Comparison of ß-Amyloid Plaque Labeling Methods: Antibody Staining, Gallyas Silver Staining, and Thioflavin-S Staining.

Objective To evaluate senile plaque formation and compare the sensitivity of three different ß-amyloid (Aß) labeling methods (antibody staining, Gallyas silver staining, and thioflavin-S staining) to detect Aß deposition.Methods APPswe/PSEN1dE9 transgenic mice (APP/PS1) of different ages were used to examine spatiotemporal changes in Aß plaque deposition. Antibody staining, Gallyas silver staining, and thioflavin-S staining were used to detect Aß plaque deposition in the same brain region of adjacent slices from model mice, and the results were compared.Results With aging, Aß plaques first appeared in the cortex and then the deposition increased throughout the whole brain. Significantly greater plaque deposition was detected by 6E10 antibody than that analyzed with Gallyas silver staining or thioflavin-S staining (P<0.05). Plaque deposition did not show significant difference between the APP/PS1 mice brains assayed with Gallyas silver staining and ones with thioflavin-S staining (P=0.0033).Conclusions The APP/PS1 mouse model of Alzheimer's disease could mimick the progress of Aß plaques occurred in patients with Alzheimer's disease. Antibody detection of Aß deposition may be more sensitive than chemical staining methods.

Expressions of CCAAT/enhancer-binding Protein Homologous Protein and Calnexin in the Hippocampus of a Mouse Model of Mesial Temporal Lobe Epilepsy.

Objective To explore the temporal and spatial distribution of CCAAT/enhancer-binding protein homologous protein (CHOP) and calnexin (CNX) in the dentate gyrus of mesial temporal lobe epilepsy (mTLE) mouse model. Methods We used kainic acid (KA) to induce acute phase (12 h and 24 h) mTLE mouse models and performed Western blotting and immunofluorescence to detect the different expressions and distribution pattern of CHOP and CNX in CA3 of the hippocampus. Results Compared with the controls,the expressions of CHOP(F=1.136,P=0.4069) and CNX (F=2.378,P=0.2087) did not increase in CA3 of hippocampus 12 h following KA injection in the acute phase of mTLE mouse models,whereas the expressions in CA1 and CA3 of hippocampus 24 h after injection were significantly higher (F=8.510,P=0.0362;F=6.968,P=0.0497,respectively). As shown by immunofluorescence analysis,CHOP was expressed mainly in CA3 of hippocampus 12 h after KA injection,and increased in CA1 and CA3 24 h after KA administration. Compared with the controls,the expressions of CHOP(F=24.480,P=0.0057) and CNX (F=7.149,P=0.0478) were significantly higher 24 h after KA injection.Conclusions The expression of CHOP increases along with the progression of seizures,indicating the increased level of endoplasmic reticulum stress. An increasing number of CNX,which serves as molecular chaperone,may be needed to facilitate the unfolded protein to complete the folding process.

Establishment of a chronic restraint stress model of depression with C57BL/6J mice.

OBJECTIVE: To establish a chronic restraint stress (CRS) model of depression,using C57BL/6J mice. METHODS: Totally 20 C57BL/6J mice were screened by weight,sucrose preference,and the results of open-field test. Then,they were equally randomized into two groups:normal control (NC) group and CRS group. Mice in the CRS group were under restraint 4 hours a day and their behavioral changes were evaluated after 21 days. RESULTS: The immobility time was significantly longer in CRS mice [(131.70 ± 21.65) s] compared with controls [(68.88 ± 8.43) s] (P=0.0304). CRS mice showed a significant decrease in sucrose preference during the time 0-24 h [(66.21 ±3.24)% vs.(79.46 ± 3.85)%, P=0.0196] and 0-48 h [(73.25 ± 1.50)% vs.(80.20 ± 2.26)%, P=0.0248] compared with controls. CONCLUSION: The C57BL/6J mice CRS models of depression were successfully established.

[Expression of growth-associated protein 43 in the hippocampus of mesial temporal lobe epilepsy mouse model].

OBJECTIVE: To explore the temporal and spatial distribution of growth-associated protein 43(GAP-43)and phosphorylated growth-associated protein 43(p-GAP-43)in the dentate gyrus of mesial temporal lobe epilepsy(MTLE)mouse model. METHODS: MTLE mouse model was established by using the kainic acid(KA)induction. Immunohistochemistry and Western blotting were applied to detect the expressions of GAP-43 and p-GAP-43 in different stages of epileptogenesis. RESULTS: Both in the epileptic and control mice, high GAP-43 expression level was detected in the dentate gyrus, hilus, and inner molecular layer of hippocampus. Decreased p-GAP-43 expression was detected 5 days, 2 weeks, and 5 weeks after KA-induced seizures. CONCLUSION: The decreased p-GAP-43 expression in the duration of seizure may play an important role in the synaptic reorganization of the sclerotic hippocampus.

Spatio-temporal expression study of phosphorylated 70-kDa ribosomal S6 kinase (p70S6k) in mesial temporal lobe epilepsy.

OBJECTIVE: To determine the spatio-temporal expression of p70S6k activation in hippocampus in mesial temporal lobe epilepsy. METHODS: Temporal lobe epilepsy model was established by stereotaxically unilateral and intrahippocampal injection of kainite acid (KA) in adult male C57BL/6 mice. Latent and chronic epileptogenesis were represented by mice 5 days after KA injection (n = 5) and mice 5 weeks after KA injection (n = 8), respectively. Control mice (n = 5) were injected with saline. Immunohistochemical assays were performed on brain sections of the mice. RESULTS: Hippocampus both ipsilateral and contralateral to the KA injection displayed significantly up-regulated pS6 immunoreactivity in dispersed granule cells in 5-day and 5-week model mice. CONCLUSION: The activation of p70S6k is mainly located in the dentate gyrus in KA-induced mouse model of temporal lobe epilepsy, indicating that the activation may be related with the disperse degree and hypertrophy of granule cells.

[Role of beta-catenin in the pathogenesis of mesial temporal lobe epilepsy].

OBJECTIVE: To explore the role of beta-catenin in the pathogenesis of mesial temporal lobe epilepsy. METHODS: Kainic acid-induced rat models of medial temporal lobe epilepsy was established. The expression of beta-catenin in the normal mice and the model mice were detected using Western blot analysis. The expression of beta-catenin at human hippocampus was detected using immunohistochemical analysis and immunofluorescence and compared between patients with non-hippocampal sclerosis temporal lobe epilepsy and those with hippocampal sclerosis epilepsy. RESULTS: The pathologies of model mice were similar with those in mice with hippocampal sclerosis temporal lobe epilepsy, demonstrating that the mice model was successfully established. Western blot analysis showed no significant difference of beta-catenin expression between normal mice and model mice. As shown by immunohistochemical analysis and immunofluorescence, beta-catenin expression in human hippocampus was also not significantly different between patients with temporal lobe epilepsy without hippocampal sclerosis and those with hippocampal sclerosis. CONCLUSION: Beta-catenin may not be involved in the development of hippocampal sclerosis of mesial temporal lobe epilepsy.

Mapping the spatio-temporal pattern of the mammalian target of rapamycin (mTOR) activation in temporal lobe epilepsy.

Growing evidence from rodent models of temporal lobe epilepsy (TLE) indicates that dysregulation of the mammalian target of rapamycin (mTOR) pathway is involved in seizures and epileptogenesis. However, the role of the mTOR pathway in the epileptogenic process remains poorly understood. Here, we used an animal model of TLE and sclerotic hippocampus from patients with refractory TLE to determine whether cell-type specific activation of mTOR signaling occurs during each stage of epileptogenesis. In the TLE mouse model, we found that hyperactivation of the mTOR pathway is present in distinct hippocampal subfields at three different stages after kainate-induced seizures, and occurs in neurons of the granular and pyramidal cell layers, in reactive astrocytes, and in dispersed granule cells, respectively. In agreement with the findings in TLE mice, upregulated mTOR was observed in the sclerotic hippocampus of TLE patients. All sclerotic hippocampus (n = 13) exhibited widespread reactive astrocytes with overactivated mTOR, some of which invaded the dispersed granular layer. Moreover, two sclerotic hippocampus exhibited mTOR activation in some of the granule cells, which was accompanied by cell body hypertrophy. Taken together, our results indicate that mTOR activation is most prominent in reactive astrocytes in both an animal model of TLE and the sclerotic hippocampus from patients with drug resistant TLE.