Revisiting the action of steroids and triterpenoids on the human sperm Ca2+ channel CatSper.

The sperm-specific Ca2+ channel CatSper (cation channel of sperm) is vital for male fertility. Contradictory findings have been published on the regulation of human CatSper by the endogenous steroids estradiol, testosterone and hydrocortisone, as well as the plant triterpenoids, lupeol and pristimerin. The aim of this study was to elucidate this controversy by investigating the action of these steroids and plant triterpenoids on human CatSper using population-based Ca2+-fluorimetric measurements, the specific CatSper-inhibitor RU1968 and a functional test assessing the CatSper-dependent penetration of human sperm cells into methylcellulose. Estradiol, testosterone and hydrocortisone were found to induce Ca2+-signals in human sperm cells with EC50 values in the lower µM range. By employing the specific CatSper-inhibitor RU1968, all three steroids were shown to induce Ca2+-signals through an action on CatSper, similar to progesterone. The steroids were found to dose-dependently inhibit subsequent progesterone-induced Ca2+-signals with IC50 values in the lower µM range. Additionally, the three steroids were found to significantly increase the penetration of human sperm cells into methylcellulose, similar to the effect of progesterone. The two plant triterpenoids, lupeol and pristimerin, were unable to inhibit progesterone-induced Ca2+-signals, whereas the CatSper-inhibitor RU1968 strongly inhibited progesterone-induced Ca2+-signals. In conclusion, this study supports the claim that the steroids estradiol, testosterone and hydrocortisone act agonistically on CatSper in human sperm cells, thereby mimicking the effect of progesterone, and that lupeol and pristimerin do not act as inhibitors of human CatSper.

Neuroprotective Role of Lazaroids Against Aluminium Chloride Poisoning.

Aluminium (Al) is neurotoxic primarily because of its interference with biological enzymes in key mechanisms of metabolic pathways. Mitochondria being a major site of reactive oxygen species (ROS) production, it seems that the oxidative damage to mitochondrial proteins may underlie the pathogenesis of Al induced neurodegeneration. The present study investigates the effectiveness of the anti-oxidant property of lazaroids (U-74500A), a known lipid peroxidation inhibitor as neuroprotective agent against Al induced neurotoxicity. Al chloride was administered orally at a dose level of 100 mg/kg body wt/day in water and U-74500A was administered at a dose of 0.25 mg/kg body wt i.p. in citrate buffer for a period of 8 weeks on alternate days. Following Al exposure there was a significant increase in lipid peroxidation (LPO), ROS levels and reduction in the activity of mitochondrial complexes in all the three regions of rat brain, i.e., cerebral cortex, mid brain, and cerebellum. This decrease in the activities of electron transport complexes in turn affected the ATP synthesis and ATP levels adversely in the mitochondria. These alterations were also depicted in the histology which shows signs of hypoxia, paucity of neurons in cortical region and loosening of fibers in the white matter. U-74500A co-administration was able to restore alterations in the LPO, ROS levels as well as all the three mitochondrial complexes and caspase expression. Therefore, it is suggested that 21-aminosteroids (lazaroids), by attenuating LPO and mitochondrial dysfunction, holds a promise as an agent that can potentially reduce Al-induced adverse effects in brain.

The Acute Effect of the Antioxidant Drug U-74389G on Red Blood Cell Distribution Width Levels During Hypoxia Reoxygenation Injury in Rats.

UNLABELLED: The AIM of this experimental study was to evaluate the effect of the antioxidant drug "U-74389G" in a rat model of hypoxia reoxygenation (HR) using the previously established protocol. Effects of treatment were evaluated by mean red blood cell distribution width (RDW) levels. MATERIALS AND METHODS: 40 rats of a mean weight of 231.875 g were employed in the study. RDW levels were determined at 60 min (groups A and C) and at 120 min (groups B and D) after starting the reoxygenation. Groups A and B received no drugs, whereas rats from groups C and D were administered with U-74389G. RESULTS: demonstrated that U-74389G administration significantly decreased the RDW levels by 4.96% + 2.27% (p = 0.0175). Reoxygenation time non-significantly decreased the RDW levels by 0.27% + 2.41% (p = 0.8889). Together, U-74389G administration and reoxygenation time non-significantly decreased the RDW levels by 2.54% + 1.39% (p = 0.0679). CONCLUSIONS: U-74389G administration particulary in concert without reperfusion declines the RDW levels even within the short - time context of 1.5 hours reperfusion.

[The Effect of the Antioxidant Drug U-74389G on Magnesium Levels During Hypoxia-Reoxygenation Injury in Rats].

OBJECTIVE: The aim of this experimental study was to examine the effect of the antioxidant drug U-74389G in a rat model of hypoxia-reoxygenation using the previously established protocol. Effects of treatments were evaluated by magnesium (Mg2+) levels in blood. METHODS: Non-randomized controlled study was performed. Mg2+ levels were determined in 60 min (groups A and C) and 120 min (groups B and D) after starting the reoxygenation. Groups A and B received no drugs, whereas rats from groups C and D were administered with U-74389G. RESULTS: 40 rats 16-18 weeks old of a mean weight of 2312 g were employed in the study. It is demonstrated that U-74389G administration did not alter the Mg2+ levels (decrease in Mg2+ concentration was 0.28±2.75%; p=0.917). Reoxygenation non-significantly increased the Mg2+ levels by 4.27±2.66% (p=0.107). Together, the U-74389G administration and reoxygenation non-significantly increased the Mg2+ levels by 0.36±1.64% (p=0.823). CONCLUSION: U-74389G administration, alone or in concert with reoxygenation did not significantly affect Mg2+ level in blood after experimental hypoxia in rats.

Antioxidant 21-aminosteroid "U-74389G" ameliorates the short-time effect of hypoxia-reoxygenation on the platelet count in rats.

AIM: The aim of this experimental study was to examine the effect of the antioxidant drug "U-74389G", on rat model and particularly in a hypoxia-reoxygenation protocol. The beneficial effect or non-effectiveness of that molecule were studied hematologically using blood mean platelet count. Results were that U-74389G administration interacted or not with reoxygenation time decreased the platelet count by 6.12% ± 3.58% (p = 0.0857) and 12.83% ± 5.79% (p = 0.0303) respectively. CONCLUSIONS: U-74389G administration interacted or not with reoxygenation time decreases the platelet count within short-term time of 2 hours by different significance levels.

The effect of U-74389G on pancreas ischemia-reperfusion injury in a swine model.

BACKGROUND: Oxidative stress is a crucial factor in the pathophysiology of acute pancreatitis and its systemic complications. Lazaroids are a novel class of antioxidants that potently protect pancreatic acinar cells against oxidant attack. The aim of our study was to evaluate the therapeutic potential of 21-aminosteroid U-74389G in pancreatic injury after ischemia and reperfusion of the organ in a swine model. MATERIALS AND METHODS: Twelve pigs (weighing 28-35 kg) were randomized into the following two experimental groups: group A (control group, n = 6): ischemia of pancreas (30 min) followed by reperfusion for 120 min; and group B (n = 6): ischemia of pancreas (30 min), U-74389G intravenous injection (10 mg/kg) in the inferior vena cava, and reperfusion for 120 min. Tissue and blood sampling was conducted at 0, 30, 60, 90 and 120 min after reperfusion. Repeated measures analysis of variance was performed for the evaluation of differences between the two groups. RESULTS: Histopathologic evaluation did not reveal a statistically significant difference concerning hemorrhage (P = 0.193), leukocyte infiltration (P = 0.838), acinar necrosis (P = 0.183), and vacuolization (P = 0.185) in the pancreatic tissue between the two groups; nevertheless, edema seemed to be more pronounced in the U-74389G group (P = 0.020). Serum metabolic data in the control and therapy groups were not significantly different; accordingly, tissue malondialdehyde levels (P = 0.705) and tumor necrosis factor α values (P = 0.863) did not differ between the two groups. CONCLUSIONS: On the basis of the histologic data and the absence of reduction in the malondialdehyde and tumor necrosis factor α levels, it is concluded that the administration of U-74389G does not seem to exert a sizable therapeutic effect in attenuating pancreatic damage from ischemia-reperfusion injury.

Modulation of crucial adenosinetriphosphatase activities due to U-74389G administration in a porcine model of intracerebral hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) represents a partially-understood cerebrovascular disease of high incidence, morbidity and mortality. We, herein, report the findings of our study concerning the role of two important adenosinetriphosphatases (ATPases) in a porcine model of spontaneous ICH that we have recently developed (by following recent references as well as previously-established models and techniques), with a focus on the first 4 and 24 h following the lesion's induction, in combination with a study of the effectiveness of the lazaroid antioxidant U-74389G administration. Our study demonstrates that the examined ICH model does not cause a decrease in Na(+),K(+)-ATPase activity (the levels of which are responsible for a very large part of neuronal energy expenditure) in the perihematomal basal ganglia territory, nor a change in the activity of Mg(2+)-ATPase. This is the first report focusing on these crucial ATPases in the experimental setting of ICH and differs from the majority of the findings concerning the behavior of these (crucial for central nervous system cell survival) enzymes under stroke-related ischemic conditions. The administration of U-74389G (an established antioxidant) in this ICH model revealed an injury specific type of behavior, that could be considered as neuroprotective provided that one considers that Na(+),K(+)- and Mg(2+)-ATPase inhibition might in this case diminish the local ATP consumption.

Bioactive pregnane steroids from a South China Sea gorgonian Carijoa sp.

A new pregnane steroid, 1, and three known analogues 2-4, have been isolated from a gorgonian Carijoa sp. collected from the South China Sea. The planar structure and relative configuration of 1 were elucidated from comprehensive spectroscopic data. Its absolute configuration was determined by application of the modified Mosher method. Compounds 1, 3 and 4 exhibited cytotoxicity against the human hepatoma cell line Bel-7402, with IC50 values of 9.33, 11.02 and 18.68 µM, respectively. Additionally, compound 1 exhibited promising antibacterial activity against Pseudomona puido, with a MIC value of 31 nM, which is approximately 5-fold more potent than ciprofloxacin (MIC = 156 nM).

Activation of acetylcholinesterase after U-74389G administration in a porcine model of intracerebral hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes. Despite high incidence, morbidity and mortality, the precise pathophysiology of spontaneous ICH is not fully understood, while there is little data concerning the mechanisms that follow the primary insult of the hematoma formation. The cholinergic system, apart from its colossal importance as a neurotransmission system, seems to also play an important role in brain injury recovery. It has been recently suggested that the brain possesses a cholinergic anti-inflammatory pathway that counteracts the inflammatory responses after ICH, thereby limiting damage to the brain itself. We, herein, report the findings of our study concerning the role of acetylcholinesterase (AChE; a crucial membrane-bound enzyme involved in cholinergic neurotransmission) in a porcine model of spontaneous ICH, with a focus on the first 4 and 24 h following the lesion's induction, in combination with a study of the effectiveness of the lazaroid antioxidant U-74389G administration. Our study demonstrates the activation of AChE activity following U-74389G administration. The lazaroid U-74389G seems to be an established neuroprotectant and this is the first report of its supporting role in the enhancement of cholinergic response to the induction of ICH.

The effects of lazaroid U-74389G in a rat sepsis model.

OBJECTIVE AND DESIGN: To examine the protective effects of a lazaroid, 21-aminosteroid U-74389G, in a rat septic shock model. MATERIALS OR SUBJECTS: Male Sprague-Dawley rats (n = 60) aged 6-8 months. TREATMENT: Groups were exposed to 500 cGy radiation followed by E. coli inoculation, and either placebo or lazaroid injection (10 mg/kg intraperitoneal) 5 days after irradiation. METHODS: Hemodynamic measurements, arterial blood gases, serum lactate, total antioxidative capacity, and cytokine levels were measured at specific time intervals. RESULTS: Treatment with the lazaroid U-74389G maintained cardiac output and mean aortic pressure. Lazaroid treatment also prevented the increase in serum lactate seen in placebo-treated rats. Cytokine serum levels in lazaroid-treated rats were not significantly different from those in placebo-treated rats at any time point. CONCLUSIONS: Lazaroid treatment of E. coli-inoculated septic animals lessens the hemodynamic deterioration seen in sepsis.

Effects of lazaroids on intestinal ischemia and reperfusion injury in experimental models.

Mesenteric ischemia occurs in a number of clinically relevant pathophysiologic processes, including sepsis, hemorrhage, intestinal transplantation, severe burns, and mesenteric thrombosis. The readmission of molecular oxygen into an ischemic tissue promotes the oxidation of resuscitated tissue with certain pathophysiologic mechanisms. Depending on the duration and the intensity of ischemia, reoxygenation of the intestine that has been reperfused may further induce tissue injury. Intestinal ischemia and reperfusion injury can accelerate complex processes between the endothelium and different cell types leading to microvascular injury, cellular necrosis, and apoptosis. The injury due to reperfusion is found predominantly in the intestinal mucosa and submucosa, causing endothelial detachment. The 21-aminosteroids (lazaroids) are a family of compounds that inhibit lipid membrane peroxidation. Many of the performed studies show conflicting results, which reflect differences in experimental design, evolving time that (I/R) is induced, total or partial vascular occlusion, dosage of the lazaroid, and the exact period of time that the lazaroid is administered.

The Effects of Ascorbic Acid and U-74389G on Renal Ischemia-Reperfusion Injury in a Rat Model.

BACKGROUND/AIM: U-74389G and ascorbic acid protect the cells from oxidation. This study aimed to depict their role in ischemia-reperfusion injury in a renal rat model. MATERIALS AND METHODS: Sixty Wistars rats were randomized into six groups of 10 animals each. Group A Ischemia 30 min, reperfusion 60 min; Group B Ischemia 30 min, reperfusion 120 min; Group C Ischemia 30 min, ascorbic acid administration, reperfusion 60 min; Group D Ischemia 30 min, ascorbic acid administration, reperfusion 120 min; Group E Ischemia 30 min, U-74389G administration, reperfusion 60 min; Group F Ischemia 30 min, U-74389G administration, reperfusion 120 min. We then collected tissue and blood samples. RESULTS: Histology and the significantly decreased malondialdehyde and tumor necrosis factor-α levels indicated that ascorbic acid was superior to U-74389G, at pre-defined time intervals. CONCLUSION: Ascorbic acid and U-74389G ameliorated renal damage induced by ischemia-reperfusion injury, suggesting a therapeutic effect.

Pharmacological inhibition of lipid peroxidative damage by the 21-aminosteroid U-74389G improves cortical mitochondrial function following traumatic brain injury in young adult male rats.

The 21-aminosteroid ("lazaroid") U-74389G (U74), an inhibitor of lipid peroxidation (LP), was used to protect mitochondrial function following TBI in young adult male rats. The animals received a severe (2.2 mm) controlled cortical impact-TBI. U74 was administered intravenous at 15 min and 2 h post injury (hpi) followed by intraperitoneal dose at 8 hpi at the following doses (mg/kg): 0.3 (IV) + 1 (IP), 1 + 3, 3 + 10, 10 + 30. Total cortical mitochondria were isolated at 72 hpi and respiratory rates were measured. Mitochondrial 4-HNE and acrolein were evaluated as indicators of LP-mediated oxidative damage. At 72 h post-TBI injured animals had significantly lower mitochondrial respiration rates compared to sham. Administration of U74 at the 1 mg/kg dosing paradigm significantly improved mitochondrial respiration rates for States II, III, V(II) and RCR compared to vehicle-treated animals. At 72 h post-TBI injured animals administration of U74 also reduced reactive aldehydes levels compared to vehicle-treated animals. The aim of this study was to explore the hypothesis that interrupting secondary oxidative damage via acute pharmacological inhibition of LP by U74 following a CCI-TBI would provide mitochondrial neuroprotective effects in a dose-dependent manner. We found acute administration of U74 to injured rats resulted in improved mitochondrial function and lowered the levels of reactive aldehydes in the mitochondria. These results establish not only the most effective dose of U74 treatment to attenuate LP-mediated oxidative damage, but also set the foundation for further studies to explore additional neuroprotective effects following TBI.

Beneficial Effect of U-74389 G and Sildenafil in An Experimental Model of Flap Ischemia/Reperfusion Injury in Swine. Histological and Biochemical Evaluation of the Model.

Purpose of the study: Tissue reconstruction after burns, tumor excisions, infections or injuries is a frequent surgical challenge to avoid Ischemia-reperfusion injury. Lazaroids and sildenafil, through their mechanisms of action, have been studied for their protective effects on various organs subjected to IRI. In this study, we aimed to evaluate the therapeutic potential of U-74389G and sildenafil in a swine model of ischemia and reperfusion injury of latissimus dorsi flap. Materials and methods: Forty-two Landrace male pigs, weighing 28-35 kg, were equally (n = 6) randomized into the following groups: (a) Group I: control, (b) Group II: administration of U-74389G after ischemia, (c) Group III: administration of sildenafil after ischemia, (d) Group IV: administration of U-74389G and sildenafil after ischemia, (e) Group V: administration of U-74389G prior to ischemia, (f) Group VI: administration of sildenafil prior to ischemia, and (g) Group VII: administration of U-74389G and sildenafil prior to ischemia. Blood and tissue sampling was conducted before ischemia, 15 and 30 min after occlusion, 30, 60, 90, and 120 min after reperfusion. Results: Statistically significant reduction (p < 0.05) was detected in lymphocytes and polymorphonuclear leukocytes concentrations as well as in the appearance of edema after histopathologic evaluation of the ischemic tissue, especially in the groups of combined treatment. Measurements of malondialdeyde and tumour necrosis factor alpha in tissues revealed a significant decrease (p < 0.001) of these markers in the treatment groups when compared to the control, particularly in the latest estimated timepoints. Conclusions: The synergistic action of U-74389G and sildenafil seems protective and promising in cases of flap IRI during tissue reconstruction surgery.

The effect of U-74389G on liver recovery after acute liver ischemia-reperfusion injury in a swine model.

BACKGROUND: The potential of U-74389G in attenuating liver damage after ischemia and reperfusion of the liver was studied in a swine model. MATERIALS AND METHODS: Eighteen pigs, weighting 28-35 kg, were used in the study. The animals were divided into the following three experimental groups: Group A (control group): Ischemia time 30 min and reperfusion for 120 min (with tissue and blood sampling at both 60 min (A-60) and 120 min (A-120)); Group B: Ischemia time 30 min, U-74389G intraportal injection, and reperfusion for 60 min; and Group C: Ischemia time 30 min, U-74389G intraportal injection, and reperfusion for 120 min. The dose of U-74389G administered was 10 mg/kg animal body weight. Anesthesia was induced with propofol, pancuronium, and fentanyl. Surgery was performed through a midline laparotomy. The portal vein and the common hepatic artery were isolated and prepared for occlusion. RESULTS: Histopathological evaluation revealed a statistically significant difference in portal infiltration in the liver tissue between control group A-60 and group B (P = 0.01), and between control group A-120 and group C (P = 0.002). Hemodynamic and metabolic data in the control and therapy groups at 0, 30, 60, and 120 min were not statistically significantly different. Tissue malondialdehyde levels were statistically significantly different. Tumor necrosis factor-alpha values were statistically significantly different between groups A-60 and B but not between groups A-120 and C. CONCLUSION: Based on the histological data and the reduction of the malondialdehyde and tumor necrosis factor-alpha levels, administration of U-74389G in ischemia-reperfusion injury of the liver in a swine model has potential in attenuating liver damage.

U74389F, a 21-aminosteroid antioxidant, improves neoendothelial morphology, but not neointimal thickening after balloon catheter injury.

U74389F is a compound in a family of 21-aminosteroids devoid of classical glucocorticoid action that inhibit lipid peroxidation. These compounds improve neurologic function and tissue survival after head or spinal cord injury. Dexamethasone inhibits development of intimal hyperplasia (IH) and improves attenuated nitric oxide (NO) production of the rabbit aorta subsequent to balloon catheter injury. We tested the hypothesis that U74389F is protective in a catheter-induced endothelial-denuded and arterial injury model. A 4-Fr Fogarty balloon (BALL) embolectomy catheter was passed through the thoracic aorta of New Zealand White rabbits treated with 15 mg/kg U74389F (LAZ) 2 days before and 1 week after injury. Animals were killed at 4 weeks after surgical intervention, and formation of IH was determined by calculating the intimal/medial ratio (I/M). The treatment groups of animals were injured untreated (BALL), injured treated (BALL/LAZ), uninjured treated (CONTROL/LAZ), and sham-operated treated (SHAM/LAZ). Scanning electron microscopy revealed that after injury lazaroid treatment produced an improvement of the neoendothelium (alignment in the direction of blood and fewer intercellular gaps) as compared with injured but untreated aortas. Relaxation to acetylcholine (NO formation) was impaired in aortic rings from catheterized animals; lazaroid treatment improved the relaxation to 10-6 mol/L acetylcholine but not to lower concentrations. I/M for SHAM/LAZ, BALL, and BALL/LAZ was 0.02 +/- 0.02, 21.6 +/- 1.6, and 17.2 +/- 2.5, respectively; BALL vs. BALL/LAZ, p < 0.06. An increased contractile response to 120 mmol/L KCl was observed after lazaroid treatment. This is the first report of lazaroid-mediated improvement in the neoendothelial morphology, improved neoendothelial NO generation, and augmented hypopolarizing contractile response, but no attenuation in the development of IH.

Effects of two new steroids and cyproterone on some biomarkers of oxidative stress and serotonergic system on rat prostate and brain.

The purpose of this study was to evaluate the effect of cyproterone acetate (CPA, A) compared with new synthetic steroids 3alpha-acetoxy-5,6-epoxy-16-pregnen-20-one (B) and 17alpha-hydroxy-16beta-methyl-1,4,6-pregnatriene-3,20-dione (C) in rat prostate and brain. Groups of animals were treated either with A, B or C (4 mg kg(-1) day(-1)) by the intraperitoneal route for 5 days. Levels of reduced glutathione (GSH), 5-hydroxy-indole acetic acid (5-HIAA), lipid peroxidation (as thiobarbituric acid reactive substances, TBARS) and the activities of Na(+), K(+)- and total ATPases were assayed in prostate and brain for each group of animals including a control group. No appreciable changes were shown in Na(+), K(+)-ATPase and total ATPases and TBARS on prostate and brain of rats that received A, B and C steroids. However, the levels of GSH and 5-HIAA decreased significantly (P < 0.05) in both tissues for the steroids assayed. It is concluded that CPA and the homologues B and C steroids induce changes in the levels of GSH and serotonin in rat prostate and brain.

21-Aminosteroids attenuate excitotoxic neuronal injury in cortical cell cultures.

We studied the protective efficacy of novel 21-aminosteroids against several forms of neuronal injury in murine cortical cell cultures. Concentrations of 200 nM to 20 microM partially attenuated the damage induced by glucose deprivation, combined oxygen-glucose deprivation, or exposure to NMDA; maximal protection was less than that produced by NMDA antagonists, but the combination of a 21-aminosteroid plus an NMDA antagonist produced a greater benefit than either drug alone. 21-Aminosteroid addition did not attenuate NMDA-induced whole-cell current, but did block almost all of the damage induced by exposure to iron, a protective action consistent with inhibition of free radical-mediated lipid peroxidation. Lipid peroxidation may be a downstream event mediating a portion of the injury triggered by excess stimulation of NMDA receptors.

The combinations C1 esterase inhibitor with coagulation factor XIII and N-acetylcysteine with tirilazad mesylate reduce the leukocyte adherence in an experimental endotoxemia in rats.

The study's objective was to determine the effects of the administration of combinations of C1 esterase inhibitor (C1-INH) with coagulation factor XIII (F XIII) and N-acetylcysteine (NAC) with tirilazad mesylate (TM) on leukocyte adherence and on intestinal functional capillary density during experimental endotoxemia in rats. In a prospective, randomized, controlled animal study, 40 male Wistar rats were divided into 4 groups. Group 1 (CON group) served as control group. Group 2 (LPS group), group 3 (C1-INH+F XIII group) and group 4 (NAC+TM group) received endotoxin infusions (10 mg/kg/h for 2 h). In C1-INH+F XIII group, 100 U/kg b.w. C1-INH and 50 U/kg b.w. F XIII were administered after the first 30 min of endotoxemia. In the NAC+TM group, 150 mg/kg b.w. N-acetylcysteine and 10 mg/kg b.w. Tirilazad mesylate were administered after 30 min of endotoxemia. Leukocyte adherence at venules of the intestinal submucosal layer and functional capillary density in the villi intestinales and in the longitudinal and circular muscle layers were estimated by intravital fluorescence microscopy (IVM). C1-INH+F XIII reduced the count of firmly adherent leukocytes that was increased after LPS administration in the V3 venules (CON group 69 (17-160)/mm2; LPS group 635 (556-814)/mm2; C1-INH+F XIII group 503 (337-646)/mm2). NAC+TM reduced the firmly adherent leukocytes in the V3 venules (NAC+TM group 403 (309-572)/mm2) and in the V1 venules (CON group 55 (16-131)/mm2; LPS group 368 (306-475)/mm2; NAC+TM group 270 (216-308)/mm2) as well. FCD was not impaired after LPS challenge and there was no influence of both combinations on the FCD. We conclude that both drug combinations can reduce the leukocyte adherence in a sepsis model in rats.

Effects of N-acetylcysteine and tirilazad mesylate on intestinal functional capillary density, leukocyte adherence, mesenteric plasma extravasation and cytokine levels in experimental endotoxemia in rats.

INTRODUCTION: The study's objective was to determine the effects of the administration of N-acetylcysteine (NAC) and of tirilazad mesylate (TM) on intestinal functional capillary density, mesenteric plasma extravasation, leukocyte adherence and on cytokine release during experimental endotoxemia in rats. METHODS: In a prospective, randomized, controlled animal study, 80 male Wistar rats were examined in 2 test series. Both series were divided into 4 groups. Group 1 served as control group (CON group). Group 2 (LPS group), group 3 (NAC group) and group 4 (TM group) received endotoxin infusions (10 mg/kg over 2 h). In NAC group 150 mg/kg body weight NAC was administered after the first 30 minutes of endotoxemia intravenously. In TM group, 10 mg/kg body weight TM was administered after the first 30 minutes of endotoxemia intravenously. Animals of the series 1 underwent studies of leukocyte adherence on submucosal venular endothelium of the small bowel wall and intestinal functional capillary density (FCD) in the intestinal mucosa and the circular as well as the longitudinal muscle layer by intravital fluorescence microscopy (IVM). Plasma levels of interleukin 1beta (IL-1beta), interferone gamma (IFN-gamma) and soluble intercellular adhesion molecule1 (s-ICAM 1) as well as white blood cell count (WBC) were estimated. In the animals of the series 2 mesenteric plasma extravasation was determined by IVM and plasma levels of tumor necrosis factor alpha (TNF-alpha), IL-4, IL-6, IL-10 and malondialdehyde (MDA) were estimated. RESULTS: After LPS administration, FCD in the villi intestinales was unchanged and in the longitudinal muscularis layer it was increased. There was no effect of NAC or TM administration on FCD.Although the plasma extravasation was not significantly influenced by LPS administration, TM administration resulted in a lower plasma extravasation in the TM group compared to the other groups. After endotoxin challenge, the firmly adherence of leukocytes to vascular endothelium as a parameter of leukocyte activation in endotoxemia was increased but NAC or TM administration had no influence on leukocyte adherence. The plasma levels of IL-1beta, IL-6, IL-10, TNF-alpha, IFN-gamma and sICAM-1 were increased in the endotoxemic groups (LPS group, NAC group and TM group) and the WBC was decreased compared to controls. IL-4 levels were unchanged during observation period. Plasma MDA levels were not influenced by LPS administration compared to controls. The administration of NAC resulted in lower sICAM-1 and MDA levels compared to the LPS group. The IL-1beta, IL-6, IL-10, TNF-alpha and IFN-gamma plasma levels were not influenced by NAC or TM administration. CONCLUSIONS: In this posttreatment sepsis model in rats, NAC administration resulted in lower sICAM-1 and MDA levels compared to the LPS treated animals. TM administration reduced the plasma extravasation in this model.