Objective To evaluate the effect of stellate ganglion block (SGB) on postoperative synaptic structure in hippocampal CA3 region in aged rats.Methods Seventy-two male Sprague-Dawley rats,aged 20-22 months,weighing 550-650 g,were randomly divided into 3 groups (n =24 each) using a random number table:control group (group C),operation group (group O) and SGB + operation group (group SGB).Group SGB received right SGB with 0.25％ bupivacaine 0.15 ml.Groups O and SGB underwent 30 min of exploratory laparotomy starting from 15 min after the end of administration.Y-maze test was performed on 1 day after operation in 6 rats chosen from each group for assessment of cognitive function.The frequency of standard training and standard time were recorded.Six rats were chosen from each group on 1,3 and 7 days after operation and sacrificed and the hippocampal CA3 region was isolated for microscopic examination and for measurement of synaptic structure.Results Compared with group C,the standard time was significantly prolonged,and the frequency of standard training was increased in groups O and SGB,the width of synaptic cleft was increased,the thickness of post-synaptic density was decreased,the length of active zones was shortened,and the curvature of the synaptic interface was decreased on 1,3 and 7 days after operation in group O (P ＜ 0.05),and no significant changes were found in each synaptic structure parameter in group SGB (P ＞ 0.05).Compared with group O,the standard time was significantly shortened,the frequency of standard training was decreased,the width of synaptic cleft was decreased,the thickness of the post-synaptic density was increased,the length of active zones was prolonged,and the curvature of the synaptic interface was increased on 1,3 and 7 days after operation in group SGB (P ＜ 0.05).Conclusion The mechanism by which SGB improves the postoperative cognitive dysfunction in aged rats may be related to inhibition of changes of synaptic structure in hippocampal CA3 region.

Objective:To observe the recovery of exercise tolerance among stroke survivors using the cardiopulmonary exercise test (CPET) and analyze the factors influencing it.Methods:A total of 81 stroke survivors hospitalized in the Department of Rehabilitation Medicine of our hospital in year 2018 and 2019 were selected. The general clinical data of all patients were collected retrospectively and combined with the data from CPET to establish a data set. Version 25.0 of the SPSS software was used for multiple linear regressions analysis, with the peak oxygen uptake as the dependent variable, and the age, Brunnstrom stage, peak power, peak heart rate, peak respiratory exchange ratio, peak breathing reserve, peak ventilation per minute, the slope of the VE-VCO 2 curve (ΔVE/ΔVCO 2) and peak end tidal partial pressure of carbon dioxide as independent variables. Results:Stroke survivors at Brunnstrom stage III Ⅲ, Ⅳ and Ⅴ or higher decreased sequentially with their age, but their peak oxygen uptake increased gradually. The multiple linear regression model constructed by " stepwise method" showed that the fitted multiple linear regression equation was statistically significant ( F=100.228, P<0.001). Moreover, the average peak power, peak heart rate, peak ventilation per minute and the slope of the VE-VCO 2 curve were all found to be significant independent predictors of peak oxygen uptake in these stroke survivors. Conclusions:Skeletal muscle power, cardiac function, pulmonary ventilation and ventilation efficiency are useful independent predictors of the exercise tolerance of stroke survivors.