| Objective: To research the changes of synaptogenesis and neural immune function in the prefrontal cortex(PFC) and hippocampus(HC) of autism rats. Make a further study on the roles of synaptogenesis and neural immune in pathogenesis of autism. Method: This autistic animal model wasobtained in the offspring of female Wistar rats that received a single intraperitoneal injection of VPA on the 12.5th pregnancy day. By comparing the normal group rats and the rats in autism model group to observe the growth and development(eye opening time, oblique board test, swimming test)and behavior(the self-grooming test were used to investigate the stereotypy behavior analysis. Three-chambered social test were used to investigate the social behavior and the preference for new things).Nissl stain was used to observed the changes of neurons’ number in PFCⅡ/Ⅲ layer and HC CA3 of control group rats and model group rats in P42. Western blot were used to investigate the levels ofneuron、autophagy related protein(LC3-II、Beclin-1、P62)、synapse associated protein(Syn 、 PSD-95 、 Gephyrin) 、 microglia(Iba1) and astrocytes(GFAP)、inflammatory cytokines(IL-6、IL-1β) in the PFC and HC of control group rats and model group rats in P42. Immunohistochemistry were used to investigated the changes of microglia and astrocytes in the number and morphological in PFC and DG of control group rats and model group rats in P42. Result: 1. The state of the development:the autistic ones advanced timing of eye opening, P13, P14 and P15 had significant difference(P<0.05),P12 and P16 had no significant difference(P>0.05);Oblique board test P7, P8, P9 of autistic rats significantly prolong the time of turning than the normal group(P<0.05),there is no difference between the two groups in P10(P<0.05).Swimming performance On the P9、P11、P13、P15,compared with the normal rats, the swimming ability of autism model rats was significantly lower, the difference was statistically significant.2. Behavior detection Self-grooming test: the cumulative self-grooming time was significantly increased(P < 0.05); Threechambered social test: at the first 10 min, rats in the control group stay in the first strange case significantly longer than staying in the empty box, while the residence time of autistic rats had no significant difference in the first box with strange1 rats and empty box(P>0.05);in the later 10 min, control rats stay in the box with stranger2 significantly longer than in the first box with stranger1(P<0.05), while the residence time of autistic rats had no significant difference in the first box with strange1 rats and in the box with stranger2(P>0.05). 3.The results of Nissl stain showed that the number of neurons in the PFCⅡ/Ⅲ layer and HC CA3 was more than that in the normal group(P< 0.05).4. The results of Western blot show that LC3-II、Beclin-1、Gephyrin was significantly decreased(all P<0.05) and TUBB3、P62、Syn、PSD-95、Iba1、GFAP、IL-6、IL-1β was significantly increased(all P<0.05) in PFC and HC of autistic rats of P42 compared with control group. Immunohistochemistry show: Compared with control group, the cell bodies of the Iba1-positive cells in autism model of in P42 became enlarged, neurites retracted and reduced; the process of the GFAP-positive cells in autism model in P42 became enlarged, with neuritis increasing. The results of positive cell counting show that the number of the Iba1-positive cells and GFAP-positive cells in PFC and HC of autistic rats was significantly increased compared with control group(all P < 0.05).Conclusion : The autophagy was inhibition in autism model rats of P42; the synaptic development disorder——excitatory synapses increased and inhibitory synapses decreased, excitatory / inhibitory synaptic imbalance in autism model rats of P42; the neuroimmune disorder in autism model rats of P42——the activation of microglia and astrocyte; inflammatory cytokines increased. |
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