AC1及AC3抗白内障形成中晶状体谷胱甘肽代谢相关酶活性的变化

观察了亚硒酸钠,AC1,AC3对大鼠晶状体中谷胱甘肽过氧化物酶(GSH-Px),谷胱甘肽还原酶(GR)及谷胱甘肽硫转移酶(GST)的影响。结果表明,亚硒酸钠组大鼠的晶状体尚未混浊前已出现GSH-Px活性增高及GR和GST的活性降低。GR活性下降随白内障进展而加重。AC1及AC3均可使亚硒酸钠所致的酶活性变化逆转,但对正常晶状体的酶活性没有影响。     

抗白内障药物滴眼对亚硒酸钠性白内障的预防作用

 观察了三种化合物(抗氧化剂与自由基清除剂)对大鼠亚硒酸钠性白内障的滴眼预防作用。实验分为正常对照组、亚硒酸钠组及滴眼预防组。亚硒酸钠组及滴眼预防组系给12─13日龄的大鼠皮下注射亚硒酸钠,首次剂量为6μmol/kg体重,间日一次,逐次递增1μmol/kg体重,连续六次。预防组则为大鼠开眼后同时滴眼抗氧化剂与自由基清除剂。结果表明,三种化合物通过滴眼均能有效的防止亚硒酸钠性白内障的发生,白内障的发生率从95.8％降低至15％～43.5％。同时测定了各组晶状体中谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽还原酶(GSSG-R)及谷胱甘肽硫转移酶(GSH-S)的活性,结果表明,凡注射硒的大鼠晶状体中GSH-Px及GSSG-R的活性均比正常晶状体的高,接受抗氧化剂与自由基清除剂预防的大鼠晶状体中这两种酶的活性比未接受预防的大鼠晶状体中的低。单独注射硒的大鼠晶状体中GSH-S的活性比正常晶状体的高。接受预防的大鼠晶状体中此酶的活性和正常晶状体无差异,但比单独注射硒的大鼠晶状体中的低。     

晶状体生化的研究:正常和亚硒酸钠诱发白内障大鼠晶状体中与谷胱甘肽代谢有关的三种酶活性的测定

测定了用亚硒酸钠诱发的大鼠白内障晶状体中谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽还原酶(GSSG-R)和谷胱甘肽硫转移酶(GSH-S)的活性,并与正常晶休中这三种酶的活性作了比较。结果表明,核浊浑期晶状体中GSH-Px的活性比正常晶状体的高一倍,但在整个晶状体浑浊时降低,GSSG-R的活性变化与GSH-PX相似,这两种酶在代谢上是相关的。GSH-S的活性在核浑浊期不改变,但在完全浑浊后降低。     

AC1及AC3对白内障形成中晶状体氧化还原物质及硒含量的变化

观察了AC1和AC3对抗亚硒酸钠性白内障形成过程中晶状体的脂类过氧化作用,非蛋白质疏基水平及硒含量。结果表明,亚硒酸钠组大鼠,在晶状体混浊出现前已发生脂类过氧化作用及硒含量的明显增加,非蛋白质巯基含量的显著降低,并持续至核混浊期;而同时接受AC1或AC3的大鼠,晶状体非蛋白质巯基水平初期降低,然后逐渐恢复至正常。AC1可有效的对抗亚硒酸钠所致的脂类过氧化作用增加,而AC3的对抗效应需一定剂量及时程,两者对晶状体硒含量均无明显影响。     

硒性白内障大鼠模型晶状体中GR和GSH-Px的表达

 为探讨硒性白内障大鼠晶状体中谷胱甘肽过氧化物酶 (GSH Px)和谷胱甘肽还原酶 (GR)的活性调节在硒性白内障形成中的作用及调节方式 ,采用半定量RT PCR方法 ,比较正常晶状体、核中心混浊晶状体 (核白 )和完全混浊晶状体 (全白 )中GSH Px和GR的mRNA水平及酶活性的变化 .研究发现 ,核白晶状体中 2种酶的活性和mRNA水平均升高 ,其中酶活性的升高幅度小于mRNA水平 .随着白内障的发展 ,2种酶的活性和mRNA水平均逐渐下降 .至晶状体全白时 ,2种酶的活性均显著低于正常 ;全白时GR的mRNA水平降至正常 ,GSH Px的mRNA水平则仍高于正常 .结果表明 ,硒性白内障形成与细胞内GSH Px和GR的活性调节密切相关 ,GSH Px和GR的活性调节可能主要发生在转录水平     

不同剂量白藜芦醇对糖尿病性白内障大鼠晶状体抗氧化酶活力的影响

目的:探究不同剂量白藜芦醇对糖尿病性白内障大鼠晶状体抗氧化酶活力的影响。方法:75只5周龄健康SPF级雄性SD大鼠按照随机数字表法分为正常对照组、模型组,白藜芦醇低剂量组,白藜芦醇中剂量组和白藜芦醇高剂量组,每组各15只。五组大鼠均给予常规适应性喂养,模型组和白藜芦醇低、中、高剂量组大鼠采用链脲佐菌素(STZ)以60 mg/kg的给药剂量制作糖尿病大鼠模型,成模后白藜芦醇低剂量组按20 mg/kg、白藜芦醇中剂量组按50 mg/kg、白藜芦醇高剂量组按100 mg/kg的给药剂量每日给予白藜芦醇灌胃。观察12周后5组大鼠晶状体的混浊程度,检测血糖、体重后处死大鼠,检测晶状体内超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)以及过氧化氢酶(CAT)的活性改变。结果:随着白藜芦醇剂量的升高,白藜芦醇低、中、高剂量组大鼠的血糖逐渐降低而体重逐渐升高,且组间比较均具有统计学差异(P0.05)。三组不同剂量白藜芦醇干预组大鼠晶状体的浑浊程度均低于模型组,且白藜芦醇高剂量组大鼠晶状体的浑浊程度最低,差异均具有统计学意义(P0.05)。白藜芦醇低、中、高剂量组大鼠SOD、GSH-PX和CAT酶活力与模型组大鼠相比均明显升高,而与正常对照组相比均明显降低(均P0.05)。随着白藜芦醇剂量的升高,白藜芦醇低、中、高剂量组大鼠SOD、GSH-PX和CAT酶活力逐渐升高,且组间比较均具有统计学差异(P0.05)。结论:高剂量白藜芦醇可更为明显地降低血糖浓度,提高晶状体SOD、GSH-Px及CAT酶活力,改善糖尿病性白内障晶状体的浑浊程度。     

三硝基甲苯中毒性白内障动物模型的建立及其发病机理的初步研究

反复多次给大鼠皮下注射20％三硝基甲苯(TNT)甘油:水混悬液,染毒15个月后21％动物发生白内障,其裂隙灯检查结果与人TNT性白内障基本相似,同时注射甘油:水溶剂的对照组大鼠无一例发生白内障。染毒10个月的大鼠,其晶状体LPO增高,GSH-P_X及GST活性降低,GR活性无变化,而GSH含量明显增加;注射TNT后肝脏LPO值、GSH含量、GSH-P_X、GR及GST活性均明显增高。本文结果提示,TNT中毒性白内障的形成可能系TNT及其代谢产物直接作用于晶状体,造成昌状体氧化损伤所致。TNT白内障大鼠模型的建立亦为深入探讨其发病机理及防治奠定了基础。     

去卵巢对骨质疏松大鼠皮肤衰老的影响

目的用去卵巢大鼠构建的骨质疏松症模型是研究绝经后骨质疏松疾病的最适模型,然而大鼠卵巢去除后对皮肤的影响如何,这方面的研究甚少。本研究旨在观察去卵巢对大鼠皮肤衰老指标的影响。方法 3月龄健康SD雌性大鼠20只,随机分为假手术组(Sham组)和去卵巢组(OVX组),卵巢去除后3个月,测定血清雌二醇,以及皮肤组织中与衰老相关的生化指标如过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性以及丙二醛(MDA)、羟脯氨酸(HYP)、脂褐质(LF)含量,并观察皮肤组织病理学变化,用计算机图像分析系统定量分析。结果 OVX组大鼠血清雌二醇水平显著降低;组织病理学观察显示OVX组表皮、真皮厚度较Sham组显著变薄(P0.01),皮肤胶原纤维减少,排列疏松;与Sham组相比,OVX组大鼠皮肤CAT、GSH-Px和SOD活性显著降低(P0.01),MDA含量较Sham组明显增加(P0.01),皮肤组织中HYP含量明显减少,LF含量显著增多(P0.01)。结论 3月龄大鼠卵巢去除后3个月可导致皮肤衰老,可能是研究绝经后皮肤衰老的适宜模型。     

葡萄籽原花青素对大鼠烟雾吸入性肺损伤的保护作用

目的:探讨葡萄籽原花青素(grape seed proanthocyanidin extract,GSPE)对大鼠烟雾吸入性肺损伤的保护作用。方法:将48只大鼠随机分为正常对照组、烟雾吸入性肺损伤模型组、GSPE治疗组(500mg/kg),分别于致伤后2、4、12、24h监测动脉血气分析,分批处死大鼠,分别进行肺组织湿/干重测定,制备组织匀浆测超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、一氧化氮合酶(NOS)活性及一氧化氮(NO)、丙二醛(MDA)含量和HE染色。结果:与模型组比较,GSPE治疗组各时间点动脉血氧分压均显著升高(P<0.01),肺组织含水量显著降低(P<0.05),肺组织中SOD活性均明显升高(P<0.01),GSH-Px活性均明显升高(P<0.05),NOS活性及NO、MDA含量均明显降低(P<0.05)。肺组织病理学观察GSPE治疗组较模型组肺间质水肿减轻,炎性细胞浸润减少。结论:GSPE可能通过其显著增加组织的抗氧化能力而对烟雾吸入性肺损伤起到一定保护作用。     

晶状体生化的研究 平阳霉素诱发大鼠白内障的研究

 本文报道间日经皮下注射平阳霉素(Pingyangmycin)(25μg/10g体重)于出生后四日之乳鼠可诱发白内障,其诱发率为84.6％。患白内障时晶状体中可溶性蛋白质含量明显降低。经Sephadex G-200柱层析可见βH,γ晶体蛋白降低,α晶体蛋白则相对升高。经10％聚丙烯酰胺凝胶电泳及等电聚焦电泳可见γ晶体蛋白改变明显,这些结果和我们用半乳糖及亚硒酸钠诱发白内障所得结果一致。     

Exercise training with ageing protects against ethanol induced myocardial glutathione homeostasis

Glutathione plays a central role in the maintenance of cellular antioxidant defense. The alterations in the glutathione and associated recyclic enzymes caused by both exercise training and ethanol are well documented; however, their interactive effects with age are not well understood. Therefore, the influence of ageing and the interactive effects of exercise training and ethanol on the myocardial glutathione system in 3 months and 18 months old rats were examined. The results showed a significant (p<0.01) reduction in GSH content, Se and non-Se GSH-Px, GR and GST activities in the myocardium of rat with age. A significant increase (p<0.05) in the activities of these enzymes was observed in both age groups of rats in response to exercise training. This exercise-induced elevation of Se and non-Se GSH-Px and GR activities was more pronounced in the 18 months old rats when compared to 3 months old rats. Ethanol consumption significantly (p<0.05) reduced the GSH content, Se and non-Se GSH-Px and GR activities in both age groups of rats. In contrast, ethanol consumption significantly (p<0.05) increased the activity of GST. The combined action of exercise plus ethanol significantly (p<0.05) elevated the GSH content, Se and non-Se GSH-Px, GR and GST activities when compared to the ethanol treated rats in both age groups, indicating the suppression of ethanol-induced oxidative stress by exercise training. In conclusion, there was a compensatory myocardial response lessening ethanol-induced oxidative stress by exercise training, which seemed to result from the higher activity of glutathione recycling and utilizing enzymes, which may be critical for preventing chronic oxidative damage to the myocardium during ageing and even due to ethanol consumption.     

Protective effect of caffeic acid phenethyl ester (CAPE) on lipid peroxidation and antioxidant enzymes in diabetic rat liver

The aim of this study was to examine the effect of caffeic acid phenethyl ester (CAPE) on lipid peroxidation (LPO) and the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in the liver of streptozotocin (STZ)-induced diabetic rats. Twenty-seven rats were randomly divided into three groups: group I, control non-diabetic rats (n = 9); group II, STZ-induced, untreated diabetic rats (n = 8); group III, STZ-induced, CAPE-treated diabetic rats (n = 10), which were intraperitoneally injected with CAPE (10 microM kg(-1) day(-1)) after 3 days followed by STZ treatment. The liver was excised after 8 weeks of CAPE treatment, the levels of malondialdehyde (MDA) and the activities of SOD, CAT, and GSH-Px in the hepatic tissues of all groups were analyzed. In the untreated diabetic rats, MDA markedly increased in the hepatic tissue compared with the control rats (p < 0.0001). However, MDA levels were reduced to the control level by CAPE. The activities of SOD, CAT, and GSH-Px in the untreated diabetic group were higher than that in the control group (p < 0.0001). The activities of SOD and GSH-Px in the CAPE-treated diabetic group were higher than that in the control group (respectively, p < 0.0001, p < 0.035). There were no significant differences in the activity of CAT between the rats of CAPE-treated diabetic and control groups. Rats in the CAPE-treated diabetic group had reduced activities of SOD and CAT in comparison with the rats of untreated diabetic group (p < 0.0001). There were no significant differences in the activity of GSH-Px between the rats of untreated diabetic and CAPE-treated groups. It is likely that STZ-induced diabetes caused liver damage. In addition, LPO may be one of the molecular mechanisms involved in STZ-induced diabetic damage. CAPE can reduce LPO caused by STZ-induced diabetes.     

Effect of neonatal hypoxia on the development of hepatic lipase in the rat

Increases in plasma lipids occur during hypoxia in suckling but not in weaned rats and may result from altered hepatic enzyme activity. We exposed rats to 7 days of hypoxia from birth to 7 days of age (suckling) or from 28 to 35 days of age (weaned at day 21). Hypoxia led to an increase in hepatic lipid content in the suckling rat only. Hepatic lipase was decreased to approximately 45% of control in 7-day-old rats exposed to hypoxia but not in hypoxic 35-day-old rats. Hypoxic suckling rats also had a 50% reduction in lactate dehydrogenase activity, whereas transaminase activity and CYP1A and CYP3A protein content were not different between hypoxic and normoxic groups. Additional rats were studied 7 and 14 days after recovery from hypoxic exposure from birth to 7 days of age; hepatic lipase activity had recovered to 85% by 7 days and to 100% by 14 days in the rats previously exposed to hypoxia. Administration of dexamethasone to neonatal rats to simulate the hyperglucocorticoid state found in hypoxic 7-day-old rats led to a moderate decrease ( approximately 75% of control) in hepatic lipases. Developmentally, in the normoxic state, hepatic lipases increased rapidly after birth and reached levels more than twofold that of the newborn by 7 days of age. Hypoxia delays the maturation of hepatic lipases. We suggest that the decrease in hepatic lipase activity contributes to hyperlipemia in the hypoxic newborn rats.     

Influence of intestinal microflora on the tryptic activity during lactation in rats

On comparing germ-free and conventional rats, inactivation of the tryptic activity was found to take place in the caecum of conventional adult rats only. A microbial intestinal inactivation of the tryptic activity was established in suckling conventional rats within 10 days after birth. At 3 weeks of age, suckling germ-free rats were found to have less faecal tryptic activity than their early-weaned littermates.     

The effects of cold acclimation and nitric oxide on antioxidative enzymes in rat pancreas

Alterations of pancreatic antioxidative defense (AD) and possible nitric oxide (NO) role in AD organization of adult rats receiving l-arginine.HCl (2.25%) or N(omega)-nitro-l-arginine methyl ester (L-NAME.HCl, 0.01%) as drinking liquids and maintained at room (22+/-1 degrees C) or low (4+/-1 degrees C) temperature for 45 days were studied. For that purpose, copper, zinc- and manganese superoxide dismutase (CuZnSOD, MnSOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and glutathione reductase (GR) activities were determined. Cold-induced decrease of CuZnSOD was inhibited with L-NAME, while l-arginine produced the same effect as cold in both supplemented groups. Cold acclimation elevated GSH-Px activity. l-Arginine and L-NAME expressed no effect on GSH-Px in rats kept at room temperature. L-NAME additionally elevated cold-induced GSH-Px activity, l-arginine expressing a similar trend. Cold-induced increase in GST activity was inhibited by L-NAME, while l-arginine inhibited this enzyme in both supplemented groups. Cold acclimation increased GR activity in control and L-NAME-treated group and l-arginine expressed a similar trend. Neither of the treatments affected MnSOD and CAT activities. Cold-induced changes of pancreatic AD were additionally affected by the alterations in l-arginine-NO-producing pathway. Some AD changes in the same direction with l-arginine or L-NAME point to the complexity of nitrogen compounds metabolism and function, accompanied by tissue-specific response.     

Effects of progesterone and estradiol benzoate on glutathione dependent antioxidant enzyme activities in the brain of female rats.

The activities of glutathione dependent antioxidant enzymes were measured in subcellular fractions of whole brain homogenates prepared from ovariectomized (OVX) female rats, untreated or treated 2 h or 24 h prior to sacrifice with a single dose of 2 mg progesterone (P) or 5 micrograms estradiol benzoate (EB). Glutathione peroxidase (GSH-Px) activity was not changed following systemic administration of EB, but P increased GSH-Px in the brain of OVX rats 24 h after the treatment. The activity of glutathione reductase (GR) was suppressed by EB short time, only 2 h following treatment, whereas P increased the enzyme activity 24 h after treatment. On the other hand, the activities of catalase (CAT) and glutathione-S-transferase (GST) were not changed following systemic administration of EB or P. The present work was carried out to study the involvement of ovarian steroids, especially P, in the control of GSH-Px and GR activities, and our results suggest that oxidative stress in the brain of female rats may be modulated by the level of progesterone.     

Exercise training with ageing protects against ethanol induced myocardial glutathione homeostasis

Glutathione plays a central role in the maintenance of cellular antioxidant defense. The alterations in the glutathione and associated recyclic enzymes caused by both exercise training and ethanol are well documented; however, their interactive effects with age are not well understood. Therefore, the influence of ageing and the interactive effects of exercise training and ethanol on the myocardial glutathione system in 3 months and 18 months old rats were examined. The results showed a significant (p<0.01) reduction in GSH content, Se and non-Se GSH-Px, GR and GST activities in the myocardium of rat with age. A significant increase (p<0.05) in the activities of these enzymes was observed in both age groups of rats in response to exercise training. This exercise-induced elevation of Se and non-Se GSH-Px and GR activities was more pronounced in the 18 months old rats when compared to 3 months old rats. Ethanol consumption significantly (p<0.05) reduced the GSH content, Se and non-Se GSH-Px and GR activities in both age groups of rats. In contrast, ethanol consumption significantly (p<0.05) increased the activity of GST. The combined action of exercise plus ethanol significantly (p<0.05) elevated the GSH content, Se and non-Se GSH-Px, GR and GST activities when compared to the ethanol treated rats in both age groups, indicating the suppression of ethanol-induced oxidative stress by exercise training. In conclusion, there was a compensatory myocardial response lessening ethanol-induced oxidative stress by exercise training, which seemed to result from the higher activity of glutathione recycling and utilizing enzymes, which may be critical for preventing chronic oxidative damage to the myocardium during ageing and even due to ethanol consumption.     

Blood dopamine beta-hydroxylase activity and noradrenaline levels in the developing white rat.

Dopamine beta-hydroxylase (DBH) (3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase (beta-hydroxylating) (EC 1.14.17.1) activity in serum of blood obtained by decapitation of white rats at 19, 20, and 21 days in utero, immediately after birth, and postnatally to 70 days, was measured. Noradrenaline (NA) and DBH in plasma from undisturbed, cannulated, postweaning rats were also assayed. During the last few days in utero and the first 2 postnatal days serum DBH activity tripled and then remained elevated during the suckling period. Upon weaning, serum DBH activity declined at first precipitously and then more slowly, until the adult level was reached around 70 days of age. This postweaning decrease in DBH activity was also observed with the cannulated animals. In contrast, plasma NA levels remained low and constant throughout the postweaning period. In suckling rats treated with 6-hydroxydopamine from 2 to 12 days of age, serum DBH activity decreased to less than half its initial value by day 8. It is suggested that the observed changes in serum DBH activity in fetal and postnatal rats reflect ontogenetic changes in sympathetic nerve terminals and that they are probably not correlated with release of NA.