Effects of ganoderma triterpenoids combined with exogenous GM1 on cognitive function and hippocampal synaptic structure in rats with epilepsy / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To study the intervention effect of ganoderma triterpenoids combined with exogenous monosialotetrahexosyl ganglioside(GM1) on cognitive dysfunction and synaptic ultrastructure of hippocampal neurons in rats with epilepsy caused by pentylenetetrazol(PTZ).Methods:A total of 40 Sprague-Dawley rats were divided into blank control group, epileptic model group, ganoderma triterpenoids group, GM1 group and GM1 combined with ganoderma triterpenoids group according to the random number table method( n=8 in each group). The rats were intraperitoneally injected with PTZ subconvulsant dose (35 mg·kg -1·d -1) once a day for 28 days to replicate the models of chronic epilepsy. And the rats in different medication groups were given corresponding administration based on daily intraperitoneal injection of PTZ(GM1 intraperitoneal injection of 30 mg·kg -1·d -1, ganoderma triterpenoids gavage 1 000 mg·kg -1·d -1). Morris water maze was used to test the spatial exploration and learning and memory ability of epileptic rats.Transmission electron microscopy was used to observe the ultrastructure of hippocampal neurons in epileptic rats.Immunofluorescence staining was used to observe expression levels of cofilin and SYN protein in hippocampus CA1 of rats. In addition, Western blot was used to detect the expression levels of cofilin, p-cofilin and synaptophysin(SYN) protein in hippocampus of rats. SPSS 17.0 software was used for statistical analysis. Repeated one-way ANOVA was used for comparing among groups, LSD test was used for pairwise comparisons. Results:Morris water maze results showed that there were statistically significant differences in escape latency, times of crossing the platform and time spent in the target quadrant among the groups( F=5.259, 8.240, 5.961, all P<0.05). Compared with the epilepsy model group, the escape latencies((20.31±7.39) s, (21.81±6.05) s, (17.66±4.76) s) of the ganoderma triterpenoids group, GM1 group and GM1 combined with ganoderma triterpenoids group were shorter (all P<0.05), the numbers of crossing the platform ((4.63±1.41) times, (4.50±1.93) times, (5.50±1.77) times) were more (all P<0.05), the residence time in target quadrant ((31.91±5.00) s, (30.49±5.72) s, (35.70±5.34) s) were longer (all P<0.05). And the most obvious change was found in the GM1 combined with ganoderma triterpenoids group ( P<0.01). The results of transmission electron microscope showed that there were significant differences in the numbers of hippocampal neurons synapses, the synaptic gap, the density of postsynaptic membrane and length of active area of postsynaptic membrane among the groups( F=3.693, 7.201, 5.012, 4.033, all P<0.05). Compared with the epilepsy model group, the numbers of synapses ((8.00±1.79), (7.83±1.84), (8.50±1.87)) in the ganoderma triterpenoids group, GM1 group and GM1 combined with ganoderma triterpenoids group were all more (all P<0.05), synaptic gap ((33.83±3.81)nm, (32.43±4.14)nm, (30.23±3.08)nm)were narrower, and the postsynaptic dense substances ((57.50±6.03)nm, (58.10±2.40)nm, (60.73±3.81)nm) were all thicker (all P<0.05). The length of active region of postsynaptic membrane ((271.66±11.80) nm, (279.06±13.58) nm) in ganoderma triterpenoid group and GM1 combined with ganoderma triterpenoids group were longer than that in epilepsy model group (both P<0.05). Immunofluorescence results showed that the average fluorescence intensity of cofilin in the epilepsy model group was higher than that in the blank control group, and the average fluorescence intensity of SYN was lower than that in the blank control group (both P<0.05). The average fluorescence intensity of cofilin in GM1 group and GM1 combined with ganoderma triterpenoids group were lower than that in epilepsy model group (both P<0.05), and the average fluorescence intensity of SYN in ganoderma lucidum triterpenoids combined with GM1 group was higher than that in epilepsy model group ( P<0.05). Western blot showed that the expression levels of cofilin protein in the epilepsy model group was higher than that in the blank control group ((1.454±0.080), (1.092±0.099), P<0.05), and the expression of p-cofilin and SYN were lower than those in the blank control group ((1.103±0.120) vs (1.420±0.934), (1.650±0.062) vs (1.958±0.062), both P<0.05). The expression of cofilin protein ((1.227±0.071), (1.262±0.078), (1.162±0.129), P<0.05) in ganoderma triterpenoids group, GM1 group and GM1 combined with ganoderma triterpenoids group were lower than that in epilepsy model group, and the expression levels of p-cofilin(1.357±0.199) and SYN protein(1.873±0.010) in ganoderma triterpenoids combined with GM1 group were higher than that in epilepsy model group (both P<0.05). Compared with ganoderma lucidum triterpenoids group and GM1 group, there was no significant difference in each index of GM1 combined with ganoderma triterpenoids group (all P>0.05). Conclusion:GM1 combined with ganoderma triterpenoids may promote the synaptic plasticity of neurons, improve the learning and memory ability of epileptic rats.Combination medication is better than single medication in some observed indicators.