The phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) signaling pathway is considered important for cellsurvival and has been shown to mediate various anti-apoptotic biological effects. This study explored the role of the Tol -like receptor 4 (TLR4)-mediated PI3K/AKT-glycogen syn-thase kinase 3β (GSK-3β) signaling pathways in lipopolysaccharide-induced apoptosis in a primary culture of hippocampal neurons. Results demonstrated that the apoptotic ratio of hippocampal neurons stimulated by lipopolysaccharide was significantly higher compared with the control group. Both the expression of P-AKTSer473 and P-GSK-3βSer9 in hippocampal neurons stimulated by lipopo-polysaccharide decreased compared with the control, while the level of active Caspase-3 and the ratio of Bax/Bcl-2 were significantly increased. The level of active Caspase-3 and the ratio of Bax/Bcl-2 in hippocampal neurons treated with TLR4 antibody or the GSK-3β inhibitor, LiCl, creased before intervention with lipopolysaccharide, but increased after treatment with the AKT hibitor, LY294002. These findings suggest that the TLR4-PI3K/AKT-GSK3β signaling pathway may be involved in lipopolysaccharide-induced apoptosis of hippocampal neurons.
作者： 刊期： 2013年第29期
Caveolin-1 is involved in the regulation of synaptic plasticity, but the relationship between its pression and cognitive function during aging remains controversial. To explore the relationship be-tween synaptic plasticity in the aging process and changes in learning and memory, we examined caveolin-1 expression in the hippocampus, cortex and cerebel um of rats at different ages. We also examined the relationship between the expression of caveolin-1 and synaptophysin, a marker of synaptic plasticity. Hippocampal caveolin-1 and synaptophysin expression in aged (22-24 month old) rats was significantly lower than that in young (1 month old) and adult (4 months old) rats. pression levels of both proteins were significantly greater in the cortex of aged rats than in that of young or adult rats, and levels were similar between the three age groups in the cerebel um. Linear regression analysis revealed that hippocampal expression of synaptophysin was associated with memory and learning abilities. Moreover, synaptophysin expression correlated positively with caveolin-1 expression in the hippocampus, cortex and cerebel um. These results confirm that caveolin-1 has a regulatory effect on synaptic plasticity, and suggest that the downregulation of hippocampal caveolin-1 expression causes a decrease in synaptic plasticity during physiological aging.
作者： 刊期： 2013年第29期
Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed a diet containing different doses of zinc (50, 100, 200 mg/kg) for 9 weeks, and oral y administered aluminum chloride (300 mg/kg daily) from the third week for 7 consecutive weeks. Open-field behavioral test results showed that the number of rearings in the group given the 100 mg/kg zinc supplement was significantly increased compared with the group given the 50 mg/kg zinc supplement. Malondialdehyde content in the cerebrum was significantly decreased, while dopamine and 5-hydroxytryptamine levels were increased in the groups given the diet plemented with 100 and 200 mg/kg zinc, compared with the group given the diet supplemented with 50 mg/kg zinc. The acetylcholinesterase activity in the cerebrum was significantly decreased in the group given the 100 mg/kg zinc supplement. Hematoxylin-eosin staining revealed evident patho-logical damage in the hippocampus of rats in the group given the diet supplemented with 50 mg/kg zinc, but the damage was attenuated in the groups given the diet supplemented with 100 and 200 mg/kg zinc. Our findings suggest that zinc is a potential neuroprotective agent against alumi-num-induced neurotoxicity in rats, and the optimal dosages are 100 and 200 mg/kg.
作者： 刊期： 2013年第29期
NR2B subunits are involved in regulating aging, in particular, age-related learning and memory deficits. We examined 19-month-old NR2B transgenic mice and their littermate controls. First, we detected expression of the NR2B subunit gene, Grin2b, in the neocortex of transgenic mice using real-time PCR. Next, we used microarrays to examine differences in neocortical gene expression. Pathway and signal-net analyses identified multiple pathways altered in the transgenic mice, in-cluding the P53, Jak-STAT, Wnt, and Notch pathways, as wel as regulation of the actin cytoskeleton and neuroactive ligand-receptor interactions. Further signal-net analysis highlighted the P53 and insulin-like growth factor pathways as key regulatory pathways. Our results provide new insight into understanding the molecular mechanisms of NR2B regulated age-related memory storage, normal organismal aging and age-related disease.
作者： 刊期： 2013年第29期
One of the wel -defined sexual y dimorphic structures in the brain is the sexual y dimorphic nucleus, a cluster of cells located in the preoptic area of the hypothalamus. The rodent sexual y dimorphic nucleus of the preoptic area can be delineated histological y using conventional Nissl staining or immunohistochemical y using calbindin D28K immunoreactivity. There is increasing use of the bindin D28K-delineated neural cluster to define the sexual y dimorphic nucleus of the preoptic area in rodents. Several mechanisms are proposed to underlie the processes that contribute to the sexual dimorphism (size difference) of the sexual y dimorphic nucleus of the preoptic area. Recent evidence indicates that stem cellactivity, including proliferation and migration presumably from the 3rd ventricle stem cellniche, may play a critical role in the postnatal development of the sexual y dimorphic nucleus of the preoptic area and its distinguishing sexual y dimorphic feature: a signifi-cantly larger volume in males. Sex hormones and estrogen-like compounds can affect the size of the sexual y dimorphic nucleus of the preoptic area. Despite considerable research, it remains un-clear whether estrogen-like compounds and/or sex hormones increase size of the sexual y dimor-phic nucleus of the preoptic area via an increase in stem cellactivity originating from the 3rd ventricle stem cellniche.
作者： 刊期： 2013年第29期
The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney’s free fal ing method. The brains were harvested at 2, 6 and 24 hours, and at 3 and 5 days after injury. Changes in brain water content were determined using the wet and dry weights. Our results showed that water content of tissue significantly increased after traumatic brain injury, and reached minimum at 24 hours. Hematoxylin-eosin staining revealed pathological impairment of brain tissue at each time point after injury, particularly at 3 days, with nerve celledema, degenera-tion, and necrosis observed, and the apoptotic rate significantly increased. Immunohistochemistry and western blot analysis revealed that the expression of occludin at the injured site gradual y de-creased as injury time advanced and reached a minimum at 3 days after injury; the expression of connexin 43 gradual y increased as injury time advanced and reached a peak at 24 hours after in-jury. The experimental findings indicate that changes in occludin and connexin 43 expression were consistent with the development of brain edema, and may reflect the pathogenesis of brain injury.
作者： 刊期： 2013年第29期
Synaptosomal-associated protein-25 is an important factor for synaptic functions and cognition. In this study, subarachnoid hemorrhage models with spatial learning disorder were established through a blood injection into the chiasmatic cistern. Immunohistochemical staining and western blot analysis results showed that synaptosomal-associated protein-25 expression in the temporal lobe, hippocampus, and cerebel um significantly lower at days 1 and 3 fol owing subarachnoid morrhage. Our findings indicate that synaptosomal-associated protein-25 expression was down-regulated in the rat brain after subarachnoid hemorrhage.
作者： 刊期： 2013年第29期
Thirty pathological y diagnosed patients with grade III-IV primary or recurrent malignant glioma (tumor diameter 3-7 cm) were randomly divided into two groups. The control group underwent conventional radiotherapy and chemotherapy. In the hyperthermia group, primary cases received hyperthermia treatment, and patients with recurrent tumors were treated with hyperthermia in com-bination with radiotherapy and chemotherapy. Hyperthermia treatment was administered using a 13.56-MHz radio frequency hyperthermia device. Electrodes were inserted into the tumor with the aid of a CT-guided stereotactic apparatus and heat was applied for 1 hour. During 3 months after hyperthermia, patients were evaluated with head CT or MRI every month. Gliomas in the hyper-thermia group exhibited growth retardation or growth termination. Necrosis was evident in 80%of the heated tumor tissue and there was a decrease in tumor diameter. Our findings indicate that ra-dio frequency hyperthermia has a beneficial effect in the treatment of malignant glioma.
作者： 刊期： 2013年第29期
