Supplementation with branched-chain amino acids attenuates hepatic apoptosis in rats with chronic liver disease

Branched-chain amino acids (BCAA) can function as pharmacologic nutrients for patients with decompensated cirrhosis. However, the effects of BCAA at the early stage of chronic liver disease are not clear. We hypothesized that early BCAA supplementation would attenuate the progression of chronic liver disease. The present study examined the effects of BCAA supplementation on the progression of chronic liver disease in rats caused by injected carbon tetrachloride (CCl₄). Sprague-Dawley rats were fed with a casein diet (control group) or the same diet supplemented with BCAA (BCAA group) for 11 weeks, and all rats were repeatedly injected with CCl₄. Food intake did not significantly differ between control and BCAA groups during the experimental period. Plasma alanine aminotransferase activities gradually increased during the experimental period in both groups but peaked later in the BCAA group. Liver fibrosis was more evident in the control group. Levels of connective tissue growth factor messenger RNA were significantly lower in the livers of rats in the BCAA group than in the control group. Terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end labeling assays found considerably more hepatic apoptosis in the control group. Liver cytosolic cytochrome c levels and expression of the proapoptotic Bax protein in the mitochondrial fraction were significantly lower in the BCAA group than in the control group. These results suggest that supplementation with BCAA delays the progression of chronic liver disease caused by CCl₄ in rats by attenuating hepatic apoptosis.     

COPD患者治疗前后血液细胞因子变化的检测与意义

目的探讨COPD患者治疗前后血液中TNF-α、IL-6、NGF和CTGF等细胞因子的变化。方法分离40例COPD患者常规治疗前后血清,采用放射免疫分析法检测各细胞因子的量,同时选择38名正常健康人做对照。结果 COPD患者治疗后TNF-α、IL-6、NGF和CTGF的量较治疗前有所降低(P<0.05),但COPD患者治疗前后血清中TNF-α、IL-6、NGF和CTGF的量均明显高于正常健康组(P<0.05)。结论 TNF-α、IL-6、NGF和CTGF与COPD疾病的发生有一定的关系,与COPD疾病的严重程度有一定的相关性,各因子含量的变化可用来作为一种判断预后的辅助手段。     

幼年大鼠蛋白尿形成早期肾小管间质CTGF mRNA表达趋势及意义

目的:探讨结缔组织生长因子(CTGF)mRNA在肾病幼鼠蛋白尿形成早期肾组织定位表达趋势及其意义.方法:以蛋白负荷肾病大鼠为实验动物模型,采用原位杂交和免疫组化方法分别检测牛血清的蛋白(BSA)注射后第3、6、9、14 d不同时间点,大鼠肾组织CTGF mRNA和TGF-β1蛋白定位表达趋势及其相关性.结果:蛋白负荷肾病模型组CTGFmRNA主要表达于肾小管间质,从第3 d即趋于上调,于第9 d后即达到高峰(半定量积分值第3、6、9、14d分别为2.50±0.29、2.75±0.13、3.75±0.35、3.77±0.43),各时间点与对照组比有统计学差异(P＜0.05),各时间点模型组间比较有统计学差异(P＜0.05).TGF-β1的蛋白表达与CTGF表达呈同步上调趋势,二者之间在时相、定位上呈正相关,各时间点相关系数分别为(r3=0.767、r6=0.741、r9=0.876、r14=0.793),(P＜0.01).结论:在蛋白尿致肾间质损伤早期,随蛋白尿进行性加重,肾组织中TGF-β1及CTGF的进行高表达可能是促发肾间质病损进展的重要因素.     

病理性瘢痕中结缔组织生长因子的免疫电镜观察

目的：研究结缔组织生长因子（CTGF）在病理性瘢痕组织中的表达定位，以探讨其在病理性瘢痕中的作用及与病理性瘢痕形成的关系。方法：分别留取正常皮肤2例、浅表性瘢痕3例、增生性瘢痕、增生性瘢痕边缘正常皮肤、瘢痕疙瘩及瘢痕疙瘩边缘正常皮肤各5例组织标本，用特异性抗体作为标记物，用胶体金作示踪物进行免疫电镜观察，观察标记物所在位置，以了解在不同组织中表达水平的差异性。结果：CTGF在增生性瘢痕、瘢痕疙瘩、瘢痕疙瘩边缘正常皮肤中的表达均明显高于正常皮肤、浅表性瘢痕及增生性瘢痕边缘正常皮肤。免疫电镜标记显示成纤维细胞细胞超微结构清晰，金颗粒呈团状、点灶状分布，特异性强，CTGF蛋白阳性标记主要位于粗面内质网，粗面内质网核糖体、胶原纤维、细胞外基质、桥粒连接、常染色质等部位也有表达。结论：CTGF与病理性瘢痕的形成有相关性，在其发病过程中可能发挥重要作用。     

TGFβ1，CTGF信号转导通路的变化在实验性小鼠肝纤维发生中的作用

 摘要：目的 探讨实验性肝纤维化小鼠肝组织中TGFβ1,CTGF信号转导通路的变化及意义。方法30只C57BL6/J小鼠随机分为正常对照组、肝纤维化模型组,采用10%的CCL4橄榄油腹腔注射诱导小鼠肝纤维化模型,对照组给予生理盐水灌胃,共造模8周。观察血清ALT、HA水平,HE染色、Masson染色观察肝组织炎症及纤维化程度,免疫组化法和RT-PCR法对肝组织α-SMA、TGFβ1、TGFβRⅡ、Smad3,Smad7,CTGF蛋白和mRNA水平进行检测,并与对照组肝组织进行比较。结果 模型组小鼠血清ALT及HA水平明显高于对照组;模型组小鼠肝组织α-SMA、TGFβ1、TGFβRII、Smad3、CTGF蛋白表达和TGFβ1、Smad3、CTGF mRNA表达明显高于对照组,而模型组肝组织Smad7蛋白和Smad7 mRNA表达较对照组小鼠显著降低。结论 TGFβ1和CTGF信号转导通路过度活化,Smad7表达和负调节TGFβ、CTGF信号转导通路的功能被抑制可能与肝纤维化的发生和发展密切相关。     

乙肝后肝硬化患者血清CTGF、PDGF、TGF-β_1测定的意义

目的：探讨乙型肝炎后肝硬化患者血清CTGF、PDGF、TGF-β1水平的变化及临床意义。方法：将50例乙肝后肝硬化患者按不同的病情分为轻度、中度及重度三组;设体检健康人45名作为对照组。血清TGF-β1水平采用放射免疫分析;CTGF及PDGF则采用ELISA测定。并将测定结果进行统计分析。结果：结果显示,血清CTGF水平轻度组与对照组比较略有升高,但无统计学意义（P〉0.05）;中度组患者该指标水平则显著高于对照组（P〈0.05）;重度组水平更为显著（P〈0.01）。且发现其递增规律与肝硬化病情的严重程度呈明显的平行关系。PDGF测定值显示,轻度组水平显著高于对照组（P〈0.05）,中度和重度两组水平则较对照组升高更为显著（P均〈0.01）。其水平的递增关系也与病情的严重程度相一致。TGF-β1水平的变化趋势同PDGF。结论：本文患者三项血清指标水平的变化与乙肝后肝硬化的发病及病情进展有关;其测定有助于了解本病的发生机制和预后评估。     

Targeting podocyte-associated diseases

Injury to the podocytes is the initiating cause of many renal diseases, leading to proteinuria with possible progression to end-stage renal disease. Podocytes are highly specialized cells, with an important role in maintaining the glomerular filtration barrier and producing growth factors for both mesangial cells and endothelial cells. With their foot processes they cover the glomerular basement membrane, and form slit diaphragms with neighboring podocytes.Human podocytopathies include focal and segmental glomerulosclerosis, minimal change disease, membranous nephropathy, collapsing glomerulopathy and diabetic nephropathy. Research in the last two decades has demonstrated great progress in understanding the molecular mechanisms leading to podocytopathies. These include single gene defects in slit diaphragm proteins, but also discovery of apoptotic, enzymatic and other pathways involved in podocyte injury. With this progress, a great number of animal models is now available to study either specific podocytopathies, e.g. in mouse models with single gene mutations, or more general podocyte injury patterns, such as the lipopolysaccharide or protamine sulfate model of foot process effacement.In this review, the morphology of the glomerulus will be discussed, with a focus on the podocyte, its interactions with surrounding cells, and the highly differentiated slit diaphragm separating the apical from the basal membrane. We also provide an overview of human podocytopathies and animal models to study these diseases. In the last part we discuss targeted therapies addressing pathways and proteins affected in podocyte injury.     

海参虫草复剂对糖尿病大鼠肾脏保护作用机制的研究

目的研究海参虫草复剂(AC)对链脲佐菌素(Streptozocin,STZ)诱导的糖尿病大鼠肾脏保护作用机制。方法采用一次性腹腔注射STZ的方法建立糖尿病大鼠模型,经过长期高血糖环境下饲养造成肾脏损伤。灌胃AC8周后,分别检测大鼠空腹血糖、肾脏指数、24h尿微量白蛋白排泄率(UAER)及肾脏的氧化应激水平;采用RT-PCR法测定肾脏中转化生长因子β1(TGF-β1)及其Ⅱ型受体(TβRⅡ)、结缔组织生长因子(CTGF)mRNA表达。Western blot方法检测肾脏中TGF-β1蛋白表达,免疫组化法检测肾脏中Ⅳ型胶原蛋白表达。结果 AC能降低糖尿病大鼠空腹血糖、肾脏指数和UAER(P<0.05,P<0.01),提高肾脏抗氧化能力,下调TGF-β1、TGFβRⅡ和CTGF的mRNA表达(P<0.05,P<0.01),降低TGF-β1及Ⅳ型胶原的蛋白表达水平(P<0.01)。结论 AC可通过改善糖尿病大鼠肾脏氧化应激状态,抑制TGF-β1、TβRⅡ和CTGF基因表达,以减少尿蛋白排泄及阻止肾脏肥大,从而达到保护肾脏的作用。     

胰岛素样生长因子1对大鼠肾间质纤维化组织中CTGF的表达影响

目的观察胰岛素样生长因子1（IGF-1）对肾间质纤维化大鼠结缔组织生长因子（CTGF）表达的影响。方法 30只Wistar大鼠随机分为假手术组、模型组、IGF-1组,每组10只。应用单侧输尿管结扎制备肾间质纤大鼠模型。假手术组打开腹腔后即缝合;模型组每日腹腔注射生理盐水0.5ml;IGF-1组腹腔注射重组人IGF-1 750ng.kg-1.d-1。术后第14d麻醉大鼠后取材,检测肾功能,观察Ⅳ型胶原蛋白、结缔组织生长因子（CTGF）的表达。结果模型组血肌酐、尿素氮、Ⅳ型胶原蛋白、CTGF的表达水平均高于假手术组,差异有统计学意义（P〈0.05）;IGF-1干预后,IGF-1组血尿素氮、血肌酐、Ⅳ型胶原蛋白、CTGF的表达水平均高于假手术组及模型组,差异有统计学意义（P〈0.05）。结论 IGF-1参与梗阻性肾病的病理生理过程,尤其在肾间质纤维增生过程中起着重要作用。     

不对称咀嚼力作用下CTGF在髁突软骨中的表达

目的探讨不对称咀嚼肌力对SD大鼠髁突软骨改建的影响.方法通过手术切除一侧颞肌和肉毒神经毒素A注射一侧咬肌,建立不对称咀嚼肌力SD大鼠动物模型,每组6只,分别于建模后3、6、9周处死动物,免疫组织化学检测CTGF在大鼠髁突软骨中的表达.结果 CTGF在髁突软骨增殖层、成软骨细胞层和肥大层表达;实验组CTGF的表达均较空白对照组增强(P<0.05);实验组双侧髁突CTGF表达无明显差异(P>0.05);实验组术后6周CTGF表达强于术后3周,术后9周强于术后6周(P<0.05).结论不对称咀嚼肌力可上调髁突软骨细胞CTGFmRNA的表达,CTGF介导了应力对髁突软骨的改建.