Expression of NKCC1 and Na-K-ATPase in C57BL/6J mice with age-related hearing loss / 中国耳鼻咽喉头颈外科

OBJECTIVE Disturbance of K+ ion balance in inner ear is associated in age-related hearing loss. Our study is to investigate the role of NKCC1 and Na-K-ATPase in cochlea and auditory function regulated by with different expression of NKCC1 and Na-K-ATPase. METHODS Auditory threshold of young or old C57BL/6J mice was measured by auditory brainstem response(ABR). The expression of NKCC1 and Na-K-ATPase in mice cochlea were evaluated by reverse transcription polymerase chain reaction(RT-PCR) and western blotting. Furosemide and Ouabain were applied in vivo to inhibit NKCC1 and Na-K-ATPase in C57BL/6J mice. RESULTS C57BL/6J mice developed hearing loss at 12M by ABR threshold shifting to (75±10), (78±26) and (81±14)dB SPL at frequencies of 8, 16 and 32 kHz; PCR showed that the relative expression of NKCC1 and Na-K-ATPase mRNA in the aged group decreased, which were 0.52±0.06 and 0.35±0.04 times higher than those in the young control group, the difference was statistically significant(t =7.466 and 16.11, all P＜0.05). WB showed that relative expression of NKCC1 and Na-K-ATPase protein level in the aged group decreased by 0.79±0.02 and 0.68±0.05 times as much as that of the young control group, the difference was statistically significant(t =8.857 and 6.771, P all＜0.05). After applied with Furosemide and Ouabain to suppress the two ion transporters, the ABR threshold increased to (50±17), (53±21), (55±17)dB SPL and (56±6), (70±17), (73±6)dB SPL at frequencies of 8, 16 and 32 kHz. CONCLUSION In vivo experiment of C57BL/6J suggested that NKCC1 and Na-K-ATPase might be related to age related hearing loss.

Phenotypic and genotypic characteristics of fever-induced paroxysmal weakness and encephalopathy caused by ATP1A3 pathogenic variants / 中华儿科杂志

Objective@#To characterize fever-induced paroxysmal weakness and encephalopathy (FIPWE) caused by ATP1A3 gene pathogenic variant.@*Methods@#Phenotypic and genotypic characteristics of 4 FIPWE patients (3 boys and 1 girl), who were ascertained from October 2016 to March 2018 in Beijing Children's Hospital due to ATP1A3 heterozygous variants, were retrospectively analyzed. The whole exsome sequencing was used for genetic testing.@*Results@#The onset ages of 4 patients were 2 years and 9 months, 2 years and 4 months, 8 months, 2 years and 5 months respectively. The episode ranged from 1 to 3 times, and at 3 months to 2 years and 10 months intervals. All 4 patients had symptoms of limb weakness and encephalopathy, accompanied with mild to severe ataxia or athetosis. The tendon reflex was absent in all patients, and the Babinski's sign was positive. Three patients had dysphagia and 3 patients had slurred speech. Three patients had abnormal eye movements, including strabismus and opsoclonus. None of the 4 patients exhibited visual impairment, auditory impairment or talipes cavus. The duration of acute phase ranged from 1 week to 3 months. In 3 relapsing patients, symptoms became progressively worse, with relapses occurring frequently and recovery being more difficult, and various sequelae were found after the last relapse. All patients carried heterozygous variant in ATP1A3 gene. The missense variants result in the substitution of an arginine residue at position 756. Three variants were identified, including C. 2267G > T (p. R756L) (1 case), C. 2266C > T (p. R756C) (2 cases), and C. 2267G > A (p. R756H) (1 case). Three were de novo and one inherited from his father, but the grandparents did not carry the variant. All variants were reported as pathogenic.@*Conclusions@#FIPWE is one of new clinical phenotypes of ATP1A3 spectrum disease and most cases are sporadic. The missense variants result in the substitution of an arginine residue at position 756. This report provided insights into the phenotype-genotype association in patients with FIPWE caused by pathogenic variants of ATP1A3.

Effect of sevoflurane on activities of Na+-K+-ATPase and Ca2+-ATPase in hippocampus of diabetic rats / 中华麻醉学杂志

Objective To evaluate the effect of sevoflurane on activities of Na+-K+-ATPase and Ca2+-ATPase in the hippocampus of diabetic rats.Methods SPF healthy male Wistar rats,aged 8 weeks,weighing 180-200 g,were fed a high-fat diet for 3 consecutive weeks and streptozotocin was intraperitoneal-ly injected to induce type 2 diabetes mellitus.Forty-four rats with diabetes mellitus were divided into 2 groups (n=22 each) using a random number table:diabetic group (D group) and sevoflurane group (S group).Another 22 healthy Wistar rats,aged 8 weeks,weighing 180-200 g,served as control group (C group).Oxygen was inhaled for 2 h in C and D groups,and 2.4％ sevoflurane was inhaled for 2 h in S group.Eight rats were sacrificed at 30 min after treatment,brains were removed and hippocampi were isolated for measurement of Na+-K+-ATPase and Ca2+-ATPase activities in hippocampal tissues by spectrophotometry.Ten rats were randomly selected at 1 day after treatment,and Morris water maze test was performed to assess the cognitive function.Four rats were randomly sacrificed,brains were removed and hippocampi were isolated for examination of the mitochondrial ultrastructure with a transmission electron microscope.Results Compared with group C,the escape latency was significantly prolonged,the number of crossing the original platform was reduced,the percentage of time of staying at the original platform quadrant was decreased,the activities of Na+-K+-ATPase and Ca2+-ATPase in hippocampi were decreased (P＜ 0.05),and mitochondrial swelling and decreased mitochondrial cristae were observed under the electron microscope in group D.Compared with group D,the escape latency was significantly prolonged,the number of crossing the original platform was reduced,the percentage of time of staying at the original platform quadrant was decreased,the activities of Na+-K+-ATPase and Ca2+-ATPase in hippocampi were decreased (P＜ 0.05),and mitochondrial swelling and vacuolization were found under the electron microscope in group S.Conclusion The mechanism by which sevoflurane aggravates cognitive dysfunction is related to deceasing activities of Na+-K+-ATPase and Ca2+-ATPase in the hippocampus of diabetic rats.

The Effects of Altered Membrane Cholesterol Levels on Sodium Pump Activity in Subclinical Hypothyroidism

BACKGROUND: Metabolic dysfunctions characteristic of overt hypothyroidism (OH) start at the early stage of subclinical hypothyroidism (SCH). Na⁺/K⁺-ATPase (the sodium pump) is a transmembrane enzyme that plays a vital role in cellular activities in combination with membrane lipids. We evaluated the effects of early changes in thyroid hormone and membrane cholesterol on sodium pump activity in SCH and OH patients. METHODS: In 32 SCH patients, 35 OH patients, and 34 euthyroid patients, sodium pump activity and cholesterol levels in red blood cell membranes were measured. Serum thyroxine (T₄) and thyroid stimulating hormone (TSH) levels were measured using enzyme-linked immunosorbent assays. Differences in their mean values were analysed using post hoc analysis of variance. We assessed the dependence of the sodium pump on other metabolites by multiple regression analysis. RESULTS: Sodium pump activity and membrane cholesterol were lower in both hypothyroid groups than in control group, OH group exhibiting lower values than SCH group. In SCH group, sodium pump activity showed a significant direct dependence on membrane cholesterol with an inverse relationship with serum TSH levels. In OH group, sodium pump activity depended directly on membrane cholesterol and serum T4 levels. No dependence on serum cholesterol was observed in either case. CONCLUSION: Despite the presence of elevated serum cholesterol in hypothyroidism, membrane cholesterol contributed significantly to maintain sodium pump activity in the cells. A critical reduction in membrane cholesterol levels heralds compromised enzyme activity, even in the early stage of hypothyroidism, and this can be predicted by elevated TSH levels alone, without any evident clinical manifestations.

Possible senescence associated change in the predominant &alpha -Na+/K+ ATP-ase isoform in the renal cortex of the rat

With aging the kidney exhibits progressive deterioration, with a decrease in renal function. Most of the filtered Na+ is actively reabsorbed in the proximal tubules through different transporters located in apical membrane. This process is possible because basolateral Na+/K+-ATP-ase generates electrochemical conditions necessary for energetically favorable Na+ transport. The α-subunit is the catalytic domain of Na+/K+-ATP-ase. There are three isoforms of the α/subunit present in rat kidney. The present study was undertaken to examine the expression pattern of rat α-Na+/K+-ATP-ase during senescence. We tested the impact of aging on mRNA expression of α-Na+/K+-ATP-ase in cortex and medulla of aged Wistar rats. We observed a significant expression decrease in mRNA levels and a possible change of isoform in the cortex of aged animals. These expression changes observed for αsubunit could be contributing to affect the renal function in conditions of water and salt stress.

Con el avance de la edad los riñones exhiben un deterioro funcional progresivo con disminución de la función renal. La mayor parte del sodio (Na+) filtrado es reabsorbido activamente en los túbulos proximales a través de diferentes transportadores ubicados en la membrana apical. Este proceso es posible por la existencia de la Na+/K+-ATP-asa basolateral, que genera las condiciones electroquímicas necesarias para que el transporte de Na+ sea energéticamente favorable. La subunidad αde la Na+/K+-ATP-asa es el dominio catalítico de la enzima. Existen tres isoformas de subunidad α, que están presentes en el riñón de la rata. En este trabajo se examinan los patrones de expresión de la α-Na+/K+-ATP-asa durante la senescencia. Se estudió así si el aumento de la edad incidía en la expresión del ARNm de la α-Na+/K+-ATP-asa en corteza y médula renal de ratas Wistar senescentes. Se observó una disminución en la expresión del ARNm de la subunidad αy un posible cambio de isoforma predominante en la corteza de los animales senescentes. Los cambios observados para la expresión de la subunidad αpodrían contribuir a afectar la función renal en condiciones de estrés hídrico y salino.

Aspectos clínicos, fisiopatológicos e genéticos das tubulopatias hereditárias na infância / Clinical, pathophysiological and genetic aspects of inherited tubular disorders in childhood

ResumoNesta revisão, descrevemos a função tubular de cada segmento do néfron seguida das descrições das principais alterações moleculares que possam ocorrer nos transportadores expressos nestes locais. Assim, o conhecimento das modificações na função tubular renal permite o entendimento e o reconhecimento clínico das doenças tubulares renais que podem causar a morte fetal, neonatal ou infantil. Além disso, as crianças com tubulopatias podem evoluir para doença renal crônica terminal numa fase precoce da vida e também podem apresentar distúrbios do crescimento e do desenvolvimento acompanhados ou não de alterações neurológicas. Então, nós utilizamos o unitermo "inherited tubular disorders" a fim de selecionar na base de dados do PubMed os estudos publicados desde 2006. Esperamos que a leitura desta revisão auxilie no rápido diagnóstico dos pacientes com tubulopatias, o que poderá permitir o tratamento especializado e a possível melhora do prognóstico e qualidade de vida destes indivíduos.

AbstractIn this review, we described the tubular function of each nephron segment followed by the most important changes that may occur in the transporters expressed therein. Thus, knowledge of the changes in renal tubular function allows the understanding and recognition of renal tubular diseases that can cause stillbirth or death in newborns or in childhood. Moreover, children with tubular disorders may progress to chronic renal disease at an early stage of life and they may also show disturbances of growth and development associate or not with neurological dysfunction. Therefore, we used the keyword "inherited tubular disorders" to select the children studies that have been published in the PubMed database since 2006. We hope that this review may help physicians to perform an early diagnosis in patients with tubular disorders allowing a specialized treatment and an improvement in their prognosis and quality of life.

Effects of percutaneous midband pulse current stimulation in hepatic region on the activity of hepatic mitochondrial Na+-K+-ATPase and Ca2+-Mg2+-ATPase in exercise-induced fatigued rats / 解放军医学杂志

Objective To explore the effects of percutaneous impulsive current stimulation in hepatic region on the activity of hepatic mitochondrial Na+-K+-ATPase and Ca2+-Mg2+-ATPase in exercise-induced fatigued rats, in order to investigate the effect of exercise-induced fatigue. Methods Seventy-two 8-week old male Wistar rats were randomly divided into 4 groups (18 each): control group (group A), fatigue group (group B), stimulation before fatigue group (group C) and stimulation after fatigue group (group D). Exhaustion of animals in B, C and D groups were reproduced by prolonged swimming. Current stimulation (1024Hz, 10mA, current cycle 1sec) for 20 minutes was given to the rats of group C before swimming, and to those in group D after exhaustion. At the weekend of 1st, 3rd and 5th week after modeling, the rats were sacrificed in batches from each group (6 each). The activities of hepatic mitochondrial Na+-K+-ATPase and Ca2+-Mg2+-ATPase were determined by spectrophotometry, and Bradfood protein quantification was employed to quantitate the protein in rats' hepatic mitochondria. Results No significant difference was found in swimming-exhaustion time among 3 groups at the first weekend (P>0.05), while the swimming-exhaustion time was significantly prolonged at the 3rd and 5th weekends in group D than in group B and C (P+-K+-ATPase and Ca2+-Mg2+-ATPase among the 4 groups (including group A) at the weekend of the 1st week (P>0.05), while the enzyme activities were obviously lower at the 3rd and 5th weekend in group B than that in groups A, C and D (P+-K+-ATPase and Ca2+-Mg2+-ATPase. Percutaneous pulsive current stimulating hepatic region of exercise-induced fatigued rats may improve the enzyme activity, reduce the concentration of free calcium and calcium overload in mitochondria, stimulate the oxidative phosphorylation, accelerate the rate of respiratory chain, promote exercise endurance and score, and relieve exercise-induced fatigue rapidly.

Na+ ,K+ -ATPase and cerebral ischemia / 国际脑血管病杂志

The basic functions of the Na+/K+ -ATPase is to maintain the balance of the Na+/K+ electrochemical gradient. The latter is indispensable for maintaining cell osmotic pressure,regulating cell volume,and maintaining excitable membrane resting potential. The maintenance of the Na+/K+ -ATPase activity plays the important roles in neurotransmitter uptake in neurons and Ca2+ effiux. The decreased Na+/K+ -ATPase activity and dysfunction participate in the process of ischemic brain injury after cerebral ischemia. Ischemic precondi-tioning induces ischemic tolerance by maintaining the Na+/K+ -ATPase activity after ischemia.Cardiotonic steroids and citicoline may play a neuroprotective effect on cerebral ischemia by improving the Na +/K+ -ATPase activity.

Effect of sevoflurane postconditioning on activities of Na+-K+-ATPase and Ca2+ -Mg2+ -ATPase during myocardial ischemia-reperfusion in rats / 中华麻醉学杂志

Objective To investigate the effect of sevoflurane postconditioning on the activities of Na+ -K+ -ATPase and Ca2+ -Mg2+ -ATPase during myocardial ischemia-reperfusion (I/R) in rats and the possible mechanism. Methods Forty-five healthy male Wistar rats weighing 250-280 g were randomly divided into 3 groups ( n = 15 each): sham operation group (group S), I/R group and sevoflurane postconditioning group (group Spo). Myocardial I/R was induced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min of reperfusion. In group S the anterior descending branch was only exposed but not ligated. Group Spo received 5 min inhlation of 2.5% sevoflurane 1 min before reperfusion. The myocardial tissues were taken at 2 h of reperfusion for determination of infarct size and activities of Na+ -K+ -ATPase and Ca2 * -Mg2 * -ATPase. Results The infarct size was significantly larger and the activities of Na+ -K+ -ATPase and Ca2+ -Mg2+ -ATPase were signifi cantly lower in group I/R than in group S ( P ＜ 0.05). The infarct size was significantly smaller and the activities of Na+ -K+ -ATPase and Ca2+ -Mg2+ -ATPase were significantly higher in group Spo than in group I/R (P ＜ 0.05 ). Conclusion Sevoflurane postconditioning can reduce myocardial I/R injury through increasing the activities of Na+ -K+ -ATPase and Ca2+ -Mg2+ -ATPase.