Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice.

INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice

Abstract INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Alprostadil attenuates myocardial ischemia/reperfusion injury by promoting antioxidant activity and eNOS activation in rats

Abstract Purpose: To investigate the effect of alprostadil on myocardial ischemia/reperfusion (I/R) in rats. Methods: Rats were subjected to myocardial ischemia for 30 min followed by 24h reperfusion. Alprostadil (4 or 8 μg/kg) was intravenously administered at the time of reperfusion and myocardial infarct size, levels of troponin T, and the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in the serum were measured. Antioxidative parameters, nitric oxide (NO) content and phosphorylated endothelial nitric oxide synthase 3 (p-eNOS) expression in the left ventricles were also measured. Histopathological examinations of the left ventricles were also performed. Results: Alprostadil treatment significantly reduced myocardial infarct size, serum troponin T levels, and CK-MB and LDH activity (P<0.05). Furthermore, treatment with alprostadil significantly decreased malondialdehyde (MDA) content (P<0.05) and markedly reduced myonecrosis, edema and infiltration of inflammatory cells. Superoxide dismutase and catalase activities (P<0.05), NO level (P<0.01) and p-eNOS (P<0.05) were significantly increased in rats treated with alprostadil compared with control rats. Conclusion: These results indicate that alprostadil protects against myocardial I/R injury and that these protective effects are achieved, at least in part, via the promotion of antioxidant activity and activation of eNOS.

Alprostadil attenuates myocardial ischemia/reperfusion injury by promoting antioxidant activity and eNOS activation in rats.

PURPOSE: To investigate the effect of alprostadil on myocardial ischemia/reperfusion (I/R) in rats. METHODS: Rats were subjected to myocardial ischemia for 30 min followed by 24h reperfusion. Alprostadil (4 or 8 µg/kg) was intravenously administered at the time of reperfusion and myocardial infarct size, levels of troponin T, and the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in the serum were measured. Antioxidative parameters, nitric oxide (NO) content and phosphorylated endothelial nitric oxide synthase 3 (p-eNOS) expression in the left ventricles were also measured. Histopathological examinations of the left ventricles were also performed. RESULTS: Alprostadil treatment significantly reduced myocardial infarct size, serum troponin T levels, and CK-MB and LDH activity (P<0.05). Furthermore, treatment with alprostadil significantly decreased malondialdehyde (MDA) content (P<0.05) and markedly reduced myonecrosis, edema and infiltration of inflammatory cells. Superoxide dismutase and catalase activities (P<0.05), NO level (P<0.01) and p-eNOS (P<0.05) were significantly increased in rats treated with alprostadil compared with control rats. CONCLUSION: These results indicate that alprostadil protects against myocardial I/R injury and that these protective effects are achieved, at least in part, via the promotion of antioxidant activity and activation of eNOS.

Can thiamine pyrophosphate prevent desflurane induced hepatotoxicity in rats?

PURPOSE: To investigate the effects of thiamine pyrophosphate (TPP) against desflurane induced hepatotoxicity. METHODS: Thirty experimental animals were divided into groups as healthy (HG), desflurane control (DCG) , TPP and desflurane group (TDG). 20 mg/kg TPP was injected to intraperitoneally TDG. After one hour of TPP administration, desflurane was applied for two hours. After 24 hours, liver tissues of the animals killed with decapitation were removed. The oxidant/antioxidant levels and ALT, AST and LDH activities were measured. The histopathological examinations were performed in the liver tissues for all rats. RESULTS: Notwithstanding the levels of oxidants and liver enzymes were significantly increased (p<0.0001), antioxidant levels were significantly decreased in DCG (p<0.0001). On contrary to the antioxidant parameters were increased (p<0.05) the oxidant parameters and liver enzymes were decreased in TDG (p<0.0001). Whereas multiple prominent, congestion, hemorrhage and dilatation were observed in sinusoids and lymphocyte-rich inflammation results in the centrilobular and portal areas of liver tissue in DCG, these findings were observed less frequently in TDG. CONCLUSION : Thiamine pyrophosphate prevented liver oxidative damage induced with desflurane and may be useful in prophylaxis of desflurane induced hepatotoxicity.

Can thiamine pyrophosphate prevent desflurane induced hepatotoxicity in rats?

ABSTRACT PURPOSE : To investigate the effects of thiamine pyrophosphate (TPP) against desflurane induced hepatotoxicity. METHODS : Thirty experimental animals were divided into groups as healthy (HG), desflurane control (DCG) , TPP and desflurane group (TDG). 20 mg/kg TPP was injected to intraperitoneally TDG. After one hour of TPP administration, desflurane was applied for two hours. After 24 hours, liver tissues of the animals killed with decapitation were removed. The oxidant/antioxidant levels and ALT, AST and LDH activities were measured. The histopathological examinations were performed in the liver tissues for all rats. RESULTS : Notwithstanding the levels of oxidants and liver enzymes were significantly increased (p<0.0001), antioxidant levels were significantly decreased in DCG (p<0.0001). On contrary to the antioxidant parameters were increased (p<0.05) the oxidant parameters and liver enzymes were decreased in TDG (p<0.0001). Whereas multiple prominent, congestion, hemorrhage and dilatation were observed in sinusoids and lymphocyte-rich inflammation results in the centrilobular and portal areas of liver tissue in DCG, these findings were observed less frequently in TDG. CONCLUSİON : Thiamine pyrophosphate prevented liver oxidative damage induced with desflurane and may be useful in prophylaxis of desflurane induced hepatotoxicity.

The TLR7 agonist Imiquimod promote the immunogenicity of mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSCs) are considered the best candidate in stem cells therapy due to their multipotent differentiation ability, low expression of co-stimulatory molecules (CD80, CD86, CD34 and HLA-II) and immunosuppression effects on in vivo immune responses. MSCs were now widely used in clinical trials but received no encourage results. The major problem was the fate of engrafted MSCs in vivo could not be defined. Some studies indicated that MSCs could induce immune response and result in the damage and rejection of MSCs. As toll like receptors (TLRs) are important in inducing of immune responses, in this study we study the role of TLR7 in mediating the immune status of MSCs isolated from umbilical cord. RESULTS: Our results indicated that TLR7 agonist Imiquimod could increase the proliferation of PBMC isolated from healthy human volunteers and release of lactate dehydrogenase (LDH) in supernatant from PBMC-UCMSCs co-culture system. Flow cytometry and quantitative PCR also confirmed the regulated expression of surface co-stimulatory molecules and pro-inflammatory genes (IL-6, IL-8, IL-12, TGF-ß and TNF-α). And the down-regulation expression of stem cell markers also confirmed the loss of stemness of UCMSCs. We also found that the osteo-differentiation ability of UCMSCs was enhanced in the presence of Imiquimod. CONCLUSION: To our knowledge, this is the first report that activation of TLR7 pathway increases the immunogenicity of UCMSCs. Extensive researches have now been conducted to study whether the change of immune status will be help in tumor rejection based on the tumor-tropism of MSCs.

The TLR7 agonist Imiquimod promote the immunogenicity of msenchymal stem cells

BACKGROUND: Mesenchymal stem cells (MSCs) are considered the best candidate in stem cells therapy due to their multipotent differentiation ability, low expression of co-stimulatory molecules (CD80, CD86, CD34 and HLA-II) and immunosuppression effects on in vivo immune responses. MSCs were now widely used in clinical trials but received no encourage results. The major problem was the fate of engrafted MSCs in vivo could not be defined. Some studies indicated that MSCs could induce immune response and result in the damage and rejection of MSCs. As toll like receptors (TLRs) are important in inducing of immune responses, in this study we study the role of TLR7 in mediating the immune status of MSCs isolated from umbilical cord. RESULTS: Our results indicated that TLR7 agonist Imiquimod could increase the proliferation of PBMC isolated from healthy human volunteers and release of lactate dehydrogenase (LDH) in supernatant from PBMC-UCMSCs co-culture system. Flow cytometry and quantitative PCR also confirmed the regulated expression of surface co-stimulatory molecules and pro-inflammatory genes (IL-6, IL-8, IL-12, TGF-β and TNF-α). And the down-regulation expression of stem cell markers also confirmed the loss of stemness of UCMSCs. We also found that the osteo-differentiation ability of UCMSCs was enhanced in the presence of Imiquimod. CONCLUSION: To our knowledge, this is the first report that activation of TLR7 pathway increases the immunogenicity of UCMSCs. Extensive researches have now been conducted to study whether the change of immune status will be help in tumor rejection based on the tumor-tropism of MSCs.

Chitosan and platelet-derived growth factor synergistically stimulate cell proliferation in gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Chitosan is a naturally derived polymer that may be applied in periodontal therapy for tissue-reconstruction purposes. Previous studies have shown that chitosan may stimulate tissue healing. However, reports exploring the cellular responses stimulated by chitosan are lacking. In the present study we analyzed whether chitosan may promote cell proliferation in primary cultures of human gingival fibroblasts. MATERIAL AND METHODS: Chitosan particles were generated, and their size, zeta potential and morphology were characterized using transmission and scanning electron microscopy and zetasizer analysis. The biocompatibility of chitosan particles was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell-viability assay and by detecting the release of lactate dehydrogenase into the cell-culture medium. The total number of cells was estimated by staining with crystal violet followed by measurement of the absorbance at 560 nm on a microplate reader. Cell proliferation was studied by detecting proliferating cell nuclear antigen protein levels, immunofluorescence for Ki67 and incorporation of 5'-bromo-2'-deoxyuridine. RESULTS: The sizes of the chitosan particles generated were in the micrometer and nanometer ranges. Cell viability was increased in the presence of chitosan. Moreover, the combination of chitosan and platelet-derived growth factor (PDGF-BB) potently stimulated cell viability, cell proliferation and activation of the ERK1/2 pathway involved in cell proliferation. CONCLUSIONS: The present study shows that chitosan is well tolerated by gingival fibroblasts and is able to stimulate cell proliferation through the ERK1/2 signaling pathway. A synergistic response between chitosan and growth factors (such as PDGF-BB) may stimulate cell proliferation in gingival fibroblasts exposed to this biomaterial.

Effect of moderate ethanol administration on biochemical indices in streptozotocin-diabetic Wistar rats.

OBJECTIVE: This study was designed to evaluate the effect of moderate ethanol administration on the biochemical indices in streptozotocin (STZ)-diabetic rats. METHODS: Twenty-four male Wistar rats were divided into four groups of six animals each. Groups one and two contained non-diabetic normal rats and normal rats treated with ethanol, respectively. Group three was untreated STZ-diabetic rats and group four was made up of ethanol-treated STZ-diabetic rats. Diabetes was induced by a single intraperitoneal injection of STZ (35 mg/kg), while ethanol (100%v/v) was given at a dose 2 g/kg thrice per week for three weeks. After the last dose of ethanol and an overnight fasting, rats were sacrificed by cervical dislocation. Blood was collected by syringe from the heart into plain centrifuge tubes. RESULTS: Moderate ethanol administration to STZ-diabetic rats caused a significant (p < 0.05) increase in relative weight of liver relative to normal. Ethanol intake in STZ-diabetic rats produced an insignificant (p > 0.05) effect on the levels of fasting blood glucose (FBG) and HbA1c relative to the untreated-diabetic group. Moderately, ethanol administration to STZ-diabetic rats produced a marked and significant (p < 0.05) increase in the levels of serum total cholesterol, triglycerides, low-density lipoprotein (LDL)-cholesterol and the activities of alanine aminotransferase relative to untreated diabetic rats. Ethanol-treated diabetic rats had significantly (p < 0.05) lower high-density lipoprotein (HDL)-cholesterol levels, while the activities of lactate dehydrogenase and alpha-amylase were insignificantly (p > 0.05) affected. There were no significant (p > 0.05) differences in all the biochemical indices in normal rats relative to ethanol-treated normal rats. CONCLUSIONS: Moderate ethanol administration did not affect FBG and HbA1c, but altered the lipid profile of STZ-diabetic rats. Moderate ethanol intake may further increase the risk of complications in diabetes.

Effect of moderate ethanol administration on biochemical indices in streptozotocin-diabetic Wistar rats / Efecto de la administración moderada de etanol sobre los índices bioqumicos en ratas Wistar diabéticas por estreptozotocina

OBJECTIVE: This study was designed to evaluate the effect of moderate ethanol administration on the biochemical indices in streptozotocin (STZ)-diabetic rats. METHODS: Twenty-four male Wistar rats were divided into four groups of six animals each. Groups one and two contained non-diabetic normal rats and normal rats treated with ethanol, respectively. Group three was untreated STZ-diabetic rats and group four was made up of ethanol-treated STZ-diabetic rats. Diabetes was induced by a single intraperitoneal injection of STZ (35 mg/kg), while ethanol (10%v/v) was given at a dose 2 g/kg thrice per week for three weeks. After the last dose of ethanol and an overnight fasting, rats were sacrificed by cervical dislocation. Blood was collected by syringe from the heart into plain centrifuge tubes. RESULTS: Moderate ethanol administration to STZ-diabetic rats caused a significant (p < 0. 05) increase in relative weight of liver relative to normal. Ethanol intake in STZ-diabetic rats produced an insignificant (p > 0. 05) effect on the levels of fasting blood glucose (FBG) and HbA1c rrelative to the untreated-diabetic group. Moderately, ethanol administration to STZ-diabetic rats produced a marked and significant (p < 0. 05) increase in the levels of serum total cholesterol, triglycerides, low-density lipoprotein (LDL)-cholesterol and the activities of alanine aminotransferase relative to untreated diabetic rats. Ethanol-treated diabetic rats had significantly (p < 0. 05) lower high-density lipoprotein (HDL)-cholesterol levels, while the activities of lactate dehydrogenase and α-amylase were insignificantly (p > 0. 05) affected. There were no significant (p > 0. 05) differences in all the biochemical indices in normal rats relative to ethanol-treated normal rats. CONCLUSIONS: Moderate ethanol administration did not affect FBG and HbA1c , but altered the lipid profile of STZ-diabetic rats. Moderate ethanol intake may further increase the risk of complications in diabetes.

OBJETIVO: Este estudio se diseñó con el propósito de evaluar el efecto del uso de etanol moderado sobre los índices bioquímicos en ratas Wistar diabéticas por estreptozotocina (STZ). MÉTODOS: Veinticuatro ratas Wistar machos fueron divididas en cuatro grupos de seis animales cada uno. Dos de los grupos tenían ratas normales no diabéticas y ratas normales tratadas con etanol, respectivamente. El tercer grupo estaba formado por ratas diabéticas por STZ no tratadas, y el cuarto por ratas diabéticas por STZ tratadas con etanol. La diabetes fue inducida mediante una inyección intraperitoneal de STZ (35 mg/kg), mientras que el etanol (10% v/v) fue administrado en dosis de 2 g/kg tres veces por semana durante tres semanas. Tras la última dosis de etanol y un ayuno de una noche, las ratas fueron sacrificadas mediante dislocación cervical. La sangre fue recogida del corazón con jeringuillas e introducida en tubos para centrífuga sin graduación. RESULTADOS: La administración moderada de etanol a ratas diabéticas por STZ, causó un aumento significativo (p < 0.05) en el peso relativo del hígado con relación al normal. La ingestión de etanol en ratas diabéticas por STZ tuvo un efecto insignificante (p > 0.05) en los niveles de glucosa en sangre en ayuno (GSA) y HbA1c en relación con grupos diabéticos no tratados. En medida moderada, la administración de etanol a ratas diabéticas por STZ produjo un aumento marcado y significativo (p < 0.05) en los niveles de colesterol total en suero, triglicéridos, el colesterol asociado con las lipoproteínas de baja densidad, o colesterol LDL, y la actividad de la aminotransferasa alanina en relación con las ratas diabéticas no tratadas. Las ratas diabéticas tratadas con etanol tuvieron niveles significativamente disminuidos de colesterol asociado con las lipoproteínas de alta densidad, o colesterol HDL, en tanto que la actividad del lactato deshidrogenasa y la α-amilasa no fue afectada significativamente (p > 0.05). No hubo diferencias significativas (p > 0.05) en todos los índices bioquímicos en las ratas normales con respecto a las ratas normales tratadas con etanol. CONCLUSIONES: El suministro moderado de etanol no afectó el GSA ni el HbA1c , pero alteró el perfil lípido de las ratas diabéticas por STZ. La ingestión moderada de etanol puede aumentar a un más el riesgo de las complicaciones de la diabetes.

Effect of N-acetylcysteine on markers of skeletal muscle injury after fatiguing contractile activity.

The effects of N-Acetylcysteine (NAC), an unspecific antioxidant, on fatiguing contractile activity-induced injury were investigated. Twenty-four male Wistar rats were randomly assigned to two groups. The placebo group (N=12) received one injection of phosphate buffer (PBS) 1 h prior to contractile activity induced by electrical stimulation. The NAC group (NAC; N=12) received electrical stimulation for the same time period and NAC (500 mg/kg, i.p.) dissolved in PBS 1 h prior to electrical stimulation. The contralateral hindlimb was used as a control, except in the analysis of plasma enzyme activities, when a control group (rats placebo group not electrically stimulated and not treated) was included. The following parameters were measured: tetanic force, muscle fatigue, plasma activities of creatine kinase (CK) and lactate dehydrogenase (LDH), changes in muscle vascular permeability using Evans blue dye (EBD), muscle content of reactive oxygen species (ROS) and thiobarbituric acid-reactive substances (TBARS) and myeloperoxidase (MPO) activity. Muscle fatigue was delayed and tetanic force was preserved in NAC-treated rats. NAC treatment decreased plasma CK and LDH activities. The content of muscle-derived ROS, TBARS, EBD and MPO activity in both gastrocnemius and soleus muscles were also decreased by NAC pre-treatment. Thus, NAC has a protective effect against injury induced by fatiguing contractile activity in skeletal muscle.

Protein tyrosine phosphatase alpha regulates cell detachment and cell death profiles induced by nitric oxide donors in the A431 human carcinoma cell line.

We investigated the role of protein tyrosine phosphatase-alpha (PTPα) expression in the cell death profile of the A431 human carcinoma cell line that was induced by cytotoxic concentrations of the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3,3-bis-(aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18). Both NO donors promoted extensive cell detachment in A431 parental cells as compared to the detachment observed for A431 cells that ectopically expressed PTPα (A431 (A27B(PTPα)) cells). The NO-induced cell death characteristics for both cell lines were examined. After incubation for 10 hours with 2.0 mM SNP, attached or detached A431 cells underwent apoptosis. Cells were highly positive for Annexin-V, featured increased cleavage of procaspase-8, activation of downstream caspase-3, and activation of poly-ADP-ribose polymerase 1 (PARP-1). In contrast, exposure of A431 (A27B(PTPα)) cells to 2.0 mM SNP produced an increase in the release of lactate dehydrogenase and enhanced incorporation of propidium iodide. In addition, A431 (A27B(PTPα)) cells showed partial inhibition of the activities of caspase-8, caspase-3, and PARP-1 upon detachment and cell death induced by SNP treatment. Results indicate that necrotic cell damage was induced, characterized by cellular swelling and lysis. We conclude from these results that PTPα regulates the A431 tumor cell death profile mediated by NO donors. Expression of PTPα or its absence may determine the occurrence of NO-induced cell death with necrotic or apoptotic features, respectively.

Allopregnanolone effects on astrogliosis induced by hypoxia in organotypic cultures of striatum, hippocampus, and neocortex.

UNLABELLED: Perinatal asphyxia occurs in approximately 0.3% full-term newborn babies, and this percentage has not decreased despite medical advances. There are now evidences indicating that neurosteroids are important in neurodevelopment showing neuroprotective effects. We studied the potential protective effect of allopregnanolone (Allo) in vitro using organotypic cultures from neocortex, striatum, and hippocampus. Immunocytochemistry and confocal microscopy showed an increase of the glial fibrillary acidic protein (GFAP) signal in the studied brain areas after hypoxia. Western blot studies supported these results (hippocampus, 193%; neocortex, 306%; and striatum, 231%). Twenty-four-hour pretreatment with Allo showed different effects at the brain areas studied. In the hippocampus and the neocortex, 24-h pretreatment with Allo 5x10(-6) M showed to be neuroprotective as there was a significant decrease of the GFAP signal compared to control cultures exposed to hypoxia. Pretreatment with 5x10(-8) M Allo attenuated the astrogliosis response in the hippocampus and the neocortex in a nonsignificant way. Allo pretreatment at all doses did not show to affect the astrogliosis triggered by hypoxia in the striatum. Cell survival was analyzed by measuring LDH. After 1 h of hypoxia, all cultures showed a nonsignificant increase of LDH, which was greater after 24 h of hypoxia (hippocampus, 180%; striatum-cortex co-cultures, 140%). LDH levels have no changes by Allo pretreatment before hypoxia. CONCLUSION: 24 h pretreatment with 5x10(-6) M of Allo does not change neuronal viability but it prevents astrogliosis induced by hypoxia in the hippocampus and the neocortex.

Deleterious versus neuroprotective effect of metabolic inhibition after traumatic spinal cord injury.

STUDY DESIGN: This work is an experimental and prospective study in adult, female, Long-Evans rats. OBJECTIVES: The aim of this study was to probe the effect of metabolic inhibition after an acute traumatic spinal cord injury (TSCI) using a standardized contusion model (NYU impactor) to know whether the metabolic inhibition is a 'secondary mechanism of injury' or a mechanism of protection. SETTING: All experimental procedures were carried out in the Mexico City. METHODS: Animals were divided into five groups: one sham and four with TSCI, including no treatment, rotenone (inhibitor of mitochondrial complex I), sodium azide (inhibitor of mitochondrial complex IV) and pyrophosphate of thiamine or non-degradable cocarboxylase as a metabolic reactivator. RESULTS: After TSCI, the metabolic inhibition with sodium azide treatment diminished the lipid peroxidation process (malondialdehyde levels by spectrophotometric procedures) and the damage to the spinal cord tissue (morphometric analysis), and increased the activity of creatine kinase and lactate dehydrogenase enzymes (P<0.05) (measured by spectrophotometric procedures 24 h after TSCI as well as after the functional recovery of the hind limb (evaluated weekly for 2 months by the BBB (Basso, Beattie and Bresnahan) scale)) when compared with the TSCI group without treatment. CONCLUSION: The results show that the partial and transitory inhibition of the aerobic metabolism after an acute TSCI could be a self-protection mechanism instead of being a 'secondary mechanism of injury'.

Role of purines on hepatic ischemia-reperfusion lesions in rabbit.

In this work, we evaluate the effects of adenosine 5' triphosphate (ATP) on hepatic lesions caused by ischemia/reperfusion (I/R) in liver rabbit. Rabbits were pretreated with ATP (15 mg/kg IV) or saline solution 0.9% (SS), before the hepatic I/R procedure. We evaluated the effects of ATP on hepatic injury before and after I/R. The warm hepatic I/R procedure caused profound acute liver injury, as indicated by elevated serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, as well as a high apoptotic cell count. All these changes were attenuate by ATP treatment before the hepatic I/R procedure. These results suggested that ATP exerted protective effects on hepatic I/R lesions in the rabbit. This ATP effect may be related to improved energy metabolism during reperfusion in ischemic livers protecting against functional damage of cellular and subcellular membranes during lipid peroxidation.

l-Arginine supplementation protects against hepatic ischemia-reperfusion lesions in rabbits.

We evaluated the effects of a substrate in the biosynthesis of nitric oxide (NO)-l-arginine (LARG)-on hepatic lesions caused by ischemia/reperfusion (I/R) injury in rabbit livers. Rabbits were pretreated with LARG (150 mg/kg IV) or saline solution 0.9% (SS) before the hepatic I/R procedure. The effects of LARG on hepatic injury were evaluated before and after I/R. The warm hepatic I/R procedure produced profound acute liver injury, as indicated by elevated values of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactic dehydrogenase (LDH), as well as a high apoptotic cell count. All changes were attenuated by treatment with LARG before the hepatic I/R procedure. These results suggested that LARG produced protective effects on hepatic I/R lesions. This protective effect of LARG was probably associated with blocking generation of superoxide anions during the hepatic I/R procedure.

Protective effects of heparin on hepatic ischemia and reperfusion lesions in rabbits.

Because the role of heparin (HEP) in hepatic ischemia/reperfusion (I/R) injury is still not fully understood, we investigated the effects of treatment with HEP on hepatic I/R injury in rabbits. For I/R procedures, the portal vein and hepatic artery were occluded by a metallic clamp to promote ischemia. The clamp was removed after 30 minutes to allow reperfusion. Rabbits undergoing the I/R procedure were treated with HEP (100 U/kg) or saline solution 0.9% (SS). When compared with levels before I/R, the serum aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, levels were increased by the hepatic I/R procedure, among rabbits treated with SS or HEP. However, the increase in these enzymes was lower among rabbits treated with HEP. Histologic analysis of hepatic tissue of rabbits undergoing I/R and treated with SS showed marked lesions in the central lobule with significant inflammatory infiltration. In contrast, a significant reduction in lesions caused by I/R was observed in the livers of rabbits treated with HEP. After starting reperfusion, we visualized apoptotic cells with nuclear staining among rabbits submitted to I/R and treated with SS, but not those treated with HEP. These results suggested that HEP was able to attenuate hepatic lesions caused by I/R in the livers of rabbits.

Effects of allopurinol on ischemia and reperfusion in rabbit livers.

In this work, we evaluated the effects of allopurinol (ALO), an inhibitor of xanthine oxidase (XO), on hepatic lesions caused by ischemia/reperfusion (I/R) in the rabbit liver. Rabbits were pretreated with ALO (10 mg/kg IV) or saline solution 0.9% before the hepatic I/R procedure. The effects of ALO on hepatic injury were evaluated before and after I/R. A standard, warm hepatic I/R procedure caused profound acute liver injury, as indicated by elevated serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, as well as a high apoptotic cell count. All of these changes were reversed by the administration of ALO before the hepatic I/R procedure. In conclusion, ALO exerted protective effects on hepatic I/R lesions. This protective effect of ALO was probably associated with blocking the generation of superoxide anions during the hepatic I/R procedure by inhibiting XO activity.

Conjugated linoleic acid and cardiac health: oxidative stress and energetic metabolism in standard and sucrose-rich diets.

Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n=6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO(2)/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions, and triacylglycerol accumulation in S-CLA rats. Conjugated linoleic acid depressed myocardial LDH comparing C-CLA with C, and beta-hydroxyacyl-coenzyme-A dehydrogenase/CS ratio, comparing S-CLA with S. In conclusion, dietary conjugated linoleic acid supplementation for weight loss can have long-term effects on cardiac health. Conjugated linoleic acid, isomers c9, t11 and t10, c12c9,t11" and "t10,c12" were changed to "c9, t11" and "t10, c12", respectively. Please check if appropriate.--> presented undesirable pro-oxidant effect and induced metabolic changes in cardiac tissue. Nevertheless, despite its effect on abdominal adiposity in sucrose-rich diet condition, conjugated linoleic acid may be disadvantageous because it can lead to oxidative stress and dyslipidemic profile.