ATPase Levels Research Articles

Sperm dynein ATPase and ATPases associated with various cellular activities (AAA+): regulation in oligo-astheno-teratozoospermia and necrozoospermia as extreme sperm motility disorders

Asthenozoospermia is the most frequent sperm motility disorder, but there are other more extreme sperm motility disorders, namely oligo-astheno-teratozoospermia (OAT) and necrozoospermia. There are several cellular mechanisms known for OAT and necrozoospermia, but there are limited data on dynein ATPase and ATPases associated with various cellular activities (AAA+). AAA1 is involved in ATP hydrolysis, while AAA2 is entangled in ATP-binding pocket. This study was conducted to investigate the role of dynein ATPase activity and quantification of AAA dynein. Spermatozoa from 14 men with OAT, 11 men with necrozoospermic and 17 men with normoozspermic samples were used in this study. Makler chamber was used to determine sperm concentration and motility, while Papanicolaou stained semen smears using World Health Organization-fifth edition criteria was performed to determine sperm morphology, and dynein ATPase was quantified by calculation of released inorganic phosphate. AAA was quantified by enzyme-linked immunosorbent assay, whereas the distribution was determined by immunocytochemistry. This study showed that the dynein ATPase activity in OAT and necrozoospermia was lower than in the normozoospermic group (2.68±0.76, 1.01±0.31, 7.22±1.08 μmol Pi/mg protein/h, respectively, P<0.05), as well as the amounts of AAA1 and AAA2. In addition, staining for AAA in the sperm tail paralleled the dynein ATPase activity and quantity of AAA, being the highest in sperm from normozoospermic samples, lower in sperm from OAT samples, and almost undetectable in sperm from necrozoospermic samples. The structure and function of damaged sperm dynein may alter dynein ATPase activity and levels of AAA1 and AAA2.

Mitochondrial response of the lesser grain borer Rhyzopertha dominica (F.) to modified atmospheres

Rhyzopertha dominica is an insect pest that feeds on a wide variety of grains and stored cereals, producing economical losses. Bioenergetics studies on insects are necessary to eventually plan strategies to reduce pest infestation on stored grains with methods other than insecticides. Modified atmosphere treatments, where insects are exposed to either low O2 or high CO2 concentrations, or both, can be used as alternatives. In this research, R. dominica was subjected to a modified atmosphere environment (MA) consisting of 5% O2 and 10% CO2 for 24 h and was compared with normoxia insects (21% O2 and 0.02% CO2). Mitochondria from the whole insect were isolated and their protein content was analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) using OFFGEL Fractionator equipment and 12% polyacrylamide gels electrophoresis (SDS-PAGE). Lactate concentration, cytochrome c oxidase (COX) and ATPase activities were measured. Lactate concentration was 29% higher in R. dominica exposed to MA versus normoxia. 2-D PAGE and LC MS/MS revealed the presence of a heat shock protein (hsp60), an actin fragment, and ATP synthase α and β catalytic subunits. Activity levels of COX and ATPase were reduced by 58 and 59%, respectively, in MA versus normoxia. Therefore, R. dominica may have shifted into a hypo-metabolic state because oxygen intake was insufficient to maintain enzymatic activity. This scenario would ultimately result in a decrease in substrate concentration (oxygen) and a reduction in electron transport chain complex activity. Thus, eventually, this knowledge can be use to develop novel environmentally friendly alternatives to eradicate or reduce pests in stored grains.

Investigation of dose-dependent effects of berberine against renal ischemia/reperfusion injury in experimental diabetic rats

BackgroundIschemia–reperfusion injury causes various severe morphological and functional changes in diabetic patients. To date, numerous antidiabetic and antioxidant agents have been used for treatment of the disease-related changes. ObjectivesWe aimed to examine effective therapeutic doses or doses of berberine against renal ischemia/reperfusion injury (IRI) in a streptozotocin (STZ)-induced diabetic rat model by histopathological and biochemical analysis. MethodsThirty male Sprague Dawley rats were treated with STZ injection for the development of diabetes, and divided into the following groups: STZ-induced diabetic group (STZ); IRI-induced diabetic group (STZ+IRI); 50mg/kg berberine (BRB) treated diabetic group after inducing IRI (STZ+IRI+BRB1); 100mg/kg BRB treated diabetic group after IRI (STZ+IRI+BRB2); 150mg/kg BRB treated diabetic group after IRI (STZ+IRI+BRB3). Bilateral renal ischemia model was applied for 45min, then reperfusion was allowed for 14 days in STZ-induced diabetic rats. Renal injury was detected histopathologically. Blood urea nitrogen (BUN), creatinine and lactate dehydrogenase (LDH) levels were measured in serum using the ELISA method. Total antioxidant status (TAS) and total oxidant status (TOS) of renal tissue was studied by spectrophotometric assay. Oxidative stress index (OSI) was calculated as TOS-to-TAS ratio. Tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), Na+/K+-ATPase (sodium pump), and Ca2+-ATPase (calcium ATPase) enzyme levels were measured in tissues using the ELISA method. Anti-apoptotic Bax and pro-apoptotic Bcl-2 protein levels were detected by Western blot analysis. All data were evaluated statistically. ResultsThe highest histopathological score was detected in the STZ+IRI group compared to the other group. BRB administration at the doses of 100mg/kg and 150mg/kg markedly improved renal injury. BUN and creatinine levels significantly increased in the STZ+IRI group compared to the STZ group (p<0.001). 100mg/kg and 150mg/kg BRB administration significantly decreased those levels (p<0.01). The highest TOS and the lowest TAS levels were detected in the STZ+IRI group (p<0.001). IRI markedly aggravated inflammation via increasing levels of TNF-α and CRP (<0.001), and caused apoptosis via inducing Bcl-2 protein, and suppressing Bax protein (p<0.001). BRB administration at the doses of 100mg/kg and 150mg/kg showed anti-oxidant, anti-inflammatory and anti-apoptotic effects (p<0.01). The LDH enzyme, was used as a necrosis marker, was higher in the STZ+IRI group than other groups. BRB administration at all of the doses, resulted in the decline of LDH enzyme level (p<0.001). Ca2+-ATPase and Na+/K+-ATPase enzyme activities decreased in the STZ+IRI group compared to the STZ group (p<0.001), while BRB administration at the doses of 100mg/kg and 150mg/kg significantly increased those of enzyme activities, respectively (p<0.05). ConclusionIschemia with diabetes caused severe histopathological and biochemical damage in renal tissue. The high doses of berberine markedly improved histopathological findings, regulated kidney function via decreasing BUN and creatinine levels, and rearranged intercellular ion concentration via increasing Na+/K+-ATPase and Ca2+− ATPase levels. Berberine showed anti-oxidant, anti-apoptotic, and anti-inflammatory effects. According to these data, we suggest that berberine at the doses of 100 and 150mg may be used as a potential therapeutic agent to prevent renal ischemic injury.

Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine modulates glucose homeostasis by enhancing insulin secretion and inhibiting redox imbalance in a rat model of diabetes induced by high fructose diet and streptozotocin

Ethnopharmacological relevanceRaffia palm (Raphia hookeri) wine (RPW) is amongst the natural products from plants, utilized singly or in combination with other medicinal plants for the treatment of several ailments including Diabetes Mellitus (DM). However, there is a scientific dearth on its antidiabetic activity. AimThe antidiabetic effect of RPW and its possible mechanism of actions were investigated in diabetic rats. MethodsFour groups of male SD rats were first supplied with 10% fructose solution ad libitum for 2 weeks instead of drinking water followed by an intraperitonial injection of streptozotocin (40 mg/kg) to induce diabetes. Two diabetic groups were administered RPW at 150 and 300 mg/kg bodyweight (BW) respectively; a group was administered with metformin, while the other one was served as a negative control. Two groups of normal rats were administered with water and RPW (300 mg/kg BW) and served as normal control and normal toxicology group, respectively. ResultsFive weeks treatment of RPW led to significant (p < 0.05) increase in serum insulin and HDL-c levels with concomitant reduction in blood glucose, fructosamine, ALT, uric acid, triglycerides and LDL-c levels in diabetic rats. Rats treated with RPW had elevated levels of GSH, SOD, catalase, ATPase and α-amylase activities, while reduced NO level and myeloperoxidase activity was observed in their serum and pancreatic tissues. RPW also improved pancreatic β-cell function and restored β- and acinar cells morphology, and capillary networks. The activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose-6-phosphatase, and acetylcholinesterase were also inhibited in RPW-treated diabetic rats, with concomitant down regulation of Nrf2 gene expression. ConclusionThe data of this study suggest that RPW modulates glucose homeostasis by enhancing insulin secretion as well as inhibiting redox imbalance in diabetic rats, which may be attributed to the synergetic effects of its phytochemical constituents as identified by GC-MS analysis.

Na+/K+-ATPase level and products of lipid peroxidation in live cells treated with therapeutic lithium for different periods in time (1, 7, and 28days); studies of Jurkat and HEK293 cells.

Regulation of Na+/K+-ATPase in bipolar disorder and lithium therapy has been investigated for more than 40years. Contradictory results in this area may be caused by the difference between acute and long-term Li effects on cell metabolism and variance in responsiveness of different cell types. We compared the time-course of Li action focusing on Na+/K+-ATPase and lipid peroxidation in two widely different cell models-Jurkat and HEK293. Na+/K+-ATPase expression level was determined in cells cultivated in the absence or presence of 1mM Li for different time spans (1, 7, and 28days) using [3H] ouabain binding and immunoblot assay of α-subunit. In parallel samples, the formation of malondialdehyde (MDA) was quantified by HPLC, and 4-hydroxy-2-nonenal (4-HNE) protein adducts were determined by immunoblot. Cultivation of Jurkat cells in 1mM Li medium resulted in downregulation of Na+/K+-ATPase (decrease of [3H] ouabain-biding sites and intensity of immunoblot signals) in all Li-groups. In HEK293 cells, the decrease of Na+/K+-ATPase was observed after the acute, 1-day exposure only. The long-term treatment with Li resulted in Na+/K+-ATPase upregulation. MDA and 4-HNE modified proteins were decreased in Jurkat cells in all Li-groups. On the other hand, in HEK293 cells, MDA concentration was decreased after the acute, 1-day Li exposure only; the long-term cultivations, for 7 or 28days, resulted in a significant increase of lipid peroxidation products. The Li-induced decrease of lipid peroxidation products was associated with the decrease of Na+/K+-ATPase level and vice versa.

Does Oxytocin Have A Neuro-protective Impact in Rats’ Stroke Model?

Background: Stroke is a causative factor of disabilities and death. Various mechanisms involved in the cerebral ischemia-reperfusion pathophysiology, including oxidative stress along with inflammation. Aim: This research assessed the impact of oxytocin in lessening the detrimental effects of reperfusion in the cerebral ischemia/reperfusion (I/R) injury with the causal mechanisms. Materials: The cerebral ischemia-reperfusion injury was elicited by bilateral common carotid artery obstruction for 30 min followed by reperfusion for 24 h in rats. Forty eight rats were divided into: sham-operated group, oxytocin control group (underwent sham operation and given intraperitoneal oxytocin at a dose 750 µg/kg body weight), ischemia and reperfusion group and oxytocin-treated-ischemia and reperfusion group underwent I/R injury and given oxytocin 15 min before perfusion. Total antioxidant capacity, total peroxide, oxidative stress index, tumor necrosis factor-alpha and sodium/potassium-ATPase (Na+/K+-ATPase) level were measured in the cerebral homogenate. Histopathological analyses using H&E stain were carried out. Results: Administration of oxytocin lowered the ischemia-reperfusion-induced elevations in the cerebral total peroxide, oxidative stress index and tumor necrosis factor-alpha concentrations and increased total antioxidant capacity concentration and Na+/K+-ATPase level. Together, these changes were associated with alleviated histopathological alteration-induced by ischemia-reperfusion injury. Conclusion: Oxytocin has a neuro-protective impact against the deleterious effects of reperfusion via amelioration of oxidative stress, and inflammation and restoration of the declining level of the Na+/K+-ATPase. Thus, OT probably has a therapeutic impact on ischemic stroke.

Investigation of dose-dependent effects of berberine against renal ischemia/reperfusion injury in experimental diabetic rats

BackgroundIschemia–reperfusion injury causes various severe morphological and functional changes in diabetic patients. To date, numerous antidiabetic and antioxidant agents have been used for treatment of the disease-related changes. ObjectivesWe aimed to examine effective therapeutic doses or doses of berberine against renal ischemia/reperfusion injury (IRI) in a streptozotocin (STZ)-induced diabetic rat model by histopathological and biochemical analysis. MethodsThirty male Sprague Dawley rats were treated with STZ injection for the development of diabetes, and divided into the following groups: STZ-induced diabetic group (STZ); IRI-induced diabetic group (STZ+IRI); 50mg/kg berberine (BRB) treated diabetic group after inducing IRI (STZ+IRI+BRB1); 100mg/kg BRB treated diabetic group after IRI (STZ+IRI+BRB2); 150mg/kg BRB treated diabetic group after IRI (STZ+IRI+BRB3). Bilateral renal ischemia model was applied for 45min, then reperfusion was allowed for 14 days in STZ-induced diabetic rats. Renal injury was detected histopathologically. Blood urea nitrogen (BUN), creatinine and lactate dehydrogenase (LDH) levels were measured in serum using the ELISA method. Total antioxidant status (TAS) and total oxidant status (TOS) of renal tissue was studied by spectrophotometric assay. Oxidative stress index (OSI) was calculated as TOS-to-TAS ratio. Tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), Na+/K+-ATPase (sodium pump), and Ca2+-ATPase (calcium ATPase) enzyme levels were measured in tissues using the ELISA method. Anti-apoptotic Bax and pro-apoptotic Bcl-2 protein levels were detected by Western blot analysis. All data were evaluated statistically. ResultsThe highest histopathological score was detected in the STZ+IRI group compared to the other group. BRB administration at the doses of 100mg/kg and 150mg/kg markedly improved renal injury. BUN and creatinine levels significantly increased in the STZ+IRI group compared to the STZ group (p<0.001). 100mg/kg and 150mg/kg BRB administration significantly decreased those levels (p<0.01). The highest TOS and the lowest TAS levels were detected in the STZ+IRI group (p<0.001). IRI markedly aggravated inflammation via increasing levels of TNF-α and CRP (<0.001), and caused apoptosis via inducing Bcl-2 protein, and suppressing Bax protein (p<0.001). BRB administration at the doses of 100mg/kg and 150mg/kg showed anti-oxidant, anti-inflammatory and anti-apoptotic effects (p<0.01). The LDH enzyme, was used as a necrosis marker, was higher in the STZ+IRI group than other groups. BRB administration at all of the doses, resulted in the decline of LDH enzyme level (p<0.001). Ca2+-ATPase and Na+/K+-ATPase enzyme activities decreased in the STZ+IRI group compared to the STZ group (p<0.001), while BRB administration at the doses of 100mg/kg and 150mg/kg significantly increased those of enzyme activities, respectively (p<0.05). ConclusionIschemia with diabetes caused severe histopathological and biochemical damage in renal tissue. The high doses of berberine markedly improved histopathological findings, regulated kidney function via decreasing BUN and creatinine levels, and rearranged intercellular ion concentration via increasing Na+/K+-ATPase and Ca2+− ATPase levels. Berberine showed anti-oxidant, anti-apoptotic, and anti-inflammatory effects. According to these data, we suggest that berberine at the doses of 100 and 150mg may be used as a potential therapeutic agent to prevent renal ischemic injury.

Galangin ameliorates changes of membrane–bound enzymes in rats with streptozotocin–induced hyperglycemia

Objective: To assess the protective effect of galangin on membrane bound enzymes in rats with streptozotocin-induced diabetes. Methods: A single low dose of streptozotocin was injected to adult male albino rats to induce hyperglycemia. Galangin (8 mg/kg) or glibenclamide 600 μg/kg as a standard drug was given orally once daily for 45 days by gavage. Membrane-bound adenosine triphosphatases were determined including total ATPase, sodium-potassium-ATPase, calcium-ATPase and magnesium-ATPase in erythrocytes and tissues (kidney, liver, and heart). Results: The levels of total ATPases, sodium-potassium-ATPase, calcium-ATPase and magnesium-ATPase in erythrocytes and tissues were significantly altered in diabetic rats as compared to that in normal rats. After 45 days of treatment with galangin or glibenclamide, the levels of these enzymes were similar to that of normal control rats. Conclusions: Oral administration of galangin or glibenclamide can improve activities of these membrane-bound ATPases towards normal levels. Mechanism of galangin needs to be further explored in future.

Berberine Suppresses RANKL-Induced Osteoclast Differentiation by Inhibiting c-Fos and NFATc1 Expression.

Osteoporosis is a common disorder of bone remodeling, marked by excessive osteoclast formation. Recent studies indicated that berberine (BBR) is a potential natural drug for the treatment of various bone diseases. However, it still needs to be further studied for the treatment of osteoporosis. The current study investigated the inhibitory effects of BBR on receptor activator of nuclear factor- B ligand (RANKL)-induced osteoclast differentiation in vitro and in vivo. Cell-based assays were performed using osteoclasts generated in cultures of murine bone marrow-derived macrophages (BMMs) treated with RANKL and M-CSF. The effects of BBR on in vivo lipopolysaccharide (LPS)-mediated bone loss were evaluated using ICR mice. BBR significantlyinhibited TRAP-positive osteoclast formation induced by RANKL. BBR also inhibited RANKL-induced Akt, p38 and ERK phosphorylation and I B degradation, and suppressed RANKL-induced expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1), which is a key transcription factors for osteoclast formation. BBR reduced the mRNA levels of osteoclast markers, including TRAP, osteoclast-associated receptor (OSCAR), cathepsin K, and ATPase H transporting V0 subunit d2 (ATP6v0d2).Moreover, BBR prevented LPS-mediated bone loss in vivo. We suggest BBR as a natural compound that can be a potential therapeutic agent for osteoclast-related bone diseases.

Myocardial apoptosis and anti-apoptotic mechanism of captopril on cardiac arrest after resuscitation of pulmonary embolism

Objective To observe the myocardial apoptosis and the molecular mechanism of captopril inhibiting myocardial apoptosis on cardiac arrest (CA) after resuscitation in a porcine acute pulmonary embolism (APE) model. Methods In this study, 29 inbred Beijing Landrace were randomly (random number)divided into four groups (n=5, each group): control, APE-CA, restoration of spontaneous circulation (ROSC)-captopril, and ROSC-saline. The model of CA and ROSC was induced by APE through injection of thrombus followed by cardiopulmonary resuscitation and thrombolytic therapy (urokinase, 15 000 U/kg, iv). Ten of 19 pigs with CA recovered to spontaneous circulation were divided randomly into the ROSC-captopril and ROSC-saline groups. Pigs in the ROSC-captopril group were treated with captopril (22.22 mg/kg) via porcine femoral vein at 30 min after ROSC. Pigs in the ROSC-saline group were treated with equal normal saline at 30 min after ROSC. The myocardial tissues were evaluated at 6 h after ROSC. Western blot was used to evaluate the protein levels of Bax, Bcl-2, Caspase-3, phosphorylated (p)-Src and phosphorylated extracellular regulated protein kinase (p-ERK1/2). Immunohistochemistry was used to evaluate the protein expression of p-Src and p-ERK1/2. Enzyme-linked immunosorbent assay was used to detect myocardial Na+-K+-ATPase levels. Statistical analysis was performed using one-way analysis of variance and pearson correlation test. Results Compared with the control group, the protein expression of Bax (0.25±0.01, 0.53±0.01, 0.37±0.05, F=14.16, P<0.05) and Caspase-3 (0.24±0.01, 0.33±0.01, 0.34±0.06, F=7.32, P<0.05) in the APE-CA and ROSC- saline group were increased significantly, and the Bcl-2 expression was significantly decreased (0.56±0.02, 0.19±0.01, 0.37±0.10, F=6.68, P<0.05). Captopril reduced the protein levels of Caspase-3 and Bax, while stimulated the Bcl-2 expression (all P<0.05). Compared with the control group, the protein expression of p-Src and p-ERK1/2 were higher and the Na+-K+-ATPase level was decreased on CA and ROSC induced by APE (all P<0.05). Compared with the APE-CA group, the p-Src expression in the ROSC-captopril group (0.46±0.01 vs. 0.35±0.06, P<0.05) was decreased significantly. Captopril inhibited the activation of p-ERK1/2 than saline group (0.41±0.10 vs. 0.26±0.07, P<0.05), but has no effect on the Na+-K+-ATPase level. The protein expression of p-Src and p-ERK1/2 were positively correlated with the Bax, and negatively correlated with the Bcl-2 respectively. The myocardial Na+-K+-ATPase level negatively correlated with Caspase-3 protein expression. Conclusions The molecular mechanism of cardiomyocyte apoptosis on CA and ROSC induced by APE might be related to decreased Na+-K+-ATPase level and activation of p-Src and p-ERK1/2. The cardiomyocyte apoptosis were inhibited by captopril through reducing the expression of p-Src and p-ERK1/2 in myocardium. Key words: Acute pulmonary embolism; Cardiac arrest; Spontaneous circulation recovery; Myocardial apoptosis; Molecular mechanism

Amelioration of sperm immobilisation factor-induced infertility by bacterial antigenic determinants cross-reacting with spermatozoa.

A strain of Staphylococcus aureus, capable of invitro immobilisation of human and mouse spermatozoa, was already present in our laboratory. Therefore, in the present study, the factor responsible (sperm immobilisation factor, SIF) was isolated and purified. It was found to compromise not only motility, but also viability, morphology and Mg2+-ATPase activity of mouse spermatozoa. Also, SIF (250μgmL-1), when administered intravaginally in female BALB/c mice before mating, showed 100% contraceptive effect. Moreover, fluorescein isothiocyanate-labelled SIF was also found to bind mouse spermatozoa and various motile as well as non-motile bacteria, indicating the presence of common SIF-binding receptors on spermatozoa and bacteria. Further, to demonstrate molecular mimicry, the amelioration of SIF-induced impairment of sperm function by a SIF-binding bacterial receptor was compelling. For this, the SIF-binding receptor from Escherichia coli (E-SBR) was purified and evaluated for its ameliorative effect on SIF-induced sperm impairment invitro and invivo. Interestingly, upon the addition of mouse spermatozoa to SIF pre-incubated with E-SBR, an ameliorative effect against SIF-induced impairment of sperm function could be observed through analysis of normal sperm parameters (motility, viability, morphology, Mg2+-dependent ATPase levels). E-SBR also blocked binding of labelled SIF to spermatozoa and bacteria and alleviated SIF-induced infertility in female BALB/c mice. This provided evidence for molecular similarities between bacteria and spermatozoa, owing to which anti-bacterial antibodies cross-reacting with spermatozoa might be produced and infertility might follow.

Fluid resuscitation via the rectum ameliorates hemodynamic disorders through adjusting aquaporin expression in an experimental severe acute pancreatitis model

Acute pancreatitis is an acute abdominal disease, with 10-20% of the cases deteriorating rapidly, accompanied by persistent organ failure and further development into severe acute pancreatitis (SAP). The aim of the present study was to investigate the mechanism of fluid resuscitation via the rectum in the early stages of SAP and the role of aquaporins (AQPs). An SAP model was constructed by injection of 5% sterile sodium taurocholate into the biliopancreatic duct of Sprague Dawley rats, and the mean arterial pressure (MAP) was continuously monitored via femoral artery catheterization. At 30 min after the construction of the SAP model, the rats in the fluid resuscitation groups were resuscitated with normal saline at a rate of 4 ml/kg/h through the venous or the rectal route. The AQP and Na+-K+-ATPase levels, and the correlation of the MAP and colon AQPs at the early stages of SAP were analyzed. The results demonstrated that the mRNA level of AQP-3 and AQP-4 in the distal colon decreased significantly in the group subjected to fluid resuscitation via the rectum, while no significant differences were identified in the Na+-K+-ATPase levels of the colon in that group. Furthermore, a negative correlation was identified between the expression of AQPs and the MAP (P<0.01). Thus, fluid resuscitation via the rectum appears to ameliorate hemodynamic disorders through adjusting the expression of AQP-3 and AQP-4 in the distal colon in an experimental SAP model.

Chronic inhibition of nitric oxide synthase modulates calcium handling in rat heart 1.

Systemic infusion of nitric oxide synthase (NOS) inhibitors increases peripheral vascular resistance due to inhibition of endothelial NOS leading to the activation of the arterial baroreceptor mechanisms and inhibition of central sympathetic outflow. In the current study, we explored that systemic NOS blockage activates protein kinase A (PKA)-mediated signaling pathway through maintained cGMP-dependent protein kinase (PKG) activation. Rats were treated with 3 different concentrations of N(ω)-nitro-l-arginine methyl ester (L-NAME) for 14 days. Systemic L-NAME treatment induced a dose-dependent increase in blood pressure and increased mRNA levels of atrial natriuretic peptide (ANP) and phosphorylation levels of p44/42 MAPK without any change in cardiac mass. The cardiac cGMP levels and PKG-mediated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) (Ser239) did not alter in any group. At the highest dose of treatment (100 mg/kg per day), PKA-mediated phosphorylations of VASP (Ser157) and troponin I (TnI) (Ser23/24) were enhanced significantly indicating the increase in PKA activation in response to chronic NOS blockage. Alterations in both phosphorylated phospholamban (Ser16/Thr17) and sarcoplasmic/endoplasmic Ca2+-ATPase (SERCA2) levels can increase cytosolic Ca2+ load and impair Ca2+ handling. Our data suggest that the increased PKA activation in response to chronic NOS blockage appears to be responsible for cardiac abnormalities that occur due to prolonged L-NAME treatment.

Methanol extracts from Delonix regia leaves modulate apoptosis in cisplatin-induced nephrotoxicity in male rats

The incidence and prevalence of kidney failure has been on the increase in recent times and in addressing the global burden, the present study investigated the influence of methanol extract of Delonix regia (DR) leaves on rat models intraperitoneally injected with a single dose of 5 mg/kg cisplatin to induce nephrotoxicity. Cisplatin-induced nephrotoxic rats received daily oral gavage of either DR of 20 mg/kg, 50 mg/kg or 100 mg/kg for 10 days. On day 10, the levels of kidney mitochondrial ATPase (mATPase), lipid peroxidation (LPO), blood urea nitrogen (BUN) and plasma creatinine (CRE) were determined by spectrophotometry. The presence of cytochrome c and caspase 3 were determined immuohistochemically. Treatment with 20, 50 and 100 mg/kg showed a statistically significant reduction in the levels of BUN and CRE (p 50 > 20 mg/kg respectively (p < 0.05). The excessive release of cytochrome c and activation of caspase 3 observed in cisplatin-induced nephrotoxic rats were reduced by all treatment groups. The histologic findings revealed that cisplatin-induced nephrotoxic rats had disseminated infiltration of the renal cortex by inflammatory cells while treatment showed regenerated tubules. The suppression of mATPase activity, reduced release of cytochrome c and caspase 3 activation by Delonix regia could be a mechanism at least in part for its use in folklore medicine in the treatment of kidney disease.

Microgravity induces autophagy via mitochondrial dysfunction in human Hodgkin\u2019s lymphoma cells

Gravitational forces can impose physical stresses on the human body as it functions to maintain homeostasis. It has been reported that astronauts exposed to microgravity experience altered biological functions and many subsequent studies on the effects of microgravity have therefore been conducted. However, the anticancer mechanisms of simulated microgravity remain unclear. We previously showed that the proliferation of human Hodgkin’s lymphoma (HL) cells was inhibited when these cells were cultured in time-averaged simulated microgravity (taSMG). In the present study, we investigated whether taSMG produced an anticancer effect. Exposure of human HL cells to taSMG for 2 days increased their reactive oxygen species (ROS) production and NADPH oxidase family gene expression, while mitochondrial mass, ATPase, ATP synthase, and intracellular ATP levels were decreased. Furthermore, human HL cells exposed to taSMG underwent autophagy via AMPK/Akt/mTOR and MAPK pathway modulation; such autophagy was inhibited by the ROS scavenger N-acetylcysteine (NAC). These results suggest an innovative therapeutic approach to HL that is markedly different from conventional chemotherapy and radiotherapy.

Protective effects of Polygonatum sibiricum polysaccharide on acute heart failure in rats 1.

To investigate the protective effects of Polygonatum sibiricum polysaccharide (PSP) on acute heart failure (AHF) in rats. Sixty rats were randomly divided into control, model, and low-, middle- and high-dose PSP groups, 12 rats in each group. The low-, medium- and high-dose PSP groups were intragastrically administrated with 100, 200 and 400 mg/kg PSP for 5 days, respectively. On the sixth day, the AHF model was established by intraperitoneal injection of adriamycin. After 24h, the cardiac function, serum biochemical indexes, myocardial ATPase and succinate dehydrogenase levels and apoptosis related protein expressions were determined. Compared with model group, in high-dose PSP group the heart rate, left ventricular systolic pressure, ±dp/dtmax, serum superoxide dismutase level, myocardial Na+-K+-ATPase, Ca2+-Mg2+-ATPase and succinate dehydrogenase levels and myocardial Bcl-2 and Caspase-3 protein expression levels were significantly increased (P<0.05), the left ventricular end diastolic pressure, serum cTnI, CK-MB, TNF-α, IL-6, malondialdehyde and nitric oxide levels and myocardial Bax and cleaved Caspase-3 protein expression levels were significantly decreased (P<0.05). Polysaccharide can prevent the acute heart failure induced by adriamycin. The mechanism may be related to its anti-oxidative stress, anti-inflammation and inhibition of cardiac myocyte apoptosis.

Efficient iron plaque formation on tea (Camellia sinensis) roots contributes to acidic stress tolerance.

Tea plants grow in acidic soil, but to date, their intrinsic mechanisms of acidic stress tolerance have not been elucidated. Here, we assessed the tea plant response to growth on NH4 + nutrient media having different pH and iron levels. When grown in standard NH4 + nutrient solution (iron insufficient, 0.35 mg L-1 Fe2+ ), tea roots exhibited significantly lower nitrogen accumulation, plasma membrane H+ -ATPase activity, and protein levels; net H+ efflux was lower at pH 4.0 and 5.0 than at pH 6.0. Addition of 30 mg L-1 Fe2+ (iron sufficient, mimicking normal soil Fe2+ concentrations) to the NH4 + nutrient solution led to more efficient iron plaque formation on roots and increased root plasma membrane H+ -ATPase levels and activities at pH 4.0 and 5.0, compared to the pH 6.0 condition. Furthermore, plants grown at pH 4.0 and 5.0, with sufficient iron, exhibited significantly higher nitrogen accumulation than those grown at pH 6.0. Together, these results support the hypothesis that efficient iron plaque formation, on tea roots, is important for acidic stress tolerance. Furthermore, our findings establish that efficient iron plaque formation is linked to increased levels and activities of the tea root plasma membrane H+ -ATPase, under low pH conditions.

Early calcium handling imbalance in pressure overload-induced heart failure with nearly normal left ventricular ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a common clinical syndrome associated with high morbidity and mortality. Therapeutic options are limited due to a lack of knowledge of the pathology and its evolution. We investigated the cellular phenotype and Ca2+ handling in hearts recapitulating HFpEF criteria. HFpEF was induced in a portion of male Wistar rats four weeks after abdominal aortic banding. These animals had nearly normal ejection fraction and presented elevated blood pressure, lung congestion, concentric hypertrophy, increased LV mass, wall stiffness, impaired active relaxation and passive filling of the left ventricle, enlarged left atrium, and cardiomyocyte hypertrophy. Left ventricular cell contraction was stronger and the Ca2+ transient larger. Ca2+ cycling was modified with a RyR2 mediated Ca2+ leak from the sarcoplasmic reticulum and impaired Ca2+ extrusion through the Sodium/Calcium exchanger (NCX), which promoted an increase in diastolic Ca2+. The Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA2a) and NCX protein levels were unchanged. The phospholamban (PLN) to SERCA2a ratio was augmented in favor of an inhibitory effect on the SERCA2a activity. Conversely, PLN phosphorylation at the calmodulin-dependent kinase II (CaMKII)-specific site (PLN-Thr17), which promotes SERCA2A activity, was increased as well, suggesting an adaptive compensation of Ca2+ cycling. Altogether our findings show that cardiac remodeling in hearts with a HFpEF status differs from that known for heart failure with reduced ejection fraction. These data also underscore the interdependence between systolic and diastolic “adaptations” of Ca2+ cycling with complex compensative interactions between Ca2+ handling partner and regulatory proteins.

Effects of Pinocembrin Pretreatment on Connexin 43 (Cx43) Protein Expression After Rat Myocardial Ischemia-Reperfusion and Cardiac Arrhythmia.

BackgroundCardiac infarction frequently leads to arrhythmia and ischemia/reperfusion (I/R) aggravates cardiac injury. Pinocembrin can resist cerebral ischemia and decrease cardiac infarction area. This study thus generated a rat myocardial I/R model to assess the effect on ventricular rhythm and expression of gap junction connexin (Cx43).Material/MethodsMale SD rats were randomly assigned into sham, model, and pinocembrin (30 mg/kg) pretreatment groups (N=15 each). The I/R model was generated by ligation of the left anterior descending coronary artery for 30 min. The pinocembrin group received intravenous injection 10 min before surgery. Heart rate (HR), mean artery pressure (MAP), rate pressure product (RPP), and arrhythmia were observed at 10 min before ischemia, 30 min after ischemia, and at 30, 60, and 120 min after reperfusion. ELISA was used to assess serum CK-MB and cTnI levels. Na+-K+ATPase and Ca+-Mg2+ATPase levels were quantified by spectrometry, followed by HE staining, IHC approach for Cx43 expression, and Western blot for Kir2.1 protein expression.ResultsModel rats had significantly lower HR, MAP, and RPP than in the sham group, and the pinocembrin pretreatment group had higher serum indexes. Arrhythmia index, CK-MB, and cTnI were higher in the model and pinocembrin groups, while Na+-K+ATPase, Ca+-Mg2+ATPase, Cx43, and Kir2.1 proteins were lower (p<0.05).ConclusionsPinocembrin alleviated ventricular arrhythmia in I/R rats via enhancing Na+-K+ATPase and Ca+-Mg2+ATPase activity and upregulating Cx43 and Kir2.1 protein expression.

Grape seed proanthocyanidin extract supplementation affects exhaustive exercise-induced fatigue in mice.

BackgroundGrape seed proanthocyanidin extract (GSPE) has been extensively reported to possess a wide range of beneficial properties in multiple tissue damage. Previous studies have shown that exhaustive exercise-induced fatigue associates with oxidative stress injury, inflammatory response, and mitochondrial dysfunction.ObjectiveThe aim of this study is to investigate the anti-fatigue effects of GSPE in mice and explore its possible underlying mechanism.DesignThe mouse model of exhaustive exercise-induced fatigue was established by using the forced swimming test, and GSPE was orally treated for successive 28 days at 0, 1, 50 and 100 mg/kg/day of body weight, designated the control, GSPE-L, GSPE-M and GSPE-H groups, respectively.ResultsThe presented results showed that treatment of GSPE at a dose of 50 and 100 mg/kg/day of body weight significantly relieved exhaustive exercise-induced fatigue, indicated by increasing the forced swimming time. In addition, treatment of GSPE significantly improved the creatine phosphokinase and lactic dehydrogenase, as well as lactic acid level in exhaustive swimming. For underlying mechanisms, treatment of GSPE had anti-fatigue effects by promoting antioxidant ability and resisting oxidative effect, as represented by increased total antioxidative capability levels, enhanced superoxide dismutase and catalase activities, and ameliorated malondialdehyde levels. Furthermore, treatment of GSPE significantly inhibited the activity of tumor necrosis factor-α and interleukin-1β, which suggested that its protective effects on exhaustive exercise-induced fatigue may be attributed to inhibition of inflammatory response. Last but not the least, treatment of GSPE significantly improved succinate dehydrogenase and Na+-K+-ATPase levels to enhance mitochondrial function during exhaustive swimming-induced fatigue.ConclusionsThese results proved that treatment of GSPE possessed the beneficial properties of anti-inflammatory, antioxidant, and mitochondrial protection to improve exhaustive exercise, which suggested that GSPE could be used as an effective functional food to delay fatigue.