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OBJECTIVE To compare the difference and similaritiy in growth, neurodevelopment and neurobehavioral characteristics between SD rat and C57 mouse models of valproic acid (VPA)induced autism spectrum disorder (ASD), and select an appropriate experimental species for the study of ASD. METHODS SD rats or C57 mice were ip given VPA 600 mg·kg-1 on embryonic day 12.5 of gestation (VPA groups) or an equal dosage of saline (normal control group). The farrowing rate of pregnant rats or mice and 4-day survival rate were observed. The male pups' malformation rate, body mass, tail length, incisor eruption, eye opening and development of fur were detected to observe physiological development. The neurodevelopment was measured in male pups including the number of days taken by surfacing righting reflex, cliff avoidance reflex, air righting reflex, pivoting, crawling and bar holding test and auditory startle to become positive. In addition, three chamber sociability test, open-field test and self-grooming test were used to assess autistic-like behaviors. RESULTS Compared with C57 mice in normal control group, the VPA groups presented a low farrowing rate in pregnant mice (P<0.05), and high external abnormality in new born offspring (P<0.01). However, there was no significant difference between SD rats in normal control group and those in VPA group. Compared with C57 mice in normal control group, the 4-day survival rate of offspring of the VPA group was significantly reduced (P<0.05), but there was no significant difference between SD rats in normal control group and those in VPA group. The male offspring of C57 mice in VPA group showed significant growth retardation compared with the normal control group, such as lower body mass at 20 and 25 d after birth (P<0.05), delayed incisor eruption (P<0.05) and eye opening (P<0.01). Although the body mass of the male offspring SD rats in VPA group was also significantly lower than that of normal control group at the same time points (P<0.01), there was no significant delay in the incisor eruption or eye opening. Compared with the male offspring of SD rats in normal control group, the VPA group had a significant delay in surface righting reflex (PO.01), cliff avoidance reflex (P<0.01), air righting reflex (P<0.05), crawling (P< 0.01) and bar holding test (P<0.01). Compared with the normal control group, pivoting (P<0.05) and bar holding test (P<0.05) in the C57 mice VPA group were delayed. In the three chamber sociability test, open field test and self-grooming test, the male offspring of SD rats in VPA group showed decreased spatial exploration ability (P<0.01), impaired social preference and novelty preference (P<0.01), and repetitive and stereotyped behaviors (P<0.05). VPA mice only exhibited reductions in spatial exploration ability and novelty preference (P<0.05). CONCLUSION If SD rats and C57 mice are exposed to VPA in the second trimester of pregnancy, their male offspring exhibits behavioral abnormalities relevant to ASD. However, SD rats are superior to C57 mice in building ASD animal models in terms of maternal pregnancy condition, cost and model face validity.
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Objective To investigate whether vascular endothelial cells in choroidal neovascularization whether hypoxia condition can up-regulate SNAI1 and activate matrix metalloproteinase (MMP)2 and MMP9 therefore to participate in choroidal neovascularization(CNV).Methods Sixteen SPF male C57 mice aged 6-8 weeks were divided into control group and model group.CNV models were induced by retinal laser photocoagulation,and flatmount and frozen sections of retinal pigment epithelium (RPE)-choroid-sclera compound were prepared at 7 days after modeling.The CNV in flat-mount was examined by Isolectin B4 staining,and the location of SNAI1,MMP2 and MMP9 in frozen sections was determined by immunofluorescence technology.The expression of SNAI1,MMP2 and MMP9 at mRNA level in CNV was detected by real-time fluorescence quantitative PCR (real-time PCR).The use and care of experimental animals complied with Statement for the Use of Animals in Ophthalmic and Visual Research.The RF/6A cells were divided into normoxia group and hypoxia group and cultured for 24 hours in 5％ CO2condition and mix condition of 94％ N2,5％ CO2 and 1％ O2,respectively.The expression of SNAI1,MMP2 and MMP9 in the cells at mRNA and protein levels was detected by real-time PCR and Western blot assay,respectively.Small interfering RNA of SNAI1 (siSNAI1) was transfected into the cells,and then the expression of MMP2 in the cells at mRNA and protein levels was detected by real-time PCR and Western blot assay,respectively,and the migrating number of the cells was assayed by Transwell chamber assay.Results CD31 and SNAI1 positive-response cells were seen in RPE-choroid-sclera flat-mounts under the laser scanning confocal microscope.The relative expression levels of SNAI1mRNA and MMP2 mRNA in RPE-choroid-sclera tissues were higher in the model group than those in the control group (SNAI1 mRNA:1.291 ±0.060 vs.0.759±0.074,P =0.001;MMP2 mRNA:1.610±0.424 vs.0.772 ±0.080,P =0.044).The expression of MMP9 mRNA was not significantly elevated between model group and control group (P＞0.05).The relative expression level of MMP2 mRNA was higher in comparison with MMP9 mRNA in the model group (P＜0.01).The relative expressions of hypoxic induced factor 1α (HIF-1α),SNAI1 and MMP2 at mRNA level and protein level in RF/6A cells were significantly higher in the hypoxia group than those in the normoxia group (all at P＜0.05) and no considerable difference was seen in MMP9 mRNA expression between the two groups (P＞0.05).The relative expressions of MMP2 mRNA in the cells were 0.217±0.036 and 0.818±0.105,and those of MMP2 protein in the cells were 0.236±0.009 and 1.043±0.120 in the hypoxia+siSNAI1 group and only hypoxia group,respectively,with significant differences between them (P =0.002,0.003).The migrating number of the cells was (254.60 ±71.31)/field in the hypoxia+siSNAI1 group,which was significantly less than (534.10±96.21) /field in the control group (P =0.029).Conclusions The hypoxic environment at CNV can activate MMP2 by up-regulating the expression of SNAI1,which promotes the migration of vascular endothelial cells and therefore participates in CNV formation,and the intervention of SNAI1 activation under the hypoxic condition can inhibit this process.
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Objective To investigate the effects of ceftriaxone on depressive-like behavior and changes of hippocampal glutamate transporter-1 (GLT-1) in C57 mice depression model,and to further explore the molecular mechanism of ceftriaxone on antidepressant action.Methods Thirty male C57 mice were randomly divided into control group(group A,n=10),CUS group(group B,n=10) and CUS+ceftriaxone group(group C,n=10).The mice of the CUS group and the CUS+ceftriaxone group were subjected to chronic unpredictable stress (CUS) for 2 sessions per day for 21 days.Then,the mice of the CUS+ceftriaxone group were given ceftriaxone for 21 days.Behavioral changes were assessed by the sucrose preference test and open field test.The GLT-1 protein levels in the hippocampus were detected by Western blot analysis at the end of the ceftriaxone treatment.Results (1) Compared with the control group,the percentage of sucrose preference,the total traveled distance,the moved velocity,and the frequencies of rearing of the CUS group were significantly decreased(P＜0.05) at the 21 days.However,the percentage of sucrose preference ((78.74 ± 3.54) ％),the total traveled distance ((6818.35 ± 505.14) cm),the moved velocity((12.36±0.89) cm/s),and the frequencies of rearing(58.20±4.05) of the CUS+ceftriaxone group at the end of the ceftriaxone treatment were improved significantly compared with the CUS group ((59.46 ± 2.75) ％,(2931.71±271.89) cm,(5.84±0.42) cm/s,(26.20±2.62),P＜0.05).(2) Western blot analysis indicated significant reductions of the GLT-1 protein levels in the hippocampus of CUS group (versus the control mice:P ＜0.05),and chronic ceftriaxone treatment reversed the CUS-induced decrease in the GLT-1 levels(P＜0.05).Conclusion Ceftriaxone might significantly improve depressive-like behavior in C57 mice depression model.Chronic unpredictable stress (CUS) could down-regulate the GLT-1 protein levels in the hippocampus,which are reversed by ceftriaxone.These results further support the notion enhanced expression of the GLT-1 protcin can be molecular mechanism of ceftriaxone on antidepressant action.
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Objective To investigate the feasibility and effectiveness of C57 mice depression model established by chronic unpredictable mild stress (CUMS) and separation.Methods 30 male C57 mice were randomly divided into three groups:CUMS + separation group (group CS),CUMS + separation + fluoxetine group (group CSF),and control group (group C).The mice of group CS and group CSF were fed with chronic unpredictable mild stress (CUMS) and separation for 3 weeks.Then,the mice of group CSF were given fluoxetine.To record the food intake/body weight,liquid consumption and field test of the mice at relevant time point.Results Compared with control group,the food intake/body weight,total route in the field test,and the sucrose solution consumption in liquid consumption test of group CS and group CSF decreased significantly (P＜0.05) at the 21th days.But after giving fluoxetine for 14 days,group CSF had no significant differences with group C except sucrose solution consumption.Although the difference of sucrose solution preferences was significant compared with control group(P＜0.05),it was improved significantly compared with CS group (P＜ 0.05).Conclusion The C57 mice depression model established by CUMS and separation are feasible and effective,and it is the ideal animal model of depression.
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Hepatic fibrsosis was induced by carbon tetrachloride in mice C 57.Then the feed containing Dangshen pollen was given to the animals. It was demonstrated under the electron microscope that the Dangshen pollen lowered the activity of the fibroblasts around the central vein and the fatstoring ceils of sinusoids, and lowered the grade of collagenous fibers of Disse's spaces (P