Mechanisms involved in the relaxant action of testosterone in the renal artery from male normoglycemic and diabetic rabbits

Kidney disease is a frequent complication in diabetes, and significant differences have been reported between male and female patients. Our working hypothesis was that diabetes might modify the vascular actions of testosterone in isolated rabbit renal arteries and the mechanisms involved in these actions. Testosterone (10^?8 to 10^?4 M) induced relaxation of precontracted arteries, without significant differences between control and diabetic rabbits. Both in control and diabetic rabbits endothelium removal inhibited testosterone relaxant action. In arteries with endothelium, incubation with indomethacin (10^?5 M), N^G-nitro-l-arginine (10^?5 M) or tetraethylammonium (10^?5 M) did not modify relaxations to testosterone neither in control nor in diabetic rabbits. In endothelium-denuded arteries indomethacin enhanced the relaxant action of testosterone, both in control and diabetic rabbits. In arteries from diabetic rabbits, eNOS, iNOS and COX-1 expression and testosterone-induced release of thromboxane A₂ and prostacyclin were not significantly different from those observed in control rabbits. However, COX-2 expression was significantly lower in diabetic rabbits that in control rabbits. In nominally Ca²⁺-free medium, cumulative addition of CaCl₂ (10^?5 to 3 × 10^?2 M) contracted previously depolarized arteries. Testosterone (10^?4 M) inhibited CaCl₂ contractions of the renal artery both in control and diabetic rabbits. These results show that testosterone relaxes the renal artery both in control and diabetic rabbits. This relaxation is modulated by muscular thromboxane A₂, it is partially mediated by endothelial prostacyclin, and it involves the blocking of extracellular Ca²⁺ entry. Diabetes does not modify the mechanisms involved in the relaxant action of testosterone in the rabbit renal artery.     

The vasorelaxant effect of gallic acid involves endothelium-dependent and -independent mechanisms

The mechanisms of action involved in the vasorelaxant effect of gallic acid (GA) were examined in the isolated rat thoracic aorta. GA exerted a relaxant effect in the highest concentrations (0.4–10 mM) in both endothelium-intact and endothelium-denuded aortic rings. Pre-incubation with L-NAME, ODQ, calmidazolium, TEA, 4-aminopyridine, and barium chloride significantly reduced the pEC₅₀ values. Moreover, this effect was not modified by indomethacin, wortmannin, PP2, glibenclamide, or paxillin. Pre-incubation of GA (1, 3, and 10 mM) in a Ca^2 +-free Krebs solution attenuated CaCl₂-induced contractions and blocked BAY K8644-induced vascular contractions, but it did not inhibit a contraction induced by the release of Ca^2 + from the sarcoplasmatic reticulum stores. In addition, a Western blot analysis showed that GA induces phosphorylation of eNOS in rat thoracic aorta. These results suggest that GA induces relaxation in rat aortic rings through an endothelium-dependent pathway, resulting in eNOS phosphorylation and opening potassium channels. Additionally, the relaxant effect by an endothelium-independent pathway involves the blockade of the Ca^2 + influx via L-type Ca^2 + channels.     

Post receptor determinants of acute platelet response to clopidogrel in patients with symptomatic myocardial ischemia

BackgroundClopidogrel resistance is more common in patients with loss-of-function CYP2C19 genotypes. Since adenylate cyclase (AC) and soluble guanylate cyclase (sGC) pathways are variably impaired in patients with ischaemic heart disease, we tested the relevance of these determinants in patients undergoing acute loading with clopidogrel (600 mg) prior to non-emergent coronary stenting.MethodsInhibitory effects of prostaglandin E₁ (PGE₁, an AC activator) and sodium nitroprusside (NP, a sGC activator) on platelet aggregation were determined at baseline and compared with platelet responses to clopidogrel (4 h after administration) assessed as ∆ADP, and Platelet Reactivity Index (∆PRI). Data were analysed according to CYP2C19 genotype.ResultsIn patients without loss of function mutations (n = 18), ∆ADP but not ∆PRI, was directly correlated with baseline PGE₁ responsiveness (r_s = 0.62, p = 0.005)). NP responsiveness did not predict ∆ADP. However there was no relationship between clopidogrel responses and either PGE₁ or NP responsiveness in patients with loss of function mutations. Multivariate correlates of clopidogrel response were both the genotype status (β = −0.609, p < 0.001) and the baseline response to PGE₁ (β = 0.303, p = 0.03).ConclusionsWhile genetically impaired bio-activation markedly limits acute (4 h) clopidogrel response, impaired AC signalling provides an additional cause for clopidogrel resistance.     

Frontal systems deficits in stimulant-dependent patients: Evidence of pre-illness dysfunction and relationship to treatment response

BackgroundFrontal systems dysfunction is present in stimulant-dependent patients. However, it is unclear whether this dysfunction is a pre-morbid risk factor or stimulant-induced, is severe enough to be clinically relevant, and if it is relevant to treatment response. These questions were addressed using the Frontal Systems Behavior Scale (FrSBe), a reliable and valid self-report assessment of three neurobehavioral domains associated with frontal systems functioning (Apathy, Disinhibition, and Executive Dysfunction, summed for a Total), that assesses both pre- and post-morbid functioning, and has a specific cutoff for defining clinically significant abnormalities.MethodSix sites evaluating 12-step facilitation for stimulant abusers obtained the FrSBe from 180 methamphetamine- and/or cocaine-dependent participants. Dichotomous treatment response measures included self-reported stimulant use, stimulant urine drug screens, and treatment completion.ResultsA substantial percentage of participants retrospectively reported clinically significant neurobehavioral abnormalities prior to lifetime stimulant abuse initiation (e.g., 67.5% on FrSBe-Total) with a significant increase in the proportion reporting such abnormalities for current functioning (86% on FrSBe-Total; p < 0.0001). Treatment response was significantly worse for participants with, relative to those without, clinically significant Disinhibition as measured by treatment non-completion (31.6% vs. 15.6%, OR = 2.51) and self-reported stimulant use during treatment (40.5% vs. 16.7%, OR = 3.40).ConclusionThese findings suggest that frontal systems dysfunction is present prior to stimulant-abuse onset and worsens with stimulant use. Disinhibition may be a prime target for intervention in stimulant-dependent individuals.     

EP3 receptor-mediated contraction of human pulmonary arteries and inhibition of neurogenic tachycardia in pithed rats

BackgroundThe aim of our study was (1) the pharmacological characterization of EP₃ receptors in human pulmonary arteries and (2) the examination of the potential involvement of these receptors in the regulation of neurogenic tachycardia in pithed rats. L-826266 served as the EP3 receptor antagonist.MethodsExperiments were performed on isolated human pulmonary arteries and pithed rats.ResultsThe prostanoid EP₁/EP₃ receptor agonist sulprostone (1 nM – 100 μM) concentration-dependently contracted isolated human pulmonary arteries (pEC₅₀, 6.88 ± 0.10). The EP₁ receptor antagonist SC 19920 (100 μM) did not affect the vasoconstriction induced by sulprostone, the TP receptor antagonist sulotroban (10 μM) only slightly attenuated the effects elicited by sulprostone > 3 μM, whereas L-826266 (10 μM) shifted its concentration-response curve to the right (apparent pA₂ value 6.18; incubation time 0.5 h). In rings exposed to L-826266 (0.1,1 or 10 μM) for 3 h, a concentration-dependent inhibitory effect against the sulprostone-induced vasoconstriction was obtained, yielding a Schild plot-based pA₂ value of 7.39. In pithed rats, sulprostone (10 – 1,000 nmol/kg), but not the IP/EP₁ receptor agonist iloprost (1-100 nmol/kg), inhibited the electrically evoked increase in heart rate (HR) dosedependently, maximally by at least 80%. L-826266 (3 μmol/kg) did not affect basal HR and diastolic blood pressure, but reduced the inhibitory effect of sulprostone 1,000 nmol/kg by about 20%.ConclusionEP₃ receptors (1) located postsynaptically strongly contract human pulmonary arteries and (2) located presynaptically on sympathetic nerve fibers supplying the heart of pithed rats strongly inhibit the neurogenic tachycardia.     

Development of an alternative non-obese non-genetic rat model of type 2 diabetes using caffeine and streptozotocin

BackgroundThe aim of the present study was to develop an alternative non-obese non-genetic rat model of type 2 diabetes (T2D).MethodsSix-week-old male SD rats were randomly divided into six groups, namely: Normal Control (NC), Diabetic Control (DBC), Caffeine 5 mg/kg BW + STZ (CAF5), Caffeine 10 mg/kg BW + STZ (CAF10), Caffeine 20 mg/kg BW + STZ (CAF20) and Caffeine 40 mg/kg BW + STZ (CAF40) and were fed a normal rat pellet diet and drinking water ad libitum throughout the experimental period. After a one week acclimatization period, diabetes was induced in the animals in DBC and all CAF groups with an injection (i.p.) of the respective dosages of caffeine (mg/kg BW) 15 min before the injection of STZ (65 mg/kg BW) when normal saline was injected to the DBC group instead of caffeine. The NC group received normal saline and buffer instead of caffeine and STZ, respectively. One week after the STZ injection, animals with non-fasting blood glucose > 300 mg/dl were considered as diabetic. Three weeks after the STZ injection, the animals in the CAF5 and CAF10 groups were eliminated from the study due to the severity of diabetes and the experiment was continued with the remainder groups for a 13 weeks period.Results and conclusionThe data of food and fluid intake, body weight, blood glucose, glucose tolerance test, HOMA-IR, HOMA-beta, serum insulin, fructosamine, lipid profile and organ specific enzymes, anti-diabetic drug response tests, and pancreatic histopathology suggest that CAF20 group can be a better alternative non-genetic model of non-obese T2D.     

Role of NO-synthases and cyclooxygenases in the hyperreactivity of male rabbit carotid artery to testosterone under experimental diabetes

Cardiovascular disease is the major cause of morbidity and mortality in diabetic patients, which in turn is also associated with low levels of serum testosterone. The working hypothesis was that diabetes might modify the mechanisms involved in the vascular actions of testosterone in isolated rabbit carotid arteries. Testosterone (10^?8–3 × 10^?4 M) induced a concentration-dependent relaxation of precontracted carotid arteries, which was higher in diabetic than in control rabbits. In control rabbits neither endothelium removal nor the nitric oxide synthase (NOS) inhibitor N^G-nitro-l-arginine (l-NOArg, 10^?5 M) modified the relaxant action of testosterone, and the cyclooxygenase (COX) inhibitor indomethacin (10^?5 M) enhanced this relaxation. In contrast, in diabetic rabbits endothelium removal, l-NOArg (10^?5 M) or indomethacin (10^?5 M) inhibited the testosterone induced relaxation. In arteries from diabetic rabbits, eNOS, iNOS and COX-2 expression and testosterone induced release of prostacyclin resulted enhanced in comparison with arteries from control rabbits. Testosterone (10^?4 M) strongly inhibited CaCl₂ (10^?5–3 × 10^?2 M) concentration-related contractions of the carotid artery both in control and diabetic rabbits. These results suggest that testosterone relaxes the rabbit carotid artery by blocking the extracellular calcium entry. Diabetes enhances the vasodilator response of the rabbit carotid artery to testosterone by a mechanism that at least includes an increased modulatory activity of the endothelial nitric oxide and an augmented release of COX-2 vasodilator, prostacyclin rather than the absence of COX-1 vasoconstrictor, thromboxane A₂. The hypotestosteronemia observed in diabetic rabbits could be a consequence of the increased expression of iNOS and could contribute to the hyperreactivity of the rabbit carotid artery to testosterone.     

Human urotensin II in internal mammary and radial arteries of patients undergoing coronary surgery

AimsInternal mammary (IMA) and radial artery (RA) have different incidence of vasospasm and long-term patency rates in arterial grafting. We compared the vasoreactivity of human urotensin II (hU-II) and its receptor with mechanism investigations in IMA and RA.MethodsIMA and RA taken from patients undergoing coronary bypass surgery were studied in organ baths. Urotensin receptor expression was determined by RT-PCR.ResultshU-II contracted IMA with pD₂ of 8.57 ± 0.41 and 45.4 ± 9.1% E_max of contraction to 100 mM KCl, whereas caused less contractile responses in RA (pD₂:8.30 ± 0.79, E_max:20.4 ± 4.8%, p < 0.05). Nifedipine inhibited hU-II-contraction in IMA. In U₄₆₆₁₉-precontraction, hU-II elicited comparable relaxation in IMA (pD₂:8.39 ± 0.43, E_max:56.1 ± 4.0%) and RA (pD₂:9.03 ± 0.46, E_max:65.2 ± 7.1%). The relaxation was abolished by endothelium denudation and by indomethacin, oxadiazoloquinoxalinone or N^ω-nitro-l-arginine, oxyhemoglobin, and Ca²⁺-activated K⁺ channel (K_Ca) blockers. Urotensin receptor mRNA was detected in both arteries.ConclusionshU-II is an important spasmogen in arterial grafts with receptors expressed in IMA and RA. hU-II elicits stronger contraction in IMA than in RA and a moderate endothelium-dependent relaxation attributable to nitric oxide, prostacyclin, and endothelium-derived hyperpolarizing factor with involvement of K_Ca activation. The relaxant response of endothelium-intact IMA and RA to hU-II demonstrates the importance of preservation of endothelium in these grafts.     

Propranolol-induced relaxation in the rat basilar artery

Propranolol is a non-selective beta-adrenergic receptor blocker used in the treatment of cardiovascular diseases and migraine prophylaxis. Although it has been shown that propranolol dilates the peripheral arteries of rat, its action in the central nervous system vasculature has not been investigated. In this study, the effects of propranolol in rat basilar artery were investigated. Basilar arteries from male Wistar rats were examined in a myograph system. The relaxant effects of propranolol, pindolol, atenolol, pizotifen and methysergide were examined in basilar arteries precontracted by serotonin or PGF2α. Only propranolol and pizotifen induced vasorelaxations; the pD2 values were 5.23 ± 0.13 and 5.94 ± 0.03; respectively. The vasorelaxation induced by propranolol and pizotifen was not affected by endothelium or the presence of l-NOARG and/or indomethacin. The calcium channel blocking activity of propranolol and pizotifen was compared with that of nifedipine in a calcium free solution with high K⁺ (60 mM) concentration. These drugs shifted the concentration–response curves of calcium induced contractions with pA2 values of 5.45 ± 0.04; 7.14 ± 0.09; and 9.22 ± 0.06 respectively. The P2Y receptor agonist UTP was used to induce sustained and stable contractions in basilar artery segments. Nifedipine caused a marked, but an incomplete relaxation. Cyclopiazonic acid, an inhibitor of sarcoplasmic reticulum calcium channels, but not propranolol or pizotifen abolished the remaining tonus after partial relaxations obtained with nifedipine.These results suggest that propranolol causes vasorelaxation by blocking the L-type voltage-gated calcium channels in the rat basilar artery.     

An ounce of prevention: A pre-randomization protocol to improve retention in substance use disorder clinical trials

BackgroundMissing data in substance use disorder (SUD) research pose a significant threat to internal validity. Participants terminate involvement or become less likely to attend intervention and research visits for many reasons, which should be addressed prior to becoming problematic. During a 9-month study targeting stimulant abuse, early dropouts and participant reported attendance barriers led to implementing a structured, pre-randomization protocol with participants about retention and solution-focused strategies (the “Fireside Chat”). Our aim is to outline this approach and present data on intervention participation and research visit attendance after implementation.Methods/designSTimulant Reduction using Dosed Exercise (STRIDE) was a two-arm, multisite randomized clinical trial testing treatment-as-usual for stimulant abuse/dependence augmented by Exercise or Health Education. For both groups, study intervention visits at the site were scheduled 3/week for 12 weeks followed by 1/week for 24 weeks. During The Chat, research staff thoroughly reviewed participants' expectations, and barriers and solutions to retention. Fifteen participants were randomized (to Exercise or Health Education) prior to and fourteen were randomized after Chat implementation. Intervention and monthly follow-up attendance (before and after implementation) were compared at the site (N = 29) that developed and rigorously implemented The Chat.ResultsIndividuals who participated in The Chat (n = 14) attended significantly more intervention visits during weeks 1–12 (p < 0.001) and weeks 13–36 (p < 0.05) and attended more research visits (p < 0.001).DiscussionProactive discussion of expectations and barriers prior to randomization was associated with greater study attendance. SUD researchers should consider tailoring this approach to suit their needs. Further investigation is warranted.     

Medication adherence program: Adherence challenges and interventions in type 2 diabetes

ObjectivesTo describe medication adherence problems for adults with type 2 diabetes and to assess the nature and frequency of pharmacist activities in addressing them and proximate outcomes.DesignPre–post analysis.SettingFour community chain pharmacies located in Seattle, WA, from April 2008 to October 2009.Patients120 patients (mean age >60 years) with type 2 diabetes taking oral diabetes medications and who were 6 or more days late for refills.InterventionPharmacist telephone-initiated adherence support.Main outcomes measuresNature and frequency of adherence-related problems and intervention activities and impact on reduction in refill gaps.ResultsThe primary adherence challenge was difficulty taking medications (27.1%). Failure to remember doses and forgetting refills were reported by 24.6% and 26.3% of patients at baseline, respectively. Pharmacists provided support through some form of patient education (35.6% of encounters) or other adherence support (40.7%). Pharmacist time averaged slightly greater than 5 minutes per intervention and 12.6 ±  minutes (mean ± SD) over 12 months, with 3.4 ±  interventions per patient. Patient-specific education and adherence support by pharmacists and total intervention time were positively correlated, with a modest but significant reduction in refill gaps during 12 months of follow-up.ConclusionNot remembering to refill medications was the most commonly reported problem. Patient encounters averaged 4 to 6 minutes for the first visit and 12 to 13 minutes over 12 months. Phone calls by pharmacists to adults who were late for oral diabetes medication refills were effective in identifying adherence-related problems and developing support strategies to promote medication self-management in busy urban community chain pharmacy settings.     

Tolerance liability of diazepam is dependent on the dose used for protracted treatment

BackgroundBehavioral effects of benzodiazepines following repeated exposure vary according to the intrinsic efficacy of the benzodiazepine studied, treatment schedule and the behavioral parameters evaluated.MethodsWe applied the behavioral paradigms of spontaneous locomotor activity, elevated plus maze and grip strength to investigate the sedative, anxiolytic and myorelaxant effect of acute challenge with 2 mg/kg diazepam administered after 14 days of protracted treatment with 0.5, 2 or 10 mg/kg of diazepam. In addition, we studied the effects of everyday handling and intraperito-neal (ip) administration on animal behavior.ResultsTolerance to the sedative effect of 2 mg/kg diazepam ensued after 14 days of protracted treatment with 2 and 10 mg/kg of diazepam. In contrast, treatment with the lowest dose (0.5 mg/kg) of diazepam resulted in potentiation of the sedative effect of acute challenge with 2 mg/kg diazepam thus confounding the detection of the anxiolytic effect of diazepam. A sensitization-like response to the anxiolytic action of 2 mg/kg diazepam was seen after protracted treatment with the intermediate dose (2 mg/kg); however, anxiolytic effect was absent after protracted administration of the highest dose. Partial tolerance to the muscle relaxant effect of 2 mg/kg diazepam ensued after protracted treatment with diazepam regardless of the dose. Daily handling or ip administration did not alter the behavioral response to acute challenge with 2 mg/kg diazepam in all the three behavioral paradigms studied.ConclusionThe presented results showed that behavioral effects of acute challenge with diazepam were differently affected by the dose administered during protracted treatment.     

Perception of intoxication in a field study of the night-time economy: Blood alcohol concentration,patron characteristics,and event-level predictors

ObjectiveDetermine the relationship of subjective intoxication to blood alcohol concentration (BAC) and examine whether patron and event-level characteristics modify the relationship of BAC to subjective intoxication.MethodsAn in-situ systematic random sample of alcohol consumers attending night-time entertainment districts between 10 pm and 3 am on Friday and Saturday nights in five Australian cities completed a brief interview (n = 4628). Participants reported age, sex, and pre-drinking, energy drink, tobacco, illicit stimulant and other illicit drug use that night, and their subjective intoxication and BAC were assessed.ResultsMale and female drinkers displayed equally low sensitivity to the impact of alcohol consumption when self-assessing their intoxication (BAC only explained 19% of variance). The marginal effect of BAC was not constant. At low BAC, participants were somewhat sensitive to increases in alcohol consumption, but at higher BAC levels that modest sensitivity dissipated (actual BAC had less impact on self-assessed intoxication). The slope ultimately leveled out to be non-responsive to additional alcohol intake. Staying out late, pre-drinking, and being young introduced biases resulting in higher self-assessed intoxication regardless of actual BAC. Further, both energy drinks and stimulant use modified the association between BAC and perceived intoxication, resulting in more compressed changes in self-assessment as BAC varies up or down, indicating less ability to perceive differences in BAC level.ConclusionsThe ability of intoxicated patrons to detect further intoxication is impaired. Co-consumption of energy drinks and/or stimulant drugs is associated with impaired intoxication judgment, creating an additional challenge for the responsible service and consumption of alcohol.     

Estrogens are needed for the improvement in endothelium-mediated dilation induced by a chronic increase in blood flow in rat mesenteric arteries

Resistance arteries play a key role in the control of local blood flow. They undergo outward remodeling in response to a chronic increase in blood flow as seen in collateral artery growth in ischemic disorders. We have previously shown that mesenteric artery outward remodeling depends on the endothelial estrogen receptor alpha. As outward arterial remodeling is associated with improved endothelium-dependent dilation, we hypothesized that estrogens might also play a role in flow-mediated improvement of endothelium-dependent dilation.Local increase in blood flow in first order mesenteric arteries was obtained after ligation of adjacent arteries in three-month old ovariectomized female rats treated with 17-beta-estradiol (OVX + E2) or vehicle (OVX).After 2 weeks, diameter was equivalent in high flow (HF) than in normal flow (NF) arteries with a greater wall to lumen ratio in HF vessels in OVX rats. Acetylcholine-mediated relaxation was lower in HF than in NF vessels. eNOS and caveolin-1 expression level was equivalent in HF and NF arteries.By contrast, arterial diameter was 30% greater in HF than in NF arteries and the wall to lumen ratio was not changed in OVX + E2 rats. Acetylcholine-mediated relaxation was higher in HF than in NF arteries. The expression level of eNOS was higher and that of caveolin-1 was lower in HF than in NF arteries.Acetylcholine (NO-dependent)-mediated relaxation was partly inhibited by the NO-synthesis blocker L-NAME in OVX rats whereas L-NAME blocked totally the relaxation in OVX + E2 rats. Endothelium-independent relaxation (sodium nitroprusside) was equivalent in OXV and OVX + E2 rats. Similarly, serotonin- and phenylephrine-mediated contractions were higher in HF than in NF arteries in both OVX and OVX + E2 rats in association with high ratio of phosphorylated ERK1/2 to ERK1/2.Thus, we demonstrated the essential role of endogenous E2 in flow-mediated improvement of endothelium (NO)-mediated dilatation in rat mesenteric arteries.     

Metformin raises hydrogen sulfide tissue concentrations in various mouse organs

BackgroundThe epidemic of diabetes mellitus type 2 forces to intensive work on the disease medication. Metformin, the most widely prescribed insulin sensitizer, exerts pleiotropic actions on different tissues by not fully recognized mechanisms. Hydrogen sulfide (H₂S) is involved in physiology and pathophysiology of various systems in mammals and is perceived as a potential agent in the treatment of different disorders. The interaction between biguanides and H₂S is unknown. The aim of the study is to assess the influence of metformin on the H₂S tissue concentrations in different mouse organs.MethodsAdult SJL female mice were administered intraperitoneally 100 mg/kg b.w. per day of metformin (group D1, n = 6) or 200 mg/kg b.w. per day of metformin (group D2, n = 7). The control group (n = 6) received physiological saline. The measurements of the free and acid-labile H₂S tissue concentrations were performed with Siegel spectrophotometric modified method.ResultsThere was a significant progressive increase in the H₂S concentration along with the rising metformin doses as compared to the control group in the brain (D1 by 103.6%, D2 by 113.5%), in the heart (D1 by 11.7%, D2 by 27.5%) and in the kidney (D1 by 7.1%, D2 by 9.6%). In the liver, massive H₂S accumulation was observed in the group D1 (increase by 420.4%), while in the D2 group only slight H₂S level enhancement was noted (by 12.5%).ConclusionOur experiment has shown that metformin administration is followed by H₂S tissue concentrations increase in mouse brain, heart, kidney and liver.     

Propylthiouracil modulates aortic vasculopathy in the oxidative stress model of systemic sclerosis

BackgroundIn systemic sclerosis (SSc) vasculopathy affects small arteries and capillaries, but recent evidences show also macrovascular alterations. Experimental data suggest that propylthiouracil (PTU) abrogates the development of cutaneous and pulmonary fibrosis during SSc. The aim of this study was to evaluate the effect of propylthiouracil on aortic lipid peroxidation, intima-media thickness and myofibroblasts differentiation in experimental SSc.MethodsSSc was induced in BALB/c mice by daily subcutaneous injections of hypochlorous acid (HOCl) for 6 weeks. Mice (n = 25) were randomized to receive daily: HOCl (n = 10), HOCl + PTU (n = 10), or vehicle (n = 5). Thoracic aorta was evaluated by histological methods to measure intima-media thickness and by immunostaining for α-smooth muscle actin (α-SMA) to assess myofibroblast differentiation. Aortic and plasma levels of malondialdehyde (MDA) were also measured.ResultsHOCl induced a significant increase in aortic intima-media thickness compared to controls (p < 0.001), while PTU administration prevented intima-media thickening (p < 0.01). Myofibroblast differentiation was also less evident in HOCl + PTU-treated animals (p < 0.05) compared to mice treated with HOCl alone. The increase in aortic and plasma MDA levels induced by HOCl, was significantly prevented by PTU administration (p < 0.05).ConclusionPTU, by reducing lipid peroxidation, prevents aortic thickening and myofibroblast differentiation induced by HOCl, reducing macrovascular alterations in experimental SSc.     

Reproductive toxicity of acrylamide-treated male rats

Acrylamide content is elevated in fried, baked and heat-processed starchy foods. The present experiment was conducted to investigate the reproductive toxicity of oral acrylamide in male rats. Thirty weaned SD male rats of 21-day-old were randomly allotted to three groups, and acrylamide was administered to each group at doses of 0, 5 and 10 mg/kg-d for 8 consecutive weeks. The results indicated that the growth of rats treated with acrylamide was retarded (P < 0.05), but relative weights of testes and epididymides compared to body weight were not significantly different (P > 0.05). Our results also indicate that the epididymal sperm reserves decreased significantly (P < 0.05), suggesting partial depletion of germ cells. In addition, histopathologic lesions were also present in the testes of treated rats. Furthermore, distinct expression patterns of sGC heterodimers were observed in this animal model. This may suggest different physiologic roles for sGC subunits in spermiogenesis and steroidogenesis.     

β-Glucan modulates the lipopolysaccharide-induced innate immune response in rat mammary epithelial cells

Mastitis, caused by mammary pathogenic bacteria which are frequent implications of Escherichia coli, is an important disease affecting women and dairy animals worldwide. The β-glucan binding of dectin-1 can induce its own intracellular signaling and can mediate a variety of cellular responses. This work was to investigate the effect of β-glucan on the lipopolysaccharide (LPS)-induced in?ammatory response and related innate immune signaling in primary rat mammary epithelial cells. Cells were treated with serum-free medium added with a DMSO solution containing β-glucans at concentrations of 0, 1, 5, 25 μmol/L for 12 h, and then exposed to 10 μg/mL LPS for 40 min. Moreover, cells were pretreated with BAY 11-7082 to inhibit NF-κB and then successively exposed to 5 μmol/L β-glucan, 10 μg/mL LPS, 5 μmol/L β-glucan and 10 μg/mL LPS, according to the specific experimental design. Normal control cultures contained an equal volume of DMSO, which was collected at the same time. After incubating rat mammary epithelial cells for 40 min with 10 μg/mL LPS, TLR4, MyD88 and NF-κB expression all increased (P < 0.05), as did the secretion of TNF-α and IL-1β (P < 0.05), but IκB and β-casein expression both decreased (P < 0.05). Treatment with different concentrations of β-glucan for 12 h activated Dectin1/Syk, which subsequently suppressed TLR4, MyD88 and NF-κB expression and TNF-α and IL-1β secretion. However, it restored the IκB and β-casein expression that had been induced by the 40 min incubation with 10 μg/mL LPS. Pretreatment with BAY 11-7082 at 10 µmol/L for 2 h partially prevented NF-κB induction by LPS, but the presence of β-glucan prevented this inactivation. BAY 11-7082 could not simultaneously inhibit LPS induction of TLR4, MyD88 and β-glucan activation of Dectin1/Syk in rat mammary epithelial cells. These findings demonstrated that β-glucan activation of Dectin1/Syk attenuated LPS induction of TLR4/MyD88/NF-κB and inhibited the LPS-induced inflammation factors in mammary epithelial cells, thereby providing a possibly protective effect of β-glucan in the prevention of LPS-induced dysfunction in mammary epithelial cells.     

The comparative effects of perindopril and catechin on mesangial matrix and podocytes in the streptozotocin induced diabetic rats

BackgroundHyperglycemia and advanced glucose end substance (AGE) are responsible for excessive reactive oxygen species (ROS) production, which causes oxidative stress in diabetes mellitus. Oxidative stress and high blood pressure may cause injury and glomerulosclerosis in the kidney. End-stage kidney failure induced by glomerulosclerosis leads to microalbuminuria (Ma) in diabetic nephropathy. We investigated the effects of an angiotensin converting enzyme inhibitor (ACEI), perindopril, and an antioxidant, catechin, on podocytes and the glomerular mesangial matrix in experimental diabetic nephropathy using ultrastructural visualization and immunohistochemical staining.MethodsWe compared 5 groups of male adult Wistar albino rats: a control group, an untreated diabetic group, and diabetic groups treated with perindopril, catechin, or catechin + perindopril.ResultsBlood glucose values in all diabetic groups were significantly higher than in the control group (p < 0.001). The body weight in all diabetic groups was significantly lower than in the control group (p < 0.001, p < 0.05). The kidney weight in the catechin + perindopril-treated diabetic group was significantly lower than in the untreated diabetic group (p < 0.001). In all treated diabetic groups, Ma levels decreased significantly (p < 0.001). Mesangial matrix and podocyte damage increased in the untreated diabetic group, but the group treated with catechin + perindopril showed less damage. TGF-beta 1 immunostaining was significantly lower in the catechin-treated and perindopril-treated groups than in the untreated diabetic group (p < 0.001). Catechin was more effective than ACEI in preventing podocyte structure. Podocytes appeared to be the first cells affected in diabetes mellitus. When exposed to hyperglycemia, podocytes caused the mesangial matrix to expand.ConclusionsCatechin and perindopril were more effective in preventing renal corpuscle damage when administered together.