ABSTRACT
BACKGROUND: Excessive nitric oxide (NO) release can cause the occurrence and development of brain injury and senile dementia due to the apoptosis induction role of NO at high concentration to nerve cells. Therefore one strategy to prevent and treat senile dementia is inhibiting the apoptosis induced by NO.OBJECTIVE: To observe whether acidic peptide will inhibit the neuron apoptosis caused by NO. DESIGN: An cell and molecule observation experiment by comparisons. SETTING: Department of Biochemistry and Molecular Biology of Basic Medical College in Zhengzhou University and the Second Laboratory of Biological Active Peptide Institute in Zhengzhou University. MATERTALS: The experiment was performed between May 2003 and May 2005, in the Second Laboratory of Biological Active Peptide Institute in Zhengzhou University and the cell culture room of Department of Biochemistry and Molecular Biology of Basic Medical College in Zhengzhou University. The newborn SD male rats within 24 hours after birth were provided by the Animal Center of Henan Province (410117).METHODS: On day 11 of primary cultures, hippocampus neurons of the newborn SD rats were pretreated with different dosages of acidic peptide for six hours. Sodium nitroprusside (SNP) of 50 μmol/L final concentration was added to the cells which were incubated for another 24 hours. Cells were collected and adopted in this experiment of five different groups, namely normal control group, group treated with SNP, group of SNP plus 0.037 5 mg/mL acidic peptide, group of SNP plus 0.075 mg/mL acidic peptide, group of SNP plus 0.15 mg/mL acidic peptide. The cell's survival rate wasmeasure by methyl thiazolyl (MTT) method; The neurofilament protein was stained with the method of immunohisto chemistry. The shape of apoptosis was display with acridine orange fluorescent stain. Then DNA ladder zone of apoptosis cells was analyzed with the method of agarose gel electrophoresis. Western Blot and absorbance scan were used to determine the expression level of Bcl-2 protein and Bax protein.MAIN OUTCOME MEASURES: ①Experimental result of cell survival rate with MTT method;②Observation results of nuclear type of apoptosis; ③DNA electrophoresis analysis of apoptosis; ④Western Blot analysis results of Bcl-2 protein and Bax protein.RESULTS: ①Neuron survival rate was 58.9％ for group treated with SNP, 70.0％ for group of SNP plus 0.037 mg/mL acidic peptide, 72.8％ for group of SNP plus 0.075 mg/mL acidic peptide, and 75.3％ for group of SNP plus 0.15 mg/mL acidic peptide. ②Observation results of nuclear type of apoptosis: Significant characteristics of apoptosis were seen in group treated with SNP. The nucleus of hippocampus neuron treated with different concentrations of acidic peptide plus SNP was similar to that of normal control group in morphology. ③The results of DNA electrophoresis analysis of apoptosis: Only the neuron DNA of group treated with SNP showed clear characteristic DNA ladder zone of apoptosis on agarose gel electrophoresis. ④Analysis results of Bcl-2 protein and Bax protein with Western Blot and absorbance scan: The expression level of Bcl-2 protein in SNP treated group was decreased while that of Bcl-2 protein was increased. Bcl2 protein levels in acidic peptide plus SNP group were increased and Bax protein levels were decreased gradually with the increasing concentrations of acidic peptide compared with SNP treated group. CONCLUSION: Acidic peptide can inhibit neuron apoptosis, increase expression level of neuron Bcl-2 protein and decrease expression level of neuron Bax protein.
ABSTRACT
BACKGROUND: Acidic peptide is the tripeptide composed of 3 glutamic acids, which cannot bring excitatory nerve signal transmission into playlike single glutamic acid through presynaptic release and integration withpostsynaptic NMDA receptor directly as excitable neurotransmitter. It is quite possible that acidic peptide plays its actions by integrating with multiple metabolic glutamic acidic receptors so as to promote neuron proliferation or release nerve growth factor (NGF). OBJECTIVE: To probe into whether acidic peptide induces changes in learning and memory of model rats with Alzheimer disease (AD).DESIGN: Randomized controlled single experiment was designed.SETTING: Teaching-Research Room of Biochemistry and Molecular Biology of Basic Medical College of Zhengzhou University.MATERIALS: The experiment was performed in 2nd Research Room and Experimental Animal Room of Teaching-Research Room of Biochemistry and Molecular Biology of Basic Medical College of Zhengzhou University.Totally 100 SD male rats were selected and some of them were excluded due to retarded response in step down test. Totally 84 rats were included in the experiment and randomized into 7 groups, named normal control,model group, physiological saline group (PS group), piracetam group, acidic peptide groups of 60, 30 and 15 mg/kg, 12 rats in each group. Acidic peptide is a new small molecular peptide separated from bovine brain in this research team and is tripeptide composed of three glutamic acids.METHODS: Except normal control, in the rest groups, after 1 week routine breeding, cerebral stereotactic microinjection was used to inject 5 μg ibotenic acid in hippocampus of rats to destroy bilateral Meynert's basal ganglia to establish AD model. In normal control and model group, no medication was applied. In PS group, physiological saline was used for gastric perfusion. In piracetam group, piracetam of 0.3 g/kg was used for gastric perfusion and in acidic peptide groups of 15, 30 and 60 mg/kg,acidic peptide of 60, 30 and 15 mg/kg was applied for gastric perfusion successively, continuously for 20 days, once per day, 2 mL/time. On the expiration of gastric perfusion, learning and memory of rats were examined with step down test in every group. The animal was placed on the safe table on step down platform to adapt to the environment for 3 minutes, afterwards, 36 V electric current was given. Error response was recorded if the animal jumped to the copper railings after electric shock and correct response was recorded if the animal jumped back the safe area. Step-up latent phase and frequency of correct response were recorded in 3 minutes.MAIN OUTCOME MEASURES: Comparison of learning and memory of rats in every group. RESULTS: Totally 84 rats were all included in the result analysis. ①Comparison of learning in every group: Compared with model group, stepup latent phase was shortened remarkably in every acidic peptide group[(102.03±5.33), (71.77±4.38), (68.28±9.53), (69.13±8.79) s, P ＜ 0.01] and the frequency of correct response was improved remarkably [(12.92±2.91),(16.17±2.79), (15.83±3.27), (16.33±2.53) times, P ＜ 0.01]. ② Comparison of memory in every group: Compared with model group, step-up latent phase was shortened remarkably in every acidic peptide group [(43.17±4.66),(29.78±4.48), (26.20±3.28), (22.09±4.43) s, P ＜ 0.01] and the frequency of correct response was improved remarkably [(15.67±2.15), (20.92±2.68),(20.83±2.29), (20.25±2.05) times, P ＜ 0.01].CONCLUSION: Acidic peptide can shorten remarkably the step-up latent phase of AD rats in step down test and improve the frequency of correct response. It is indicated that acidic peptide provides good intervention on learning and memory of rat model of Alzheimer disease.
ABSTRACT
BACKGROUND: It is pointed in some experiment that acidic peptide improves learning and memory of model rat with Alzheimer disease (AD) by inhibiting the synthesis of toxic compounds of nitric oxide (NO).OBJECTIVE: Animal model with Alzheimer disease was established to observe the changes in the levels of NO, nitric oxide synthase (NOS) and acetylcholinesterase (AChE) treated with acidic peptide of various dose concentration.DESIGN: Randomized control and single experiment.SETTING: Teaching-Research Room of Biochemistry and Molecular Biology of Basic Medical College of Zhengzhou University.MATERIALS: The experiment was performed in 2nd Research Room and Experimental Animal Room of Teaching-Research Room of Biochemistry and Molecular Biology of Basic Medical College of Zhengzhou University.Totally 100 SD male rats were selected and some of them were excluded due to retarded response in step down test. Totally 84 rats were included in the experiment and randomized into 7 groups, named normal control,model group, physiological saline group (PS group), Piracetam group, acidic peptide groups of 15, 30 and 60 mg/kg, 12 rats in each group. Acidic peptide was a new small molecular peptide separated from bovine brain and is tripeptide composed of three glutamic acids.METHODS: Except normal control, in the rest groups, after 1 week routine breeding, cerebral stereotactic microinjection was used to inject 5 μg ibotenic acid in hippocampus of rats to destroy bilateral Meynert's nucleus basalis to establish AD model. In normal control and model group, no medication was applied. In PS group, physiological saline was used for gastric perfusion. In piracetam group, piracetam of 0.3 g/kg was used for gastric perfusion and in acidic peptide groupsof 15, 30 and 60 mg/kg,acidic peptide of 15, 30 and 60 mg/kg was applied for gastric perfusion successively, continuously for 20 days, once per day, 2 mL/time. On the expiration of gastric perfusion, the rats were sacrificed after anesthetized and the brain was collected on ice plate to prepare tissue homogenate. After centrifugated at 1 000 r/minute, 4℃ for 10 minutes, the supernatant was collected to assay the levels of NO, NOS and AChE with NO, NOS and AChE kits successively.MAIN OUTCOME MEASURES: Levels of NO, NOS and AChE in brain of rat in each groupRESULTS: Totally 84 rats were employed in the experiment and all entered result analysis. Comparison of levels of NO, NOS and AChE in rat brain of each group: compared with model group, NO levels in acidic peptide groups of 15, 30 and 60 mg/kg were reduced remarkably[(1.95±0.20), (1.39±0.10), (1.25±0.07), (1.00±0.04) mmoL/kg, P ＜ 0.05],NOS levels were reduced remarkably [(4.53±0.18), (3.39±0.09), (3.10±0.06),(2.97±0.06) μmol/kg, P ＜ 0.05] and AChE did not change remarkably[(0.67±0.12), (0.71±0.11), (0.72±0.08), (0.72±0.07) mmol/L, P ＞ 0.05].CONCLUSION: Acidic peptide reduces significantly the synthesis of NO and NOS in brain of AD rat, but it dose not affect AChE activity remarkably. It is suggested that acidic peptide improves learning and memory of rat with Alzheimer disease probably by inhibiting the synthesis of toxic compound of NO or its toxicity.
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Objective To study X-ray and CT diagnosis and Differential diagnosis of nonossifying fibroma.Methods 29 cases of nonossifying fibroma proved by pathology were included in this paper.29 cases underwent radiography and 12 cases underwent CT scan.There were 22 male and 7 female,with age ranged from 5~59 years(mean age 21.3 years),X-ray and CT findings of tumors were analysed.Results The tumors were located in long bone in 27 cases,in which 17 cases were located in metaphses,2 cases in diaphyses,8 cases in bone end and 2 cases in irregular bone.The maximum diameter of tumors ranged from 0.5~7 cm.The tumors were round,oral or mild lobular in 21 cases,the tumors were showed sclerotic borders in 26 cases.Septum was demonstrated in 22 cases on X-ray plain films,but only 2 cases on CT.Bone expansion was showed in 13 cases.Conclusion Most of nonssifying fibroma have characteristic X-ray and CT findings,the diagnosis be identified by X-ray and CT before operation.
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Objective To analyze X-ray plain film and CT signs of giant cell tumor of bone.Methods Imaging findings of giant cell tumor in 53 cases proved surgically and pathologically were retrospectively analyzed.Results 39 cases appeared as expensive cystic and eccentric destruction,osteolytic destruction 14 cases.Bone crests were usually seen in (39/53).Most of lesions did not have bone septations on CT image.The borders of destructive bone were clear and existed complete or incomplete sclerotic borders in 19 on CT image.The inner soft tissues of lesions were heterogeneous in most of the cases.Fluid-fluid level could be seen in 11 cases.The soft tissue masses outside the bone were demonstrated in the majority cases with discontinuous bone shell.Conclusion CT is more helpful than X-ray plain films in diagnosis of giant cell tumor of bone.