| Objective: Epilepsy is a common neurological disorder.It is a brain dysfunction due to the neurons suddenly abnormality and excessive synchronous discharge.Recurrent epilepsy can cause cognitive disorder.So far,the mechanism of the cognitive handicap after epilepsy is not clear,probably caused by following aspects: apoptosis,oxidative stress and ion channels and other pathologic physiology mechanism.Studies had shown that apoptosis pathway was believed to be an important pathological process through which epilepsy could cause brain damage.Astaxanthin is a kind of the carotinoid.It exists in shrimp,crabs,algae and other marine organisms.It has biological activities such as anti-oxidant,anti-inflammatory and anti-apoptotic.It plays positive role in the prevention and treatment of neurological disease,skin disease and cardiovascular disease.The pharmacological value of ATX has attracted considerable attention of scholars.In this experiment,we had chosen male SD rats as experimental animals.We established the epileptic model by chronic amygadala electrical kindling.With the interruption of ATX,the experiment was divided into control group,epilepsy group,ATX low dose electrical stimulation group and ATX high dose electrical stimulation group.We investigated the change of rats' learning ability in different groups by the Morris water maze.Western Blot method was used to detect the expression changes of bcl-2 and bax inhibition of apoptosis in the hippocampus tissues.It aimed to determine the neuroprotective effects of ATX and to explore the possible mechanism of ATX.Methods: Sixty 7-8 week male adult healthy SD rats were divided randomly into control group,chronic electrical kindling epilepsy group,ATX low dose electrical stimulation group and ATX high dose electrical stimulation group.Every each had fifteen rats.Control group(C group)had fifteen rats that were only electrode-implanted but not electrically-stimulated.Chronic electrical kindling epilepsy group(EP group)had fifteen rats and established epileptic model by amygadala electrical kindling,giving 120% seizure threshold stimulation once a day,a total of 15 days.ATX low dose electrical stimulation group(LD group)had fifteen rats and after the electrodes implanted in their amygdala,they were given 120% seizure threshold stimulation once a day with a total of 15 days.The rats were injected intraperitoneally in a dose of 15mg/kg ATX one hour before the stimulation.ATX high dose electrical stimulation group(HD group)had fifteen rats and after electrodes implanted in their amygdala,they were given 120% seizure threshold stimulation once a day with a total of 15 days.The rats were injected intraperitoneally in a dose of 30mg/kg ATX one hour before the stimulation.24 h after the last ATX injection,Morris water maze test was performed.The experiment includede:(1)Place navigation test: The Morris water maze was prepared as required.The rats were allowed to swim freely in the pool for 120 s to adapt to the environment of the pool.The experiment was conducted on the next day,lasting 5 days.In each trail,the rats were placed into the pool gently at the middle of the circular edge in a randomly selected quadrant,with the nose pointing towards the wall every day at 9 am.If rats could not find escape to the platform within 120 s by themselves,their escape latency was accepted as 120 s.(2)Spatial probe test: On the sixth day,a probe trial was assessed without the platform and the crossing times were recorded.After the test,six rats from each group were perfused and the brains were removed,using Western Blot method to detect the expression changes of bcl-2,bax in the hippocampus tissues.Results:1 Results of Morris water maze: Place navigation test: we summarized the statistical average of the rat escape latency and through comparision between different groups we found that:(1)The first day,the rat escape latency in EP group was longer than C group(P<0.05).The escape latency in HD group and LD group were shorter than EP group(P<0.05),but there was no significant difference between them(P>0.05).The rat escape latency in LD group was longer than HD group(P<0.05),but there was no significant difference between them(P>0.05).(2)The second day: Comparing with the first day,the rat mean escape latency in each group were much shorter(P<0.05).The results of mean escape latency comparison between each group were the same as the first day.(3)The third day: Comparing with the second day,the rat mean escape latency in each group were much shorter(P<0.05).The results of mean escape latency comparison between each group were the same as the second day.(4)The fourth day: Comparing with the third day,the rat mean escape latency in each group were much shorter(P<0.05).The results of mean escape latency comparison between each group were the same as the third day.(5)The fifth day: Comparing with the fourth day,the rat mean escape latency in each group were much shorter(P<0.05).The results of mean escape latency comparison between each group were the same as the fourth day.Spatial probe test: Comparing with C group,the number of crossing times in EP group through the platform quadrant decreased obviously(P<0.05).Comparing with EP group,the number of crossing times in HD group and LD group through the platform quadrant increased obviously(P<0.05).There was no significant difference between them(P>0.05).Comparing with HD group,the number of crossing times in LD group through the platform quadrant decreased(P<0.05),but there was no significant difference between them(P>0.05).2 Result of Western blot: The expression of bcl-2 was significantly decreased in EP group rather than that in C group(P<0.05).The expression of bcl-2 was increased significantly in HD group and LD group compared to the EP group(P<0.05).There was no significant difference between C group,HD group and LD group(P>0.05).The expression of bcl-2 was decreased in LD group rather than that in HD group(P<0.05),but there was no significant difference between them(P>0.05).The expression of bax was significantly increased in EP group compared to the C group(P<0.05).The expression of bax was significantly increased in HD group and LD group compared to the EP group(P<0.05).There was no significant difference between C group,HD group and LD group(P>0.05).The expression of bax was increased in LD group compared to the HD group(P<0.05),but there was no significant difference between them(P>0.05).Conclusions:1 The epileptic model by chronic electrical kindling was established successfully.Epileptic seizures could cause cognitive disorder.2 Epilepsy could decrease the expression of bcl-2 and increase the expression of bax in the hippocampi of rats.Apoptosis pathway is believed to be an important pathological process through which epilepsy can cause brain damage.3 ATX could improve the ability of learning and memory of the epileptic rats.Furthermore,ATX resulted in a significant decrease in the expression of bax and obviously increase in the the expression of bcl-2.These findings suggest that ATX can exert protective effects on cognitive deficits in epileptic rats and its neuroprotection is partly due to the inhibition of apoptosis pathway. |
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