Lipoic acid prevents collagen abnormalities in tail tendon of high-fructose-fed rats

BACKGROUND: Non-enzymatic glycation of proteins, leading to chemical modification and cross-linking are of importance in the pathology of diabetic complications. We studied the effect of alpha-lipoic acid (LA) on the glycation and cross-linking of collagen from tail tendon of high-fructose-fed rats. METHODS: The rats were divided into four groups of six each. Two groups of rats were fed with a high-fructose diet (60/100 g diet) and administered with either LA (35 mg/kg body weight, intraperitoneally) (FRU + LA) or saline (FRU) for 45 days. The other two groups were fed control diet containing starch (60/100 g diet) and administered with either saline (CON) or LA (CON + LA). The rats were maintained for 45 days and then sacrificed. Collagen was isolated from tail tendon and the extent of glycation, fluorescence, aldehyde and peroxidation levels were measured. The tail tendons were separated, and shrinkage temperature was also measured. Acid-soluble collagen was extracted from tail tendon and subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis. RESULTS: Fructose administration caused accumulation of collagen in tail tendon. Glycation, collagen-linked fluorescence, aldehyde and peroxide contents were elevated. The gel pattern of acid-soluble collagen from the fructose-fed rat showed elevated beta-component. These changes were alleviated by the simultaneous administration of LA. CONCLUSION: Administration of LA has a positive influence on tail tendon collagen glycation and other variables in high-fructose-fed rats.     

Fructose diet-induced skin collagen abnormalities are prevented by lipoic acid

Nonenzymatic glycation of proteins, leading to chemical modification and cross-linking are of importance in the pathology of diabetic complications. We studied the effect alpha-lipoic acid (LA) on the content and characteristics of the protein collagen from skin of high-fructose fed rats. The rats were divided into 4 groups of 6 each. Two groups of rats were fed with a high fructose diet (60 g/100 g diet) and administered either LA (35 mg/kg b.w., i.p) (FRU+LA) or 0.2 ml vehicle (saline) (FRU) for 45 days. The other 2 groups were fed with control diet containing starch (60 g/100 g diet) and administered either saline (CON) or lipoic acid (CON+LA). The rats were maintained for 45 days and then sacrificed. Plasma glucose, insulin, fructosamine, protein glycation, and blood glycated hemoglobin (HbA1C) were measured. Collagen was isolated from skin and the physicochemical properties of collagen were studied. Fructose administration caused accumulation of collagen in skin. Extensive cross-linking was evidenced by enhanced glycation and AGE-linked fluorescence. Increased peroxidation and changes in physicochemical properties such as shrinkage temperature, aldehyde content, solubililty pattern, susceptibility to denaturing agents were observed in fructose-fed rats. SDS gel pattern of collagen from these rats showed elevated beta component of type I collagen. These changes were alleviated by the simultaneous administration of LA. Administration of LA to fructose-fed rats had a positive influence on both quantitative and qualitative properties of collagen. The results suggest a mechanism for the ability of LA to delay diabetic complications.     

Taurine prevents myocardial ischemia/reperfusion-induced oxidative stress and apoptosis in prolonged hypothermic rat heart preservation

Taurine (2-aminoethanesulfonic acid) is a potent antioxidant and inhibits cell apoptosis in ischemic reperfusion injury. In this study we evaluated whether addition of taurine to St. Thomas' cardioplegic solution enhances its myocardial protective effects in prolonged hypothermic heart preservation in rats. Hearts isolated from male Sprague–Dawley rats were mounted on a Langendorff apparatus to estimate baseline cardiac function, then arrested and stored in St. Thomas' cardioplegic solution, with taurine (10 mM; taurine group, n = 8) or without taurine (control group, n = 8), for 6 h at 4°C. After storage, the hearts were reperfused and heart rate (HR), coronary flow (CF), left ventricular developed pressure (LVP), and positive maximum left ventricular developing pressure (max LV dp/dt) were measured. The LV tissue was examined immunohistochemically for determining DNA oxidative stress and cell apoptosis. Compared with control groups, recovery of LVP (P < 0.001), max LV dp/dt (P < 0.001), and coronary flow (P < 0.001) were significantly enhanced, whereas glutamic oxaloacetic transaminase (P < 0.01), lactate dehydrogenase (P < 0.05), creatine phosphate kinase (P < 0.01), 8-hydroxy-2′-deoxyguanosine index (P < 0.01), caspase-3 mRNA expression (P < 0.05), and percentage of TUNEL-positive cardiomyocytes (P < 0.05) were reduced in the taurine group. Addition of taurine to St. Thomas' cardioplegic solution improved cardiac function recovery for prolonged hypothermic rat heart preservation by suppressing DNA oxidative stress and cell apoptosis.     

雷公藤甲素诱导胶原诱导的关节炎大鼠滑膜细胞凋亡的初步观察

目的 以胶原诱导的关节炎(CIA)为动物模型,探讨雷公藤甲素(triptolide)能否诱导CIA大鼠滑膜细胞凋亡。方法 选用雄性Wistar大鼠造模,将造模成功的大鼠随机分为模型组和雷公藤组。雷公藤甲素按4滋g/100g体重,肌肉注射给药,每3d1次。凋亡检测:给药31d后处死,取膝关节滑膜。作苏木素-伊红染色(HE)、电镜、缺口末端标记法(TUNEL)标记及流式细胞仪检测。结果 电镜下可见早期阶段的滑膜凋亡细胞。流式细胞仪检测结果显示正常组、模型组、雷公藤组的凋亡细胞分别为(0.87±0.24)%、(1.83±0.82)%和(3.98±1.16)%。正常组、模型组、雷公藤组的S期细胞分别为(3.4±0.7)%、(8.0±1.4)%和(3.3±1.2)%。雷公藤组与模型组比较差异均具有显著性(P<0.01)。TUNEL标记结果显示正常组、模型组、雷公藤组的凋亡细胞分别为(1.0±0.4)%、(2.2±1.0)%和(4.5±0.9)%。雷公藤组与模型组比较差异具有显著性(P<0.01)。结论 本次实验首次阐明雷公藤甲素可诱导CIA大鼠滑膜细胞的凋亡。     

Taurine administration prevents the intestine from the damage induced by beta-lactoglobulin sensitization in a murine model of food allergy

Background

Allergy to cow's milk proteins has often been associated with dysfunction of the intestinal mucosa caused by chronic inflammation in infants. This study evaluated the protective effect of taurine on intestinal damage induced by beta-lactoglobulin (β-Lg) in Balb/c mice used as an animal model of allergy to cow's milk proteins.

Gastrointestinal abnormalities in the collagen diseases

Summary Gastrointestinal manifestations of the collagen diseases (systemic lupus erythematosus, polyarteritis, progressive systemic sclerosis, and dermatomyositis) have been presented as demonstrated in 61 patients. These manifestations indicate in terms of the clinical, radiologic, and pathologic findings, extensive gastrointestinal damage by a severe progressive process.     

Tensile properties of rat anterior cruciate ligament in collagen induced arthritis

OBJECTIVES: To investigate the effects of collagen induced arthritis (CIA) on the tensile properties of rat anterior cruciate ligament (ACL). METHODS: The tensile strength, bone mineral density (BMD), and histology of ACL units from rats with CIA were investigated. RESULTS: The tensile strength of the ACL unit was significantly lower in the rats with CIA at 10 weeks after immunisation (ultimate failure load, 74.9% of the control; stiffness, 62.0% of the control). The major mode of failure was femoral avulsion, and the BMD was significantly lower in the rats with CIA. A histological examination of the ligament insertion in rats with CIA showed resorption of the cortical bone beneath the ACL insertion and an enlarged mineralised fibrocartilage zone. CONCLUSIONS: These findings indicate that the decrease in tensile strength of ACL units correlated with histological changes in the ligament-bone attachment, such as bone resorption beneath the ligament insertion site and an enlargement of the mineralised fibrocartilage zone.     

Taurine inhibits oxidative damage and prevents fibrosis in carbon tetrachloride-induced hepatic fibrosis

BACKGROUND/AIMS: The aim of the study was to examine the effects of taurine on hepatic fibrogenesis and in isolated hepatic stellate cells (HSC). METHODS: The rats of the hepatic damage (HD) group were administered carbon tetracholoride (CCl4) for 5 weeks and a subgroup received, in addition, a 2% taurine containing diet for 6 weeks (HDT). The HSC were isolated from normal rats and cultured for 4 days. RESULTS: The hepatic taurine concentration was decreased in the HD group. This loss and the hepatic histological damage and fibrosis (particularly in the pericentral region), were reduced following taurine treatment. Furthermore, the hepatic alpha-SMA, lipid hydroperoxide and 8-OHdG levels in serum and liver, as well as hepatic TGF-beta1 mRNA and hydroxyproline levels were significantly increased in the HD group, and most of these parameters were significantly reduced following taurine treatment. In contrast to the MAP-kinase and Akt expressions, which remained unchanged, the lipid hydroperoxide and hydroxyproline concentrations, as well as TGF-beta1 mRNA levels were significantly reduced by taurine in activated HSC. CONCLUSIONS: Oral taurine administration enhances hepatic taurine accumulation, reduces oxidative stress and prevents progression of hepatic fibrosis in CCl4-induced HD rats, as well as inhibits transformation of the HSC.     

Ketotifen prevents skin fibrosis in the tight skin mouse

Mast cells in the skin of the tight-skin mouse show an enhanced degranulation compared to those of syngeneic litter mates. Oral treatment with ketotifen, an inhibitor of mast cell degranulation, at a dose comparable to that recommended for man, was associated with a decrease in both mast cell degranulation and in skin fibrosis, suggesting the potential for its use in human scleroderma.     

Imatinib mesylate both prevents and treats the arthritis induced by type II collagen antibody in mice

Rheumatoid arthritis (RA) is a chronic inflammatory disease that is associated with joint destruction. Imatinib mesylate (imatinib) is an inhibitor that specifically targets a set of protein tyrosine kinase, such as abl, c-kit, and platelet-derived growth factor receptor (PDGFR) and it is widely used to treat chronic myeloid leukemia (CML). The purpose of the present study is to determine whether imatinib can provide benefit in the arthritis induced by anti-collagen type II antibody (CAIA) in mice, a model that provides an opportunity to study the effector inflammatory phase of arthritis without involving the priming phase of the immune responses. Mice treated with intraperitoneal administration of imatinib (1 or 10 mg/kg) prior to the development of CAIA displayed significant reductions in the severity of CAIA as assessed by arthritis score, histology, and synovial PDGF and vascular endothelial growth factor expression. In addition, treatment of the mice that had developed CAIA with intraperitoneal administration of imatinib (1 or 10 mg/kg) inhibited the progression of arthritis as assessed by those parameters. These results suggest that imatinib prevents and treats CAIA. Imatinib may thus have both a preventive and therapeutic potential for the joint inflammation at the effector stage of RA.     

Mallory body-like abnormalities in carcinomas induced by cultured transformed rat liver cells

Hepatoma cells isolated from rats after administration of a carcinogen, diethylnitrosamine, and propagated in culture, contained a genetically stable cytoskeletal abnormality resembling Mallory bodies. These juxtanuclear aggregates of intermediate-sized filaments were maintained in carcinomas produced in nude mice after inoculation of uncloned mass cultures and a cloned subculture. Paraffin and frozen sections of these tumors revealed acentric nuclei and a glassy hyalin-type cytoplasmic lesion which stained pink with hematoxylin-eosin and blue with Mallory's aniline blue stain. The cells in culture and in the tumor sections were strongly positive for gamma-glutamyl transpeptidase. Cryostat sections examined by indirect immunofluorescence microscopy with antisera to purified bovine hoof prekeratin, desmosome-associated tonofilaments from bovine muzzle, and murine vimentin, as well as transmission electron microscopy revealed the presence of juxtanuclear aggregates of intermediate-sized filaments. All characteristics previously reported for the tissue culture cell line were stably maintained in the tumor tissue. These results suggest that the Mallory body-containing cells frequently observed in man in alcoholic hepatitis and other degenerative liver diseases could, under appropriate environmental "promoting" conditions, be precursor cells in focal hepatocellular carcinoma formation.     

牛磺酸对扩张型心肌病大鼠心肌胶原重塑的影响

目的:探讨牛磺酸对呋喃唑酮扩张型心肌病(DCM)大鼠左室心肌胶原重塑的影响及其机制。方法:将60只大鼠分为3组,即正常对照组(C组)、DCM模型组(D组)和牛磺酸治疗组(T组),每组20只,C组按常规饲养,D组在饮水中加呋喃唑酮饲养,T组除加呋喃唑酮饲养外同时注射牛磺酸,饲养4周和8周后分2批经超声心动图检测大鼠心功能,测量大鼠左室内径和左室游离壁厚度;苏木精-伊红和VG染色分别观察大鼠心肌细胞和间质胶原纤维的变化;免疫组化和RT-PCR检测左室心肌基质金属蛋白酶1(MMP1)和基质金属蛋白酶组织抑制因子1(TI MP1)表达水平。结果:D组大鼠左心室内径增大、游离壁变薄,左室收缩功能下降;间质纤维明显增生;左室心肌MMP1表达水平明显上调及TI MP1表达水平明显下调。而T组大鼠左室结构和功能正常,心肌间质胶原无明显增生,MMP1表达水平明显下调及TI MP1表达水平明显上调。结论:牛磺酸能抑制呋喃唑酮DCM大鼠左室心肌胶原重塑,其机制可能是通过调节MMP1与TI MP1的平衡而起作用。     

Ear tumours induced by experimental carcinogenesis in the rat: excision prevents early death

1,2-dimethylhydrazine (DMH) is widely used to induce colorectal tumours in rodents. Some of the animals develop ear as well as colorectal tumours. Rats with large, ulcerated ear tumours are usually sacrificed before the completion of the experiment. In this experiment, fourty-six male Spraque-Dawley rats were injected with 1,2-dimethylhydrazine (21 mg/kg body weight) once a week for 27 weeks to study the histogenesis of colorectal carcinoma. Thirty-six developed ear tumours. Fourteen of the 36 tumours were larger than 2 cm in diameter. These developed between 20–26 weeks and were surgically excised 1–5 weeks later. Four rats died postoperatively. The surgical removal of large ear tumours permitted the completion of the large bowel experiment on schedule (i.e. 27 weeks) in 10 (28%) of the 36 rats with ear tumours.

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Résumé La 1,2 dimethylhydrazine (DMH) est largement utilisée pour induire des tumeurs colo-rectales chez les rongeurs. Quelques animaux développent des tumeurs de l'oreille au même titre que des tumeurs colo-rectales. Les rats porteurs de larges tumeurs exulcérées de l'oreille sont sacrifiés habituellement avant la fin de l'expérimentation. Dans cette étude, 46 rats mâles Spraque-Dawley ont reçu par injection de la 1,2 dimethylhydrazine (21 mg/kg de poids corporel) une fois par semaine durant 27 semaines afin d'étudier l'histo-génèse des cancers colo-rectaux. Trente-six ont développé des tumeurs de l'oreille, 14 de ces 36 tumeurs mesuraient plus de 2 cm de diamètre. Elles se développent entre la 20 et la 26e semaine et ont été excisées chirurgicalement 1 à 5 semaines plus tard. Quatre rats sont morts dans la période post-opératoire. L'excision chirurgicale des larges tumeurs de l'oreille a permis de compléter le programme d'expérimentation colique (sur 27 semaines) chez 10 (28%) des 36 rats porteurs des tumeurs de l'oreille.

     

青藤碱对胶原诱导型关节大鼠滑膜细胞增殖及凋亡影响的研究

目的研究青藤碱对胶原诱导型关节炎(CIA)大鼠关节炎症,滑膜增生、凋亡及突变型p53的影响,揭示青藤碱抗类风湿关节炎(RA)可能的作用途径。方法采用牛Ⅱ型胶原混合弗氏不完全佐剂于W istar大鼠尾根部注射,足肿后随机分为造模加生理盐水组、甲氨蝶呤(M TX)治疗组和青藤碱(SIN O)治疗组,采用容积法和计分法分别评价后肢肿胀度和四肢关节炎症程度;左前肢和右后肢近端第3足趾关节苏木素-伊红(H E)染色,评价中性粒细胞、淋巴细胞、浆细胞浸润、滑膜细胞增生和纤维组织增生的情况;对足肿胀和病理各项指标进行回归性分析。碱性磷酸酶标记法检测大鼠滑膜细胞凋亡;免疫组织化学法检测突变型p53的表达。比较M TX和SINO灌胃治疗后各项指标的差异。结果CIA大鼠造模后,炎症迅速发展,1周内即可达到肿胀高峰,然后逐渐消退,在第21～25天后又出现第2个炎症高峰。药物治疗17d后抑制CIA肢炎症的作用逐渐显现出来。M TX和SIN O都可明显抑制第2个炎症高峰,后肢肿胀度和四肢肿胀积分在35d与造模加生理盐水组差异有统计学意义(P<0.01);病理结果中,CIA大鼠关节表现为单个核炎症细胞浸润(包括中性粒细胞、淋巴细胞和浆细胞的浸润),滑膜细胞增生、纤维组织增生;足肿与淋巴细胞浸润,滑膜增生呈直线回归关系,其中以滑膜增生为主(P<0.01     

牛磺酸对大鼠局灶性脑缺血再灌注损伤的保护

目的探讨牛磺酸对大鼠局灶性脑缺血再灌注损伤的保护作用。方法 SD雄性大鼠44只,分为假手术组(4只),对照组(20只)牛磺酸组(20只)。应用Bederson评分方法对大鼠脑缺血6、24 h进行神经功能评分。激光多普勒血流仪测量脑血流变化。HE染色检测神经元核周体。结果牛磺酸组较对照组神经功能评分减小,神经功能改善;牛磺酸组缺血24 h后脑血流量增加,脑组织血流供应改善;假手术组脑组织未出现神经元坏死的特征,牛磺酸组神经元核周体损伤体积明显低于对照组(P<0.01)。结论牛磺酸对脑缺血再灌注损伤具有保护作用。     

慢性缺氧对肺外动脉胶原堆积及胶原基因表达的影响

模拟海拔５０００米连续低压缺氧７天复制大鼠肺动脉高压模型，观察结构重建的肺外动脉胶原含量及其基因表达的变化。结构表明：缺氧７天末，大鼠肺动脉压、右心室／左心室＋室间隔重量比值及肺外动脉湿干重量和羟脯氨酸含量均明显升高；经Ｎｏｒｔｈｅｒｎ杂交和斑点杂交分析无交叉和非特异性杂交的编码人Ｐｒｏａ１（Ｉ），Ｐｒｏａ１（Ⅲ）肽链的ｃＤＮＡ探针，进行ＤＮＡ－ＲＮＡ的斑点杂交显示，缺氧组织的Ｐｒｏａ１（Ｉ），ｐ