猴头菌对实验大鼠胃粘膜保护作用的研究

探讨猴头菌对实验大鼠胃牯膜损伤的保护作用及可能机制。方法：在无水乙醇形成大鼠胃牯膜损伤模型前后．应用猴头菌给予预防和治疗．观察胃粘膜损伤程度及病理改变：并检测胃粘膜氮基己糖及血浆胃泌素含量。结果：预服猴头菌2周后溃疡抑制率为62％．治疗2周后溃疡抑制率为91％：猴头菌能增进大鼠食欲,并可明显减轻胃牯膜的充血、出血,水肿和坏死：减轻粘膜下炎细胞浸润：促进粘膜氮基己糖的恢复：防止胃泌素的升高。结论：猴头菌对胃粘膜有良好的细胞保护作用。     

Hydroxyl radical scavenger ameliorates cisplatin-induced nephrotoxicity by preventing oxidative stress, redox state unbalance, impairment of energetic metabolism and apoptosis in rat kidney mitochondria

Nephrotoxicity is the major dose-limiting factor of cisplatin chemotherapy. Reactive oxygen species generated in mitochondria are thought to be the main cause of cellular damage in such injury. The present study examined, in vivo, the protective potential of the hydroxyl radical scavenger dimethylthiourea (DMTU) against cisplatin-induced effects on renal mitochondrial bioenergetics, redox state and oxidative stress. Adult male Wistar rats (200 to 220 g) were divided into four groups of eight animals each. The control group was treated only with an intraperitoneal (i.p.) injection of saline solution (1 ml/100 g body weight). The second group was given only DMTU (500 mg/kg body weight, i.p, followed by 125 mg/Kg, i.p., twice a day until they were killed). The third group was given a single injection of cisplatin (10 mg/kg body weight, i.p.). The fourth group was given DMTU (500 mg/kg body weight, i.p.), just before the cisplatin injection (10 mg/kg body weight, i.p.), followed by injections of DMTU (125 mg/kg body weight, i.p.) twice a day until they were killed. Animals were killed 72 h after the treatment. Besides not presenting any direct effect on mitochondria, DMTU substantially inhibited cisplatin-induced mitochondrial injury and cellular death by apoptosis, suppressing the occurrence of acute renal failure. All the following cisplatin-induced effects were prevented by DMTU: (1) increased plasmatic levels of creatinine and blood urea nitrogen (BUN); (2) decreased ATP content, calcium uptake and electrochemical potential; (3) oxidation of lipids, including cardiolipin; and oxidation of proteins, including sulfhydryl, and aconitase enzyme, as well as accumulation of carbonyl proteins; (4) depletion of the antioxidant defense (NADPH and GSH) and (5) increased activity of the apoptosis executioner caspase-3. Our findings show the important role played by mitochondria and hydroxyl radicals in cisplatin-induced nephrotoxicity, as well as the effectiveness of DMTU in preventing the renal mitochondrial damage caused by cisplatin. These results strongly suggest that protection of mitochondria by hydroxyl radical scavengers may be an interesting approach to prevent the kidney tissue damage caused by cisplatin-chemotherapy.     

腺苷预处理和缺血预处理心肌保护效果对比研究

目的探讨心肌腺苷预处理和缺血预处理对离体大鼠心脏缺血/再灌注后心肌功能的影响。方法采用离体大白鼠工作心脏模型,比较腺苷预处理和缺血预处理对心肌缺血再灌前、后左室收缩压(LVSP)、左室舒张末期压(LVDEP)、左心室内压上升及下降最大速率(±dp/dtmax)、主动脉压(AP)、冠脉流量(CF)、心输出量(CO)、每搏心输出量(SV)和冠脉流出液乳酸脱氢酶(LDH),心肌三磷酸腺苷(ATP)含量、超氧化物歧化酶(SOD)活性、脂质过氧化物(LPO)含量及自灌注停搏液至完全停搏的时间(AT)。结果3组大鼠AT间差异有显著性意义(P<0.05),且Control组与其他两组间差异均有显著性意义(P<0.05)。3组大鼠停搏前、复跳后30minAP、LVSP、LVDEP、±dp/dtmax、SV、CF、Co间差异均有显著性意义(P<0.05)。3组大鼠ATP、SOP、LPO、LDH间差异亦均有显著性意义(P<0.05)。结论腺苷预处理和缺血预处理后产生相似的心肌保护作用,明显促进心肌缺血再灌后心肌功能的恢复,增进心脏的收缩功能、心肌ATP含量和SOD活性的恢复,减少LDH的漏出。腺苷预处理对心脏模拟体外循环的缺血再灌注损伤具有保护作用,具有临床应用价值。     

低氧预适应对大鼠肝切除后残肝组织凋亡相关蛋白表达的影响及意义

目的 观察低氧预适应对大鼠肝切除术后残肝组织凋亡相关蛋白细胞色素C和caspase 3表达的影响及其意义.方法 采用SD大鼠肝切除模型研究低氧预适应对残肝组织凋亡相关蛋白表达的影响及意义.将SD大鼠随机分为对照组(NC组)、单纯肝切除组(HR组)和低氧预适应组+肝切除组(HP组),每组24只.HP组术前用10％氮氧混合气体处理90 min,分别于术后1h、6h、12 h、24 h处死大鼠取肝脏标本,取门静脉血检测肝功能,Western-Blot法测定肝切除大鼠残肝组织细胞色素C和caspase 3蛋白的表达,并在电镜下观察各组肝细胞形态学改变、线粒体损伤程度等.结果 HP组血清ALT和AST水平显著低于HR组,差异有统计学意义(P＜0.05);HP组各时段的肝功能明显优于HR组;HP组各时段细胞色素C和caspase 3蛋白表达明显低于HR组,透射电镜下HR组肝细胞出现典型的凋亡征象,而HP组肝细胞无明显凋亡形态.结论 HP对肝切除后残肝组织的肝细胞凋亡有明显的抑制作用;可能是通过下调细胞色素C和caspase 3蛋白的表达、减轻线粒体损伤途径而发挥其保护作用.     

Clusterin,other extracellular chaperones,and eye disease

Proteostasis refers to all the processes that maintain the correct expression level, location, folding and turnover of proteins, essential to organismal survival. Both inside cells and in body fluids, molecular chaperones play key roles in maintaining proteostasis. In this article, we focus on clusterin, the first-recognized extracellular mammalian chaperone, and its role in diseases of the eye. Clusterin binds to and inhibits the aggregation of proteins that are misfolded due to mutations or stresses, clears these aggregating proteins from extracellular spaces, and facilitates their degradation. Clusterin exhibits three main homeostatic activities: proteostasis, cytoprotection, and anti-inflammation. The so-called "protein misfolding diseases” are caused by aggregation of misfolded proteins that accumulate pathologically as deposits in tissues; we discuss several such diseases that occur in the eye. Clusterin is typically found in these deposits, which is interpreted to mean that its capacity as a molecular chaperone to maintain proteostasis is overwhelmed in the disease state. Nevertheless, the role of clusterin in diseases involving such deposits needs to be better defined before therapeutic approaches can be entertained. A more straightforward case can be made for therapeutic use of clusterin based on its proteostatic role as a proteinase inhibitor, as well as its cytoprotective and anti-inflammatory properties. It is likely that clusterin works together in this way with other extracellular chaperones to protect the eye from disease, and we discuss several examples. We end this article by predicting future steps that may lead to development of clusterin as a biological drug.     

Rocket ＂Eruca sativa＂： A salad herb with potential gastric anti-ulcer activity

AIM： To validate gastric anti-ulcer properties of Rocket ＂Eruca sativa＂ on experimentally-induced gastric secretion and ulceration in albino rats. METHODS： Gastric acid secretion studies were undertaken using pylorus-ligated rats. Gastric lesions in the rats were induced by noxious chemicals including ethanol, strong alkalis, indomethacin and hypothermic restraint stress. The levels of gastric wall mucus （GWM）, nonprotein sulfhydryls （NP-SH） and malondialdehyde （MDA） were also measured in the glandular stomach of rats following ethanol administration. The gastric tissue was also examined histologically. The extract was used in two doses （250 and 500 mg/kg body weight） in all experiments. RESULTS： In pylorus-ligated Shay rats, the ethanolic extract of Rocket ＂Eruca sativa L.＂ （EER） significantly and dose-dependently reduced the basal gastric acid secretion, titratable acidity and ruminal ulceration. Rocket extract significantly attenuated gastric ulceration induced by necrotizing agents （80% ethanol, 0.2 mol/L NaOH, 25% NaCl）, indomethacin and hypothermic restraint stress. The anti-ulcer effect was further confirmed histologically. On the other hand, the extract significantly replenished GWM and NP-SH levels, as well as the MDA level significantly reduced by extract pretreatment. CONCLUSION： Rocket extract possesses antisecretory, cytoprotective, and anti-ulcer activities against experimentally-induced gastric lesions. The anti-ulcer effect is possibly through prostaglandinmediated activity and/or through its anti-secretory and antioxidant properties.     

阿魏酸钠对婴幼儿体外循环血管内皮功能的保护作用

目的 观察婴幼儿先天性心脏病心肺转流术(CPB)围手术期一氧化氮(NO)、内皮素(ET-1)和循环内皮细胞(CEC)水平的变化,初步探讨阿魏酸钠对血管内皮功能的保护作用.方法 60例先天性心脏病病儿随机分为阿魏酸钠组(S组)和对照组(C组)各30例.S组于体外循环前静脉滴注阿魏酸钠注射液8 mg/kg,C组予等量平衡盐溶液,检测CPB前(TO)、30 min(T1)、结束时(T2)、手术后2h(T3)、6 h(T4)5个时间点血浆NO和ET浓度,以及T0和T2两个时间点的CEC变化.结果 两组间T0比较差异不明显,12与T0比较CEC浓度均升高明显;T2时与C组比较,S组CEC升高幅度明显被抑制,差异有统计学意义(P<0.05).两组血浆N0浓度T1均降低,差异有统计学意义,组间比较无统计学意义(P>0.05),T2、T3、T4时间点两组NO浓度均有所上升,但均低于T0,差异明显,S组NO降低程度比C组小(P<0.05).两组T1时ET-1稍有降低,随后ET-1升高明显(P<0.01);S组T1、T2、T3、T4时间点均低于C组,差异有统计学意义(P<0.05或P<0.01).结论 体外循环手术可造成NO/ET失平衡状态,CEC数明显增加,证实CPB后存在着血管内皮功能的损伤.阿魏酸钠组术后NO下降幅度,ET、CEC升高的幅度,明显较对照组小,阿魏酸钠可有效拮抗ET的分泌,促进NO的生成,对婴幼儿体外循环手术有较好的血管内皮功能保护作用.

Abstract：

Objective Cardiopulmonary bypass (CPB) and its related ischemia reperfusion injury may cause endothelial cell injury.To study the protective effects of sodium ferulate in vascular endothelial function during CPB by testing the changes of vascular endothelial cell( CEC),nitric oxide( NO) and endothelin-1 ( ET-1 ) in children with congenital heart disease.Methods Sixty patients with congenital heart disease,including 28 males and 32 females were studied.The mean age was (19.7 ±10.4) months and body weight (10.5 ±6.1) kg.There were 37 VSD,8 ASD,7 TOF,5 TAPVC and 3 CAVC,among them 26 patients had pulmonary hypertension.They were randomly divided in to two groups:sodium ferulate group ( group S,n = 30),and control group ( group C,n =30) .Sodium ferulate (8 mg/kg) was given intravenously before CPB.Blood samples were taken from the arterial line at following time points:before CPB (TO),bypass 30 min(Tl ),the termination of CPB (T2 ),2h after operation ( T3 ) and 6h after operation ( T4 ),respectively for determination the concentration of vascular endothelial cell (CEC) in the blood,the concentration of nitric oxide (NO) and endothelin-1 ( ET-1) in the plasma.Results There were no significant difference for the two groups regarding above parameters at TO ( P > 0.05).The level of CEC was significantly elevated after CPB in both groups ( P < 0.05 ) .CEC were lower at T2 in group S than in group C ( P < 0.05 ) .NO was decreased in both groups,but was higher in group S at T2,T3 and T4 ( P < 0.05 ) .The concentration of plasma ET-1 was not significantly different before CPB,but there was a slight decrease at T1,and then it was significantly increased in both groups (P<0.05).But it was lower in group S than in group C at T1,T2,T3 and T4(P<0.05 orP<0.01).Conclusion There was severe endothelial cell damage during CPB.Sodium Ferulate can effectively antagonize the secretion of ET-1 to promote the formation of NO.Therefore,it reduces CPB-induced endothelial cell damage and protects vascular endothelial function during CPB.     

Alcohol exposure and mechanisms of tissue injury and repair

Tissue injury owing to acute and chronic alcohol consumption has extensive medical consequences, with the level and duration of alcohol exposure affecting both the magnitude of injury and the time frame to recovery. While the understanding of many of the molecular processes disrupted by alcohol has advanced, mechanisms of alcohol-induced tissue injury remain a subject of intensive research. Alcohol has multiple targets, as it affects diverse cellular and molecular processes. Some mechanisms of tissue damage as a result of alcohol may be common to many tissue types, while others are likely to be tissue specific. Here, we present a discussion of the alcohol-induced molecular and cellular disruptions associated with injury or recovery from injury in bone, muscle, skin, and gastric mucosa. In every case, the goal of characterizing the sites of alcohol action is to devise potential measures for protection, prevention, or therapeutic intervention.     

Heme oxygenase-1 mediates cytoprotective effects of immunostimulation in microglia

Microglia are brain-resident immune cells playing a pivotal role in the neuroinflammation. Previously, it has been shown that immunostimulation protects microglial cells against nitric oxide toxicity. Herein, we report that heme oxygenase-1 (HO-1) mediates the protective effects of immunostimulation. Pro-inflammatory activation of BV-2 microglial cells with endotoxin lipopolysaccharide (LPS) conferred a protection against various cytotoxic stimuli, whereas anti-inflammatory cytokines such as IL-4 and IL-10 were without effects. The LPS-induced cytoprotection was accompanied by HO-1 induction. The cytoprotective effect of LPS treatment was significantly attenuated by co-treatment with a HO-1 inhibitor, zinc protoporphyrin. Adenoviral expression of HO-1 in microglial cells was similarly cytoprotective, indicating that HO-1 mediates the cytoprotective effects of pro-inflammatory stimulation. Additional experiments revealed the involvement of carbon monoxide (CO) and iron, products of HO-1-mediated heme degradation, in the cytoprotective effect of LPS. Taken together, our results suggest that immunostimulation of microglia with LPS provides cytoprotective effects via HO-1 induction followed by the generation of CO and iron.     

Gastric Cytoprotection in Man by Prostaglandin E2

In healthy volunteers, the effects of topical prostaglandin E₂ (PGE₂), 1 mg, on transmucosal potential difference (PD), mucus secretion, and epithelial cell turnover were investigated. PGE₂ increased gastric PD by 10 mV on an average and stimulated mucus secretion of the stomach by 50%. In contrast, epithelial cell turnover remained unchanged. Gastric output of H⁺ decreased, whereas the outputs of volume, Na⁺, and CI^- rose in response to PGE₂, which effects would be compatible with increased secretion of bicarbonate. Topical administration of ethanol 40% (vol/vol) reduced PD by 25 mV (ΔPD_E) and enhanced epithelial cell shedding by 350% with concomitant discharge of mucus from stomach epithelium. Pretreatment of the stomach with 1 mg PGE₂ prevented the ethanol-dependent epithelial cell exfoliation, indicating gastric mucosal cytoprotection. ΔPD_E and discharge of mucus were not significantly altered by PGE₂. We conclude that gastric cytoprotection by PGE₂ in man might be mediated by stimulation of mucus and/or bicarbonate production.