Effects of ICG-001 on autistic behaviors and the development of hippocampal dendritic spine morphology in rats / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the effects of the compound ICG-001 on autism-like behaviors and the morphological development of dendritic spines in hippocampal pyramidal neurons of rats.Methods:Healthy Wistar rats were mated.The offspring were divided into the saline-treated group, ICG-001 control group, Sodium valproate (VPA) group and ICG-001 treatment group by using the random number table method.Each group had 12 rats.Social interaction, repetitive, compulsive and anxiety-like behaviors in rodents were assessed by three-chambered social approach, marble burying, open-field and elevated plus maze tests.The number of neuronal nuclei (NeuN)-positive neurons in the hippocampal CA1 region was calculated by the immunofluorescence method.Golgi staining was carried out to detect the density and morphological changes of dendritic spines in hippocampal pyramidal neurons of rats.The expression of phosphorylated LIM kinase 1(LIMK1), phosphorylated actin binding protein(Cofilin), fibros actin (F-actin) and developmentally-regulated brain protein A (Drebrin A) was examined by Western blot.The univariate analysis was made to examine whether the difference was statistically significant, and the data between groups were compared by the Tukey method. Results:(1) In the three-chambered social approach test, the rats in the saline-treated group, ICG-001 control group, VPA group and ICG-001 treatment group spent (219.42±5.38) s, (218.67±10.12) s, (126.58±5.02) s, and (218.58±6.63) s in the chamber, respectively.The corresponding preference score of the said 4 groups were 0.43±0.05, 0.43±0.04, 0.22±0.01 and 0.42±0.04, respectively.Compared with the VPA group, the ICG-001 treatment group spent longer time in the chamber and had a higher preference score (all P<0.05). (2) In the marble burying experiment, the number of marbles buried in said 4 groups were 9.13±0.52, 9.08±0.64, 15.13±0.82 and 9.42±0.86, respectively.ICG-001-treated rats buried markedly less marbles than VPA-exposed rats ( P<0.05). (3) In the open-field test, the rats in the said 4 groups spent (82.33±1.83) s, (81.32±4.19) s, (45.51±3.02) s and (81.44±3.19) s in the center area, respectively.Administration of ICG-001 significantly increased the time that VPA-exposed rats spent in the center area ( P<0.05). (4)In the elevated plus maze trial, the rats in the said 4 groups spent (107.75±7.23) s, (106.08±7.50) s, (63.42±1.91) s and (106.67±7.07) s in open arms, respectively.ICG-001 treatment notably increased the time that VPA-exposed rats spent in open arms ( P<0.05). (5) Immunofluorescence analysis results revealed that the number of NeuN-positive cells in the hippocampal CA1 region of said 4 groups was (41.83±1.17)×10 4/μm 2, (41.00±0.77)×10 4/μm 2, (27.17±0.95)×10 4/μm 2 and (40.00±0.90)×10 4/μm 2, respectively.ICG-001 treatment normalized the alteration in the number of NeuN-containing neurons in VPA-exposed rats ( P<0.05). (6) Golgi staining showed that the density of dendritic spines in hippocampal CA1 pyramidal neurons of said 4 groups was (0.74±0.04)/μm, (0.73±0.03)/μm, (0.49±0.03)/μm and (0.70±0.02) /μm, respectively.Of all types of dendritic spines, mushroom spines accounted for (0.49±0.02)%, (0.49±0.02)%, (0.33±0.02)% and (0.43±0.02) % in said 4 groups.Thin spines accounted for (0.27±0.02)%, (0.26±0.02)%, (0.34±0.01)% and (0.26±0.01) % in said 4 groups, respectively.Compared with the VPA group, the ICG-001 treatment group showed a significant increase in the density of dendritic spines in hippocampal CA1 pyramidal neurons ( P<0.05). After ICG-001 treatment, the number of mushroom spines greatly increased and the number of thin spines sharply decreased in VPA-exposed rats (all P<0.05). (7) According to Western blot test results, the phosphorylated LIMK1/LIMK1 ratio of the hippocampus in said 4 groups were 100.33±2.30, 99.34±2.28, 57.76±4.10 and 99.13±1.90, respectively.The phosphorylated Cofilin /Cofilin ratio were 100.18±2.43, 100.18±1.70, 57.12±1.88 and 99.53±1.69, respectively.The F-actin/globular actin(G-actin) ratio were 100.07±0.86, 99.99±1.72, 51.19±1.23 and 99.28±3.17, respectively.The expression level of Drebrin A were 100.79±1.19, 100.12±2.04, 52.86±3.26 and 99.97±2.44, respectively.Administration of ICG-001 effectively prevented the decrease of phosphorylated LIMK1, phosphorylated Cofilin, F-actin and Drebrin A in the hippocampus of VPA-exposed rats (all P<0.05). Conclusions:ICG-001 regulates the LIMK1/Cofilin signaling pathway, promotes the generation of F-actin, increases the expression of Drebrin A, and thereby alleviates autistic-associated symptoms.