Changes of BAEP,NO contents and Na+-K+ATPase activities in brain tissues in rats with hyperbilirubinemia

AIM: To explore the roles of brain-stem auditory evoked potential (BAEP) in early monitoring the hearing loss and brain damages in hyperbilirubinemia and nitric oxide(NO) in the pathogenesis of bilirubin-induced hearing loss and brain damages. METHODS: Different doses of bilirubin solution (30 mg/kg, 60 mg/kg, 90 mg/kg, 120 mg/kg and 150 mg/kg) were injected into the abdominal cavity of 15-day old SD rats to make the animal model of hyperbilirubinemia. The serum concentrations of bilirubin were detected by a micro-gauge. The bilirubin concentrations in the brain tissues were examined via a diazo method. The Na+-K+ATPase activities in the brain tissues were analyzed by rooting phosphorus. The NO contents in the brain tissues were assayed via the method of nitrate reductase. BAEP were recorded with an evoked potential recorder. RESULTS: After making the ejection, parts of the rats in the high dosage groups (120 mg/kg and 150 mg/kg) showed the abnormal neuro-behaviors. After 6 hours of the ejection, the bilirubin concentrations in serum and in brain tissues, and NO contents in the brain tissues were increased significantly. The Na+-K+ATPase activities in the brain tissues were decreased obviously, and the PL and IPL of BAEP were prolonged significantly in all the experimental rats except the ones in low dosage group (30 mg/kg). The changes of them were closely related to the dose of injected bilirubin. CONCLUSION: The PL and IPL of BAEP are the objective and sensitive indexes for early monitoring the hearing loss and brain damages in hyperbilirubinemia. NO may plays a certain role in the pathogenesis of bilirubin induced hearing loss and brain damages.     

Changes in amino acid neurotransmitters during cerebral ischemia and reperfusion in awake rats

AIM: To study the dynamic changes of amino acid neurotransmitters during cerebral ischemia and reperfusion in awake rats. METHODS: Model of cerebral ischemia and reperfusion in awake rats was replicated. Glutamate (Glu), aspartate (Asp), γ-aminobutyric acid (GABA), glycine (Gly), taurine (Tau), alanine (Ala), serine (Ser), threonine (Thr) and glutamine (Gln) concentrations were measured with microdialysis, and excitotoxic index (EI) was calculated in dialysates of hippocampus, neo-cortex and striatum. RESULTS: The significant increases in extracellular not only excitatory amino acid neurotransmitters-Glu and Asp, and their neuromodulator-Gly, but also inhibitory amino acid neurotransmitter-GABA and its neuromodulator-Tau and Ala were observed. However, the EI, representing the balance of excitatory and inhibitory neurotransmitters, was significantly increased during ischemia. CONCLUSION: The results suggest that the elevated Glu and Asp levels during ischemia are insufficient to independently engender ischemic damage, and other neurotransmitters or other factors may play an important role in modulating the excitotoxic effects of Glu and Asp.     

Effects of panax notoginseng saponins on malondialdehyde content of the brain following brain injury in rabbits

AIM: To study the protective effect of panax notoginseng saponins (PNS) on brain in experimental brain injury. RESULTS:The MDA in the brain tissue following brain injury significantly increased, which related to the degree of brain edema; PNS dramatically decreased MDA in the brain tissue following brain injury and can alleviate the neuron ultrastructures damage.CONCLUSION:The inhibition of injury induced MDA increasing in the brain tissue by PNS may contribute to its overall neuroprotective action.     

Changes of neuropeptides and electrolytes in patients with acute traumatic brain injury

AIM: To investigate the levels of neuropeptides and electrolytes in the patients with acute traumatic brain injury.METHODS: Seventy-eight patients with acute brain injury were divided into mild, moderate and severe groups according to their GCS scores. The serum levels of arginine vasopressin (AVP) and angiotensin II (Ang II) were measured on day 1, 3 and 7 after injury. The serum levels of electrolytes were also measured on day 1. Forty-one subjects who received healthy check-up served as normalcontrols. RESULTS: Compared with normal control group, the serum levels of AVP and Ang II significantly increased in the patients with traumatic brain injury (P<0.01), depending on the severity of brain injury. Both neuropeptides reached the peak on day 3 after injury. The concentrations of serum potassium and calcium decreased in the patients with acute brain injury(P<0.01),also showing a severity-dependent tendency. No significant change of serum sodium in the patients with brain injury was observed. CONCLUSION: The serum levels of arginine vasopressin and angiotensin II canalso be used as the severity indicators of traumatic brain injuries. Decrease in serum potassium and calcium can also be used to evaluate the severity in patients with acute traumatic brain injury.     

Changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy

AIM: To investigate the changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy. METHODS: Ventricular hypertrophy was induced by a partial constriction of the abdominal aorta in rabbits. Myocytes were isolated by a two steps enzymological method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from other region (midmyocardium, Mid) with a razor. Whole cell patch clamp technique was used to record the action potential and ion currents. RESULTS: The action potentials duration at 90% repolarization (APD₉₀) of Epi, Mid and Endo were all prolonged significantly in hypertrophy group compared to control group. This prolongation of APD₉₀ was more pronounced in Mid (26.0%±2.7%) than that in Epi (14.0%±1.6%) and Endo (10.0%±1.1%). The transmural repolarization heterogeneity was increased significantly in the hypertrophy group. The I_Ks and I_to density in Epi, Mid and Endo was decreased significantly in hypertrophy group compared to those in control group. This decrease in I_Ks and I_to density was more pronounced in Mid than in Epi and Endo. No significantly difference of I_Ca,L and I_Kr density between hypertrophy group and control group in three layers was observed. The I_K1 density decreased significantly in hypertrophy group compared to control group, but the extent of the decrease had no differences among the three layers. CONCLUSIONS: The transmural repolarization heterogeneity increases significantly in rabbit hypertrophied ventricle. The decrease in transmural heterogeneity of I_to and I_Ks is the main causes.     

Serum concentration of S100-B protein in patients during CABG with or without cardiopulmonary bypass

AIM: To investigate the mutative law of the serum S100-B protein in patients undergone coronary artery bypass grafting with or without cardiopulmonary bypass (CPB-CABG or non-CPB CABG), and to compare the degree of cerebral injury in patients during CABG between the two different surgical manipulations.METHODS: 30 patients were divided into two groups: CPB-CABG group (group A) and non-CPB CABG group (group B). Every group included 15 patients. Blood from jugular vein was phlebotomized in every patients at the following 8 time points: before operation (OP), after anaesthesia, end of grafting, end of OP, 2 h after OP, 6 h after OP, 12 h after OP and 24 h after OP. The serum concentrations of S100-B protein in the samples were measured.RESULTS: The level of serum S100-B protein increased markedly at the beginning of CABG, and the peak value of group A (2.32 μg/L±0.26 μg/L) was treble higher than that in the patients in group B (0.71 μg/L±0.14 μg/L). The levels of S100-B protein tend to normal level in both groups 24 h after OP. The level of S100-B protein had notable relation with the time of CABG in group A and the manipulative time on the heart in group B.CONCLUSION: The degree of cerebral damage can be valued by investigating the mutative law of the serum S100-B protein in patients undergone CPB-CABG and non-CPB CABG. The non-CPB CABG reduces the degree of cerebral damage and avoids the functional disorder of central nerve.     

Changes of ［Ca2+］i and the activity of ACE in alveolar macrophages of rabbits with high-fat diet

AIM: To investigate the effects of high-fat diet on the level of intracellular free calcium (［Ca²⁺］_i) and the activity of angiotensinⅠconverting enzyme (ACE) in alveolar macrophages (AMs) of rabbits.The association between asthma and high-fat diet was also observed.METHODS: Twelve male New Zealand rabbits were medially divided into normal diet group and 1.2% high-cholesterol diet group randomly.8 weeks later,bronchial alveolar lavage was performed in vitro.［Ca²⁺］_i was determined by Fluo-2/am.The activity of ACE was detected with ultraviolet method.RESULTS: The levels of ［Ca²⁺］_i in AMs greatly increased (P＜0.01).The activity of ACE both in BALF and in culture supernatants of AMs was all greatly increased compared with normal diet group (P＜0.01).In hypercholesterolemic group the number of macrophages in BALF showed a positive correlation with the content of cholesterol in serum,such as the level of ［Ca²⁺］_i in AMs and the activity of ACE in the culture supernatants of AMs (all P＜0.05).CONCLUSION: The results suggest that AMs of rabbits may be activated by hyperlipoidemia and become ease to be stimulated.     

Changes and significance of ATPase and free radical in aged rats with brain ischemia-reperfusion

AIM: To study the mechanism of brain ischemia-reperfusion injury from ATPase activity and free radical metabolism in aged rats. METHODS: The young rats (5 months) and the aged rats (more than 20 months) were divided into young control group(YCG), young model group(YMG), aged control group(ACG) and aged model group(AMG). The ATPase and SOD activities and the contents of MDA, Ca^2＋, Na^＋ and K^＋ were measured in the rats with 30 min brain ischemia followed by 60 min reperfusion. RESULTS: The Ca^2＋content in the AMG was higher than that in the YMG and the ACG. The Na^＋-K^＋-ATPase activity in the ACG was lower than that in the YCG,was lower in the AMG than that in the YMG. The Ca^2＋-ATPase activities in the YCG was higher than that in the ACG, was lower in the AMG than that in the YMG and was higher than the ACG's. The serum and brain tissue SOD activities in the ACG was lower than that in the YCG, was lower in the AMG than YMG 's. The serum and brain tissue MDA/SOD ratio in the AMG was higher than that in the ACG.CONCLUSION:The brain tissue ischemia-reperfusion injury was related with calcium overload and free radical injury.The pathological changes were obvious and had some characteristics in the aged rats compared with the young rats because of the brain t issue aging changes in ATPase,calcium content and free radical metabolism in the aged rats.