BACKGROUND: Studies show that proper exercise has the effect of anti-aging, increasing bone mass accumulation and reducing bone mass loss. OBJECTIVE: To investigate the effect of aerobic exercises on osseous composition In aging rats. DESIGN, TIME AND SETTING: A randomized control animal experiment was completed in the Animal Experiment Laboratory of Xi'an Sports Institute from April to June in 2007. MATERIALS: A total of 64 clean male SD rats weaned for 2 months were randomly divided into a normal control group, a non-modeling exercise group, an aging model group and a modeling exercise group, with 16 ones in each group. Every 8 rats of each group were sacrificed at the 6th and 9th week respectively.exercise for 6 and 9 weeks. MAIN OUTCOME MEASURES: At the end of week 6 and 9, rats in each group were detected regarding to the following measures: serum alkaline phosphatase, bone gla protein, serum propeptide of type] procollagen, serum total calcium, serum inorganic phosphorus, serum magnesium, urinary calcium, urinary inorganic phosphorus, urinary magnesium, urinary hydroxylysine glycoside. Bone trabecula changes in femoral bone tissue were observed with light microscope. RESULTS: Compared with the normal control group, the aging model group got a decrease at the following indexes at both week 6 and week 9, namely, serum alkaline phosphatase, serum propeptide of type Ⅰ procellagen, serum total calcium, serum magnesium, urinary calcium, urinary inorganic phosphorus, urinary hydroxyproline. While in the non-modeling exercise group and the modeling exercise group, these above-mentioned indexes increased. Compared with the normal control group, the aging model group got an increase at the following indexes at both week 6 and week 9, namely, serum osteocalcin, inorganic phosphorus, adnary magnesium, urinary hydroxylysine glycoside. While in the non-modeling exercise group and the modeling exercise group, these above-mentioned indexes decreased. In Addition, exercise of 9 weeks led to a better recovery result than that of 6 weeks. The detection under light microscope showed an obvious few bone trabeculas in the aging model group and an increase of bone trabeculas per unit volume in the non-modeling exercise group and the modeling exercise group. CONCLUSION: Aerobic exercise has a great effect on the morphosis of femoral bone osseous composition in aging rats, and it can delay osteoporosis.

BACKGROUND:N-methyl-D-aspartate receptor is an ionic glutamate receptor which is closely related with the neural synaptic plasticity, and also can regulate neural synaptic plasticity. OBJECTIVE:To explore the mechanism by which N-methyl-D-aspartate receptor subunits NR2A and NR2B regulate neural synaptic plasticity after cerebral ischemia. METHODS: 60 Wister rats were randomly and evenly divided into a sham-operated group and a cerebral ischemia group. Rat models of chronic cerebral ischemia were established using the modified bilateral common carotid artery occlusion method in the cerebral ischemia group, while rats in the sham-operated group did not undergo occlusion of the common carotid artery and vagus nerve. RESULTS AND CONCLUSION:At 0-12 hours after chronic cerebral ischemia, NR2A expression in the rat hippocampus was gradualy decreased, while the expression of NR2B reached its peak level at 4 hours after cerebral ischemia. Under the circumstance of cerebral ischemia, neither low frequency nor high frequency induced long-term potentiation. These findings suggest that NR2B exhibit inhibitory effect, while NR2A exhibit promoting effect on long-term potentiation induced by stimulation.

Objective To explore the teaching effects of Lecture Based Learning (LBL) incorporated with Case Based Learning (CBL) and Problem Based Learning (PBL) methods in the teach-ing of anatomy.Methods 740 students of Grades 2012 and 2013 from clinical medical major were chosen as the subjects,randomly divided into experimental and control groups.LBL was conducted in the control group of 644 students,while LBL+PBL+CBL method was applied in the experimental group of 96 students.After completion of the course,all students were surveyed with the questionnaire and tested with specimen and theoretical examinations.The data was collected and analyzed with SPSS 17.0 and two sample U tests.Results The students' time of learning anatomy in the control group outside classroom teaching was (105 ± 25) minutes per week,while the students' time of learning anatomy in the experimental group was (190 ± 25) minutes per week.The difference was statistically significant (t=31.08,P=0.000).The difference of after-class total learn-ing time was also statistically significant between two groups(t=27.42,P=0.000).Percentages of satisfaction with teaching methods for control group were 87.5％ and 87％,while for the experimental group 98％ and 100％.Kruskal-Wallis test showed there were significant differences in experimental groups of grades 2012(x2=31.19,P=0.000) and 2013 (x2=40.35,P=0.000) compared with control group.Comparison of both groups' results of the examinations was statistically significant concerning multiple choices,essays and case analysis questions (P＜0.05).Conclusion Teaching method of LBL incorporated with PBL and CBL was significantly effective than that of the sole traditional LBL method,which indicated its practice value.