Influence of alginic sodium diester on intraneuronal Ca2+ content and nerve cell apoptosis before and after reperfusion in experimental ischemic rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Alginic sodium diester (ASD) possesses neuroprotective function because of its selective calcium antagonist effects.OBJECTIVE: To compare the influences of ASD on intraneuronal Ca2+content and nerve cell apoptosis before and after reperfusion in focal cerebral ischemic rats.DESIGN: Randomized controlled observation.SETTING: Neurological Department of Xiangya Hospital Affiliated to South China University; Laser Orthopedic Surgery of the First Hospital Affiliated to Southern China University.MATERIALS: This experiment was carried out between November 2003and April 2004 at the Neurological Department of Xiangya Hospital Affiliated to South China University. A total of 65 male SD rats were recruited and randomized into 6 groups; 17 got lost during the experiment, and the other 48 rats completed the experiment with 8 rats in each group.METHODS: In sham operation group, an incision was made on rats' cervical skin and sutured. Right cerebral middle artery was occluded in rats of ischemic group, ASD 5 mg/kg preischemic group, ASD 5 mg/kg postischemic group, ASD 10 mg/kg preischemic group, and ASD 10 mg/kg postischemic group. After that, rats in all but ischemic group were subjected to intraperitoneal injection of various dosage of ASD or excipient 30minutes before reperfusion and 5 hours after reperfusion. FCM was used to determine intraneuronal Ca2+ content and rate of nerve cell apoptosis;meanwhile, neurological dysfunction was scored.MAIN OUTCOME MEASURES: [1] Influence of ASD on the score for neurological dysfunction, intraneuronal Ca2+ fluorescence intensity, and neuronal apoptosis in rats with right cerebral middle artery ischemia. [2]Correlation of behavioral obstacle score with intraneuronal Ca2+ fluorescence intensity and neuronal apoptosis in rats with right cerebral middle artery ischemia.RESULTS: Totally 65 rats were enrolled in this study, 17 of which got lost and the other 48 rats entered the result analysis. [1] Influence of ASD on the score for neurological dysfunction, intraneuronal Ca2+ fluorescence intensity, and neuronal apoptosis in rats with right cerebral middle artery ischemia: The score was obviously reduced in ASD 5 mg/kg preischemic group, ASD 5 mg/kg postischemic group, ASD 10 mg/kg preischemic group and ASD 10 mg/kg postischemic group as compared with ischemic group (1.80±0.21, 2.20±0.23, 1.20±0.11, 2.00±0.22, 3.40±0.65); moreover,functional improvement was more obvious due to pre-reperfusional administration than post-reperfusional administration. Intraneuronal Ca2+ concentration was reduced after ASD administration at different degrees and lower than that of ischemic group. Decrement of intraneuronal Ca2+ concentration was found most obvious due to 10 mg/kg ASD administration 30 minutes before reperfusion, approximately reduced by 70%; moreover, neuronal apoptosis rate on the ischemic side was obviously suppressed by ASD administration, displaying time-dependent manner, with apoptotic suppression effect more obvious in pre-reperfusional group than in post-reperfusional group (5.68%, 10.03%; 4.00%, 9.91%). [2] Correlation of behavioral obstacle score of right cerebral middle artery ischemic rats with intraneuronal Ca2+ fluorescence intensity and membrane associated protein/propidium iodide apoptosis: Obvious positive correlation was found between behavioral obstacle score and intraneuronal Ca2+ fluorescence intensity and detection rate of membrane associated protein/propidium iodide apoptosis (r=0.51,0.62, P ＜ 0.05); intraneuronal Ca2+ fluorescence intensity was also positively correlated with the detection rate of membrane associated protein/propidium iodide apoptosis (r=0.84, P ＜ 0.05).CONCLUSION: [1] ASD can exert anti-apoptosis effect by suppressing the increment of intraneuronal Ca2+ concentration, thus having neuroprotective function and ultimately improving neurological dysfunction. [2] Its effect displays time-dependent manner, and neurological functional improvement is more obvious by pre-reperfusional administration than by post-operational administration.