with a subthreshold concentration of Doxy (1 μM) showed additional protection that resulted in full recovery to control levels.

CONCLUSIONS AND IMPLICATIONS

The results of this study exemplify a novel low-dose multidrug approach to pharmacological prevention of reperfusion injury that will enable a reduction of unwanted side effects and/or cytotoxicity associated with currently available MMP-2 and kinase inhibiting drugs.     

Inhibition of turkey gizzard myosin light chain. Kinase activity by dihydropyridine calcium antagonists

Drugs which block the influx of calcium (Ca2+) across plasma membranes may additionally have direct effects upon smooth muscle contractile proteins. In a system of purified proteins comprised of calmodulin, turkey gizzard myosin light chains, and turkey gizzard myosin light chain kinase, the inhibition of myosin light chain phosphorylation by the dihydropyridine Ca2+ antagonists felodipine [3-ethyl-5-methyl-1-1,4-dihydro-2,6-dimethyl-4-(2,3-dichlorophenyl)-3, 5-pyridine dicarboxylate] and nitrendipine [3-ethyl-5-methyl-1-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridine dicarboxylate] was studied. In the presence of excess myosin light chain kinase, 50% inhibition of myosin light chain phosphorylation occurred at felodipine and nitrendipine concentrations of 9.8 +/- 1.1 X 10(-6) M and 5.6 +/- 0.6 X 10(-5) M respectively. Inhibition of light chain kinase activity could not be overcome by increasing the free Ca2+ concentration from 0.05 to 5.0 mM. Felodipine was unable to inhibit the activity of myosin light chain kinase rendered Ca2+/calmodulin-independent by limited tryptic digestion. Using molecular sieve chromatography, nitrendipine was found to bind to calmodulin with an apparent dissociation constant (Kapp) of 5.2 +/- 0.3 X 10(-5) M, and this binding was Ca2+ dependent. These data suggest that dihydropyridines inhibit the phosphorylation of smooth muscle myosin light chains in vitro by binding to Ca2+/calmodulin and inhibiting the activation of myosin light chain kinase.     

力平脂对兔粥样硬化血管壁组织内内皮素-1和一氧化氮合酶mRNA表达的影响(英文)

目的:探讨力平脂消退动脉粥样硬化的作用机制民。方法:给兔喂饲高脂饲料8周,加腹主动脉内皮损伤造成腹主动脉粥样硬化模型,然后用力平脂15mg·kg~(-1)·d~(-1)治疗16周。粥样硬化血管壁组织中内皮素(ET)-1和一氧化氮合酶(NOS)mRNA的表达分别采用原位杂交和逆转录多聚酶链反应(RT-PCR)测定。结果:力平脂治疗16周后,ET-1 mRNA表达明显减少,其阳性杂交颗粒的积分光密度(IOD)和面积分别由粥样硬化组的(65188±10113)和(3028±352)μm~2下降至(49113±16868)和(2448±621)μm~2。力平脂也可降低诱导型NOS mRNA的表达,使IOD和面积分别下降25.5％和53.3％,但通过RT-PCR测得的内皮型NOS mRNA表达增加。结论:恢复ET-1 mRNA/NOS mRNA的平衡可能是力平脂消退动脉粥样硬化的机制之一。     

The effect of clonidine and bright light on plasma melatonin

We studied the effect of the α₂-adrenoceptor agonist, clonidine, and bright artificial light (>2500 lux) on the nocturnal increase in plasma melatonin in normal subjects. Clonidine (1.5 μg/kg, intravenously) was without effect on plasma melatonin concentration. In contrast, bright light treatment abolished the increase in night-time melatonin. Bright light is a simple and effective means of altering melatonin secretion in humans.     

Myosin light chain kinase is responsible for high proliferative ability of breast cancer cells via antiapoptosis involving p38 pathway

Aim:

To investigate whether myosin light chain kinase (MLCK) contributed to the high proliferative ability of breast cancer cells.

Methods:

Soft agar colony formation on the MCF-7 and LM-MCF-7 cell lines was determined. The cell cycles of MCF-7 and LM-MCF-7 were detected using flow cytometry analysis. Western blot analysis was performed to detect the expression levels of p-ERK1/2, total-ERK1/2, p-p38, total p38, p-JNK, total-JNK, survivin, Bcl-2, p-MLC, caspase-9, cleaved caspase-9, and MLCK. After treatment with adriamycin (ADR), ML-7 and SB203580, apoptosis was examined using flow cytometry analysis and Annexin V-FITC fluorescence microscopy.

Results:

The breast cancer LM-MCF-7 cell line with high metastasis potential (a metastitic sub-clone of MCF-7) had higher anti-apoptosis ability relative to MCF-7 cells in response to adriamycin treatment (apoptosis rate: 6.76% vs 28.58%, P<0.05). Moreover, the expression level of MLCK was upregulated and the level of phosphorylated p38 (p-p38) was decreased in LM-MCF-7 cells. Flow cytometry analysis showed that ML-7, selective inhibitor of MLCK, could induce apoptosis of the LM-MCF-7 cells, in which the level of p-p38 was increased. Meanwhile, the expression levels of Bcl-2 and survivin were downregulated, while the caspase-9 was upregulated suggesting that the cells were undergone apoptosis. Flow cytometry analysis showed that SB203580, an inhibitor of p38, abolished ML-7-induced apoptosis, which resulted in the upregualtion of Bcl-2 and survivin, and downregulation of caspase-9, suggesting that Bcl-2, survivin and caspase-9 are downstream effectors of p38.

Conclusion:

MLCK is responsible for high proliferative ability of breast cancer cells through anti-apoptosis, in which p38 pathway was involved.     

番茄红素对动脉粥样硬化家兔血脂及低密度脂蛋白受体mRNA表达的影响

目的:通过建立家兔动脉粥样硬化模型,观察低密度脂蛋白受体(LDLR)mRNA在实验性动脉粥样硬化家兔主动脉平滑肌细胞和心肌细胞的表达及番茄红素对其表达的影响。方法:采用高脂饲料建立家兔动脉粥样硬化模型,造模60d,从第61d起给予番茄红素进行干预,连续用药40d后,测定血清脂质总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)]含量,采用RT-PCR法检测LDLR在主动脉平滑肌细胞和心肌细胞mRNA的表达。所有数据经SPSS13.0软件进行统计分析。结果:番茄红素大剂量组家兔血清TG含量明显低于模型组(P<0.05),而番茄红素小剂量组与模型组比较差异无显著性。RT-PCR结果表明番茄红素能够抑制家兔主动脉和心脏LDLR mRNA的表达。结论:番茄红素对动脉粥样硬化家兔的血脂和脂蛋白代谢紊乱具有调节作用,其作用机制可能与降低TG浓度、抑制LDLR的表达有关。