Inhibition of injury induced intimal hyperplasia by saralasin in rats.

Increasing evidence points toward local production of renin and angiotensinogen in the artery wall. Because angiotensin converting enzyme (ACE) inhibitors have been shown to block intimal hyperplasia after arterial injury in the rat, it has been suggested that angiotensin II is an important mediator of the proliferative response to vascular injury. To prove that previous observations with use of ACE inhibitors are a result of effects on local angiotensin levels versus nonspecific drug effects, we tested the ability of an unrelated drug, the angiotensin II receptor antagonist saralasin, to similarly block intimal hyperplasia after aortic injury in the rat. Balloon catheter aortic denudation was performed in 28 rats pharmacologically treated for 14 days after surgery and split into four groups: group 1, saralasin 360 micrograms/kg/hr intravenously; group two, normal saline 0.5 mm3/hr intravenously; group 3, captopril 100 mg/kg/day orally; and group 4, heparin 50 U/kg/hr intravenously. Animals were killed and aortas were perfusion fixed at physiologic pressure 14 days after denudation. Cross-sectional intima-to-media ratios were calculated by computerized planimetry. Compared with saline controls, saralasin inhibited intimal hyperplasia 45% (p less than 0.001), captopril 59% (p less than 0.001), and heparin 68% (p less than 0.001). A reduction in total intimal area was also evident in animals treated with saralasin (p less than 0.01). Blood pressure in the group treated with captopril decreased from 107.4 +/- 3.9 to 96.3 +/- 4.3 mm Hg (p less than 0.01) after 6 days, whereas saralasin and heparin had no effect on blood pressure. Weight gain during the study was reduced in groups treated with captopril and heparin but not in the group treated with saralasin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of angiotensin converting enzyme (ACE) and angiotensins on human sperm functions

Summary.  The presence of components of the renin angiotensin system (RAS) and specific receptors of angiotensin II in the female and male reproductive tract supports the hypothesis that reproductive functions may be controlled by RAS. Therefore, the present study investigated the influence of ACE and angiotensins on sperm functions and the sperm–egg interaction.
The experiments did not indicate direct effects of ACE on the capacitation process or acrosome reaction. Release of ACE from human spermatozoa during capacitation was not related to their ability to undergo acrosome reaction after stimulation with ionophore. Therefore, ACE release does not seem to be a useful clinical marker for human sperm capacitation. However, decreased binding of human spermatozoa to the oolemma of zona-free hamster oocytes after inhibition of ACE by captopril indicates that kininase II is involved in sperm–egg interactions. In contrast to other studies, incubation with captopril had no influence on sperm binding to the zona pellucida. Because effects of ACE on sperm–egg interactions but not on capacitation or acrosome reaction were observed, several experiments were performed to study the influence of substrates and products on the acrosome reaction. Angiotensin II induced the acrosome reaction dose-dependently, whereas angiotensin I had no effect on the acrosome reaction. The effect of angiotensin II on acrosome reaction seems to be calcium-dependent and mediated by protein kinases. Since a specific type 2 angiotensin II receptor inhibits the acrosome reaction induced by angiotensin II, this subtype of receptors may be present at the surface of sperm heads. Another clue for the presence of type 2 receptors on human spermatozoa is the finding that pertussis toxin did not inhibit the angiotensin II induced acrosome reaction. In contrast to type 1 angiotensin II receptors, type 2 receptors are known to be G-protein independent.     

Role of angiotensin II in tubulointerstitial injury.

The renin angiotensin system (RAS) has been implicated in tubulointerstitial injury in a range of clinical and experimental settings. Angiotensin II, the major effector molecule of the RAS, in addition to its effects on systemic blood pressure and intrarenal hemodynamics, also acts as a local hormone and growth factor to modulate renal function and pathology. There is increasing evidence for a pivotal role of this hormone in influencing renal tubular and interstitial function and structure including regulation of multiple cytokines and chemokines, promoting infiltration of monocytes/macrophages, promoting cellular proliferation, and inducing apoptosis. Pathologic actions of angiotensin II lead to tubulointerstitial fibrosis and inflammation via a range of cytokines and chemokines including transforming growth factor (TNF)-beta1, osteopontin, tumor necrosis factor (TNF)-alpha, secreted protein acidic and rich in cysteine (SPARC), and RANTES (regulated on activation normal T-cell expression and secreted). Blockade of production of angiotensin II by an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor antagonism with an angiotensin type 1 receptor antagonist has been shown to attenuate tubulointerstitial injury and reduce expression of cytokines and matrix proteins. The role of angiotensin II in tubulointerstitial fibrosis and inflammation is addressed in this article.     

丙泊酚对大鼠机械通气相关肺损伤的保护作用及机制

目的 探讨丙泊酚对大鼠机械通气相关肺损伤影响的作用机制.方法 24只Wistar清洁级大鼠随机分为3组(n=8),采用压力控制机械通气模式通气4 h.A组为模型组,通气模式为吸气峰压(PIP)=25 cm H2O(1 cm H2O=0.098 kPa),呼气末正压(PEEP)=2 cm H2O;B、c组为同时输注丙泊酚组,通气模式同A组,B组输注模式为静注2mg/kg,继以4mg·kg-1·h-1速度持续输注;C组输注模式为5 mg/kg,继以10 mg·kg-1·h-1速度持续输注,记录基础时点、1、2、3、4 h的MAP、HR和动脉血气.4 h后处死全部大鼠,测量肺组织湿/干比(W/D),支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中总蛋白、肿瘤坏死因子α(tumor necrosis factora,TNF-α)、白介素1β(interleukin1β,IL-1β)、白介素6(interleukin6,IL-6)、白介素10(interleukin10,IL-10)和巨噬细胞炎性蛋白2(macrophage inflammatorv protein2,MIP-2)的含量,肺组织匀浆中丙二醛(malondialdehyde,MDA)和超氧化物歧化酶(superoxide dismutase,SOD)的含量,观察肺组织病理形态学变化.结果 A组MAP和PaO2在4 h时显著降低,由(116.0±7.4)mm Hg(1 mm Hg=0.133 kPa)和(379±65)mm Hg降低到(73±21)mm Hg和(103±48)mm Hg,与基础值相比差异有统计学意义(P<0.05),而B、C组与基础值相比差异无统计学意义.在4 h时A组的PaCO2显著升高(P<0.05),而B、C两组与基础值相比差异无统计学意义.肺组织湿/干比、BALF中总蛋白含量、TNF-α和MIP-2浓度A组明显高于B、C组(P<0.05),肺组织匀浆巾MDA浓度A组明显高于B、C组(P<0.05),A组SOD浓度也有所降低,但和B、C组差异无统计学意义.肺组织学病理评分B、C组也好于A组(P<0.05),B、C组间差异无统计学意义.结论 丙泊酚可减轻大鼠机械通气相关肺损伤,其机制可能与其减少炎症因子的释放,减少中性粒细胞在肺内的积聚,抑制过氧化损伤有关.     

Captopril enhances transforming growth factor (TGF)-beta1 expression in peripheral blood mononuclear cells: a mechanism independent from angiotensin converting enzyme inhibition? A study in cyclosporine-treated kidney-transplanted patients

BACKGROUND: Angiotensin (Ang) II blockade has been shown to prevent the development of renal injury in immunologically mediated diseases, but the mechanism whereby it exerts its protective effect has not been clearly defined. Transforming growth factor (TGF)-beta1 is a multifunctional cytokine with a potent immunomodulatory activity that has the potential to counteract many of the pro-inflammatory effects apparently evoked by the activation of renin-angiotensin system (RAS) in immune cells. METHODS: We set up an ex vivo and in vitro model to evaluate the effect of the angiotensin converting enzyme inhibitor (ACEi) captopril on the gene and protein expression of TGF-beta1 in human peripheral blood mononuclear cells (PBMC). RESULTS: In 20 kidney transplant recipients chronically treated with cyclosporine (CsA), 1-month treatment with captopril increased TGF-beta mRNA by 120% and TGF-beta1 protein release by 140% upon stimulation of PBMC with phytohemagglutinin (PHA) and phorbol myristate acetate (PMA) ( P<0.01). PBMC from healthy controls, when exposed in vitro to 5 microM captopril, showed a significant increase of TGF-beta1 release, whereas the ACEi enalapril failed to modify the expression of the cytokine. Ang II (100 pM) strongly inhibited TGF-beta1 synthesis by PBMC, and such effect was completely abolished by the addition of 200 ng/mL CsA, as well as by 1 micrpM losartan. Thus, captopril enhances TGF-beta1 gene and protein expression by PBMC by way of a mechanism independent, at least in part, from ACE inhibition, while CsA abrogates the inhibition of TGF-beta1 expression induced by Ang II. CONCLUSION: Collectively, these findings support the utility of combined treatment with captopril and CsA in the multitherapeutic management of organ transplant and, possibly, a strategy to decrease the dose of the calcineurin inhibitor in kidney-transplant recipients.     

Temporary losartan or captopril in young SHR induces malignant hypertension despite initial normotension

BACKGROUND: Exposure of normotensive rats to angiotensin-converting enzyme (ACE) inhibitors in early life causes hypertrophy of intrarenal arteries. Similar defects have been found in knockout mice lacking angiotensinogen, ACE, or angiotensin II type 1 (AT1) receptors. On the other hand, transient inhibition of the renin-angiotensin system from 2 weeks of age in spontaneously hypertensive rats (SHR), either with ACE inhibitors or with AT1 receptor antagonists partially prevents the increase in blood pressure. However, permanent treatment of SHR from conception onwards with ACE inhibitors completely prevents hypertension. Although these studies demonstrated protection from hypertension-induced changes in the heart and large arteries, renal arteries were not studied and follow-up did not extend beyond 6 months of age. We postulated that while brief exposure to ACE inhibitors or AT1 receptor antagonists in young SHR would temporarily decrease blood pressure, it would also be associated with development of intrarenal arterial malformation, and ultimately have deleterious effects. METHODS: Direct effects on intrarenal arterial morphology of an ACE inhibitor (captopril, 100 mg/kg/day) and an AT1 receptor antagonist (losartan, 50 mg/kg/day), administered from the last week of gestation until 8 weeks of age were examined in SHR. After stopping treatment at 8 weeks, we continued to monitor blood pressure until spontaneous death. RESULTS: Systolic blood pressure at 8 weeks was normalized by captopril and losartan (SHR control 187 +/- 8 mm Hg; captopril 118 +/- 5 mm Hg; and losartan 120 +/- 9 mm Hg). However, by 30 weeks, blood pressure had increased to control SHR levels. At 4 weeks, the media of renal arteries and arterioles was hypertrophied. Marked smooth muscle cell hyperplasia of cortical arteries resulted in significantly increased wall thickness by 8 weeks, despite similar external diameter. Arterial wall structure was disrupted, with fragmentation of elastic fibers and irregular distribution of collagen type I fibers. After stopping treatment, the rats gradually began to show poor health and all had died by 1 year of age, while all 1-year-old control SHR females were in good health. The cause of morbidity and mortality in the rats treated in early life was clearly malignant hypertension. Severe hypertrophy of renal arterioles was found, as well as cerebral hemorrhage. CONCLUSION: Despite initial normalization of blood pressure interference with the renin-angiotensin system during a crucial stage of development in SHR can initiate marked smooth muscle cell hyperplasia and disruption of the wall structure of the intrarenal arteries. Subsequent progression of this intrarenal process after cessation of treatment suggests an independent process that eventually results in malignant hypertension and early death.     

ACE and non-ACE pathways in the renal vascular response to RAS interruption in type 1 diabetes mellitus

BACKGROUND: The enormous contribution of renin-angiotensin system (RAS) interruption with ACE (angiotensin-converting enzyme) inhibitors and angiotensin II receptor blockers (ARB) in the treatment of diabetic nephropathy has led to interest in the factors involved in angiotensin II (Ang II) generation. In normal subjects, RAS interruption using an ARB produced a 50% greater renal plasma flow (RPF) rise than with an ACE inhibitor, suggesting a substantial contribution of non-ACE pathways. Moreover, immunohistochemistry studies in kidneys of overtly proteinuric diabetic subjects showed up-regulation of chymase, an alternative Ang II-generating enzyme. Our aim was to determine the degree to which the non-ACE pathways contribute to RAS activation in type 1 diabetes mellitus (DM). METHODS: Type 1 DM patients (N= 37, 14 M/23 F; age 31 +/- 2 years; DM duration 16 +/- 1.7 years; HbA1c 7.7.0 +/- 0.3%) were studied on a high-salt diet. They received captopril 25 mg po one day and candesartan 16 mg po the next day. RPF and glomerular filtration rate (GFR) were measured before and up to 4 hours after drug administration. RESULTS: Both captopril and candesartan induced a significant rise in RPF (baseline vs. peak <0.0001 for both), and the rise was concordant for the 2 drugs (r= 0.77, P < 0.001). However, the RPF responses were not significantly different between the 2 drugs (captopril 72 +/- 11 mL/min/1.73 m(2), candesartan 75 +/- 12, P= 0.841). CONCLUSION: In predominantly normoalbuminuric, normotensive type 1 DM, activation of the intrarenal RAS reflects a mechanism involving primarily the classic ACE pathway.     

Hypercholesterolemia in rats induces podocyte stress and decreases renal cortical nitric oxide synthesis via an angiotensin II type 1 receptor-sensitive mechanism

Podocyte stress precedes proteinuria in hypercholesterolemic rats. Molsidomine, a nitric oxide (NO) donor, prevented podocyte stress and proteinuria in long-term hypercholesterolemia, suggesting that podocyte stress was due to NO deficiency. Podocytes express the angiotensin II type 1 receptor, which influences their function. Because NO counteracts angiotensin II, it was hypothesized that in a setting of impaired renal NO availability, angiotensin II receptor inhibition could prevent podocyte stress. For determining the effect of NO deficiency on podocyte stress, one group of female rats were fed 2% cholesterol and another group the arginine analogue N-omega-nitro-L-arginine (L-NNA; 40 mg/kg food) for 2 wk. Another group of rats that were fed 2% cholesterol also received the NO donor molsidomine (120 mg/L water) for 2 wk before and during cholesterol feeding. For determining the influence of angiotensin II in the setting of decreased renal NO availability, rats that were treated with cholesterol or L-NNA received the angiotensin II type 1 antagonist losartan (200 mg/L water) for 2 wk before and during cholesterol or L-NNA administration. Desmin staining and electron microscopy were used to monitor podocyte activation. Glomerular caveolin was quantified by immunohistochemistry. Renal cortical NO synthesis, NO synthase isoforms, and caveolin-1 protein mass were also measured. Both short-term cholesterol and L-NNA induced podocyte stress as evidenced by enhanced desmin staining and electron-dense fused foot processes. Podocyte stress was prevented by molsidomine in short-term hypercholesterolemia. Furthermore, losartan prevented podocyte stress in rats that were treated with cholesterol or with L-NNA. Finally, hypercholesterolemia decreased renal cortical NO synthase activity and increased caveolin-1 protein mass and glomerular caveolin staining, and these changes were also prevented by losartan. It is suggested that podocyte stress in these models of early injury results from angiotensin II, unopposed by the action of endogenous NO. This underscores the strategic role of angiotensin II blockers in early kidney disease.     

Divergent regulation of circulating and intrarenal renin-angiotensin systems in response to long-term blockade

BACKGROUND/AIMS: Long-term treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin (Ang) II type I (AT(1)) receptor blockers can improve kidney function and attenuate the progressive decline in kidney function associated with age. In this study in Wistar rats medicated for 22 months, we determined the effects of enalapril (10 mg/kg/day) and losartan (30 mg/kg/day) treatment, in comparison with vehicle (tap water), on renal AngII receptor density and circulating and urinary components of the renin-angiotensin system (RAS). METHODS: Kidney sections were incubated with [(125)I-sarcosine(1)-threonine(8)]AngII (0.6 nM) for Ang receptor density, and Ang peptides were determined using radioimmunoassays. RESULTS: Receptor density was approximately 50% higher in vasa recta, glomeruli, and tubulointerstitium in enalapril-treated rats and lower in vasa recta and glomeruli in losartan-treated relative to vehicle-treated rats. Losartan and enalapril treatment elevated plasma levels of AngI and Ang-(1-7) while AngII increased only in losartan-treated rats. In contrast, both treatments were associated with a reduction in urinary excretion of all three Ang peptides as compared with control rats. CONCLUSION: The reduction in urinary Ang peptides with losartan and enalapril treatment suggests that blockade of intrarenal AngII may be an important mechanism underlying the renoprotection seen with such treatments.     

大鼠呼吸机相关肺损伤热休克蛋白70和核因子-κB的表达及其意义

目的 探讨呼吸机所致肺损伤(VILI)炎症反应中热休克蛋白70(HSP70)和核因子-κB(NF-κB)表达的意义.方法 健康SD大鼠30只,实施麻醉和气管切开术后分别接受不同潮气量(VT)的通气(通气时间均为4 h).随机分为以下3组:对照组(A组);常规通气组(B组,VT=10ml/kg);损伤通气组(C组,VT=40ml/kg).4 h后放血处死动物,测定肺湿/干比重、髓过氧化物酶(MPO)活性及肺泡灌洗液(BALF)中总蛋白含量,光镜下行白细胞(WBC)计数;Western blot检测肺组织HSP70及NF-κB的表达.结果 在大潮气量机械通气4 h后,BALF中总蛋白含量、肺湿干比、WBC计数和MPO水平(3.89±0.31、5.83±0.42、6.10±0.80、7.31±1.21)均明显更高(P＜0.05);肺组织中HSP70、NF-κB表达水平(1.36±0.13、0.41±0.07)均显著增加,且两者呈负相关.结论 HSP70可通过抑制NF-κB的活性,保护肺组织避免VILI.     

不同机械通气方式对外源性肺表面活性物质治疗大鼠呼吸机相关性肺损伤效果的影响

目的 探讨不同机械通气方式对外源性肺表面活性物质(PS)治疗大鼠呼吸机相关性肺损伤(VILI)效果的影响.方法 雄性Wistar大鼠42只,体重310～356 g,随机分为6组(n=7):CVT6组、SVT6组、CVT10组、SVT10组、CVT14组和SVT14组.VT分别为6、10、14 ml/kg,通气频率分别为75、45、32次/min.采用高气道压机械通气(HPV,气道峰压为40 cm H20,PEEP为0)制备大鼠VILI模型.于HPv前(T0,基础值)及通气15～25 min,在呼气末经气道注入4 ml/kg空气,测定气道压力,计算胸肺顺应性,当其降至基础值50%时,PEEP升高至7.5 cm H2O.吸除气道内水肿液后,SVT6组、SVT10组和SVT14组给予PS 100 mg/kg,CVT6组、CVT10组和CVT14组给予等容量空气,并按不同VT和通气频率行机械通气.于T0、HPV后5 min(T1)、给予PS后15、30、60、90及120 min(T2-6)时测定MAP,采集股动脉血样行血气分析,于T1,6时收集气道内水肿液,于T6时处死大鼠取肺组织,观察病理学结果.结果 相同机械通气方式下,给予Ps后大鼠呼吸机相关性肺损伤较对照组减轻;不同机械通气方式下,SVT10组大鼠呼吸机相关性肺损伤较其余组均减轻.SVT10组肺组织病理损伤较其余组减轻.结论 采用VT10 ml/kg、通气频率45次/min行机械通气时PS治疗大鼠VILI的效果较好.     

Angiotensin II formation in the kidney and nephrosclerosis in Ren-2 hypertensive rats.

BACKGROUND: Ren-2 transgenic hypertensive rats develop malignant hypertensive nephrosclerosis despite low to normal plasma angiotensin II and suppressed renal renin. We tested the hypothesis that local angiotensin II formation occurs at sites of renal vascular and interstitial injury in this model. METHODS: Heterozygous Ren-2 transgenic rats were compared with normotensive Sprague-Dawley-Hannover control rats and Ren-2 transgenic rats treated with a very low dose of an angiotensin II type 1 (AT1) receptor antagonist, 1 mg/kg/day losartan, for 4 weeks. Blood pressure measurements, quantifications of urinary albumin, plasma and tissue angiotensin II as well as immunohistochemical analyses were performed. RESULTS: Systolic blood pressure was not affected by losartan during the study but intra-arterial recordings revealed a decrease of blood pressure. Losartan reduced albumin excretion, cell proliferation, macrophage influx, collagen I and collagen IV deposition. Plasma angiotensin II was decreased, while kidney tissue angiotensin II content was increased in Ren-2 transgenic rats compared with control rats. In Ren-2 transgenic rats, juxtaglomerular renin and angiotensin II staining were reduced, but there was a marked angiotensin II staining at foci of tubulo-interstitial fibrosis and at proliferative malignant vascular lesions. CONCLUSION: We conclude that local angiotensin II formation is increased in proliferative or fibrotic kidney lesions in the Ren-2 transgenic rat. Local angiotensin II formation may help to explain why the AT1 receptor antagonist prevents or ameliorates this transgenic model of malignant nephrosclerosis despite low to normal plasma angiotensin II and suppressed renal renin.     

Comparison of the effects of quinapril and losartan on carotid artery intima-media thickness in patients with mild-to-moderate arterial hypertension

BACKGROUND: Ultrasonographic evidence of increased carotid intima-media thickness (IMT) is known to be associated with generalized atherosclerosis. Therapeutic blockade of the renin-angiotensin system (RAS) with angiotensin-converting enzyme (ACE) inhibitors reportedly reduces carotid IMT in humans. However, there has been no head-to-head comparison of the effects of ACE inhibitor and angiotensin receptor blocker (ARB), a newer type of RAS inhibitor, on carotid IMT. METHODS: 57 hypertensive patients were randomly assigned to treatment with one of two antihypertensive drugs: ACE inhibitor (quinapril; n = 25, group Q) or ARB (losartan; n = 18, group L). RESULTS: After 1 year of treatment, a similar decrease in mean blood pressure was observed in all groups. Carotid IMT was decreased significantly in group Q (10% decrease, p < 0.05) but did not change in group L. There were no significant changes in other atherosclerotic factors between these two groups. Conclusion: Our findings suggest that the antiatherosclerotic effect of quinapril is more potent than that of losartan in hypertensive patients. This effect appears unrelated to the drug's antihypertensive action or to traditional atherosclerotic factors.     

Regional gas exchange and cellular metabolic activity in ventilator-induced lung injury

BACKGROUND: Alveolar overdistension and repetitive derecruitment-recruitment contribute to ventilator-induced lung injury (VILI). The authors investigated (1) whether inflammatory cell activation due to VILI was assessable by positron emission tomography and (2) whether cell activation due to dynamic overdistension alone was detectable when other manifestations of VILI were not yet evident. METHODS: The authors assessed cellular metabolic activity with [(18)F]fluorodeoxyglucose and regional gas exchange with [(13)N]nitrogen. In 12 sheep, the left ("test") lung was overdistended with end-inspiratory pressure of 50 cm H(2)O for 90 min, while end-expiratory derecruitment of this lung was either promoted with end-expiratory pressure of -10 cm H(2)O in 6 of these sheep (negative end-expiratory pressure [NEEP] group) or prevented with +10 cm H(2)O in the other 6 (positive end-expiratory pressure [PEEP] group) to isolate the effect of overdistension. The right ("control") lung was protected from VILI. RESULTS: Aeration decreased and shunt fraction increased in the test lung of the NEEP group. [(18)F]fluorodeoxyglucose uptake of this lung was higher than that of the control lung and of the test lung of the PEEP group, and correlated with neutrophil count. When normalized by tissue fraction to account for increased aeration of the test lung in the PEEP group, [(18)F]fluorodeoxyglucose uptake was elevated also in this group, despite the fact that gas exchange had not yet deteriorated after 90 min of overdistension alone. CONCLUSION: The authors could detect regional neutrophil activation in VILI even when end-expiratory derecruitment was prevented and impairment of gas exchange was not evident. Concomitant end-expiratory derecruitment converted this activation into profound inflammation with decreased aeration and regional shunting.     

Role of angiotensin and endothelin in testicular ischemia reperfusion injury

Objectives: To determine whether angiotensin and endothelin have any role in testicular ischemia reperfusion injury by investigating the effects of the angiotensin converting enzyme inhibitor enalapril, selective non‐peptide angiotensin‐II type I blocker losartan and dual endothelin receptor blocker bosentan. Methods: Rats were anesthetized with thiopental sodium (50 mg/kg i.p.) before the operation. The left testicular artery and vein of rats were occluded for 1 h; before the bilateral orchiectomy, the organ was allowed to reperfuse for 3 h or 24 h. Enalapril (20 mg/kg i.p.), losartan (30 mg/kg i.p.), bosentan (10 mg/kg i.p.) or vehicle (saline) were given 30 min before reperfusion. Malondialdehyde level was measured in testicular tissue after 3 h of reperfusion. Histological examination was carried out after 24 h of reperfusion. Results: Ischemia reperfusion caused a significant increase in malondialdehyde level of ipsilateral testis, and histopathological injury in both ipsilateral and contralateral testes. Enalapril, losartan and bosentan treatments prevented the ischemia reperfusion‐induced augmentation in malondialdehyde levels. Only bosentan treatment ameloriated ischemia reperfusion‐induced histopathological alterations. Conclusions: Endothelin might play a more important role in pathogenesis of testicular ischemia reperfusion injury when compared with angiotensin.     

Role of the renin angiotensin system in diabetic nephropathy

Diabetic nephropathy has been the cause of lot of morbidity and mortality in the diabetic population. The renin angiotensin system (RAS) is considered to be involved in most of the pathological processes that result in diabetic nephropathy. This system has various subsystems which contribute to the disease pathology. One of these involves angiotensin II (Ang II) which shows increased activity during diabetic nephropathy. This causes hypertrophy of various renal cells and has a pressor effect on arteriolar smooth muscle resulting in increased vascular pressure. Ang II also induces inflammation, apoptosis, cell growth, migration and differentiation. Monocyte chemoattractant protein-1 production responsible for renal fibrosis is also regulated by RAS. Polymorphism of angiotensin converting enzyme (ACE) and Angiotensinogen has been shown to have effects on RAS. Available treatment modalities have proven effective in controlling the progression of nephropathy. Various drugs (based on antagonism of RAS) are currently in the market and others are still under trial. Amongst the approved drugs, ACE inhibitors and angiotensin receptor blockers (ARBs) are widely used in clinical practice. ARBs are shown to be superior to ACE inhibitors in terms of reducing proteinuria but the combined role of ARBs with ACE inhibitors in diabetic nephropathy is under debate.     

老年患者呼吸机相关性肺损伤及全麻术中保护性肺通气策略的应用

机械通气可造成呼吸机引起的肺损伤(ventilator-induced lung injury,VILI),由于老年患者常合并呼吸功能减退,所以全麻期间更易引起VILI,现就全身麻醉下老年患者机械通气引起的肺损伤的发生机制以及相关保护性肺通气策略及应用的研究进展作一综述.