[Age-dependent expression of HSP90 in the hippocampus of APP/PS1 mice].

The present study aims to observe the change in expression of heat shock protein 90 (HSP90) along with amyloid-ß (Aß) and phosphorylated Tau (p-Tau) protein levels in the hippocampus tissue of Alzheimer's disease (AD) transgenic animal model with age. APP/PS1 transgenic mice at age of 6-, 9- and 12-month and C57BL/6J mice of the same age were used. The cognitive abilities of these animals were evaluated using a Morris water maze. Western blot or immunohistochemistry was used to detect the expressions of HSP90 and Aß1-42, as well as the phosphorylation levels of Tau protein in the hippocampus. The hsp90 mRNA levels and the morphology and number of cells in the hippocampus were detected with real-time quantitative polymerase chain reaction (qRT-PCR) and Nissl staining, respectively. The results showed that compared with C57BL/6J mice of the same age, HSP90 and hsp90 mRNA expression were decreased (P < 0.05 or P < 0.01), while Aß1-42 and p-Tau protein levels were increased (P < 0.05 or P < 0.01) in the hippocampal tissue of APP/PS1 transgenic mice. Meanwhile, the decrease in HSP90 and hsp90 mRNA expression (P < 0.05 or P < 0.01), the increase in Aß1-42 and p-Tau levels (P < 0.01 or P < 0.05) in hippocampal tissue and the reduction in behavioral ability showed a progressive development with the advancing of age in the APP/PS1 transgenic mice. In conclusion, in the hippocampal tissue of APP/PS1 mice, the decrease in HSP90 expression and the increase in Aß1-42 and p-Tau levels together with the decline of their cognitive ability are age-dependent.

[Time dependent expression profiling of PTK2B and its relationship with Aß, Tau and LRP-1 in hippocampus and blood of APPswe/PS1dE9 double-transgenic mouse].

Objective: To uncover the time-dependent expression pattern of ptk2b gene and ptk2b-encoded protein, protein tyrosine kinase 2 beta(PTK2B), in the brain tissues of transgenic animal models of Alzheimer's disease (AD) and its relationship with the levels of Aß1-42, phosphorylation of Tau (p-Tau) and low density lipoprotein receptor-related protein-1(LRP-1) in blood and brain tissues. Methods: In this study, 5-, 10- and 15-month-old APPswe/PS1dE9 double-transgenic mice harboring the genotype of AD confirmed by the gene test were divided into the 5-, 10- and 15-month-old experiment groups, and simultaneously, age-matched C57BL/6J mice were placed into the corresponding control groups, with 8 mice in each group. All mice were subjected to the Morris Water Maze for test of cognitive and behavioral ability. Expression profiles of PTK2B, Aß1-42, p-Tau/Tau and LRP-1 in the hippocampus or blood of mice were quantified by using the immunohistochemistry staining, Western blot or enzyme-linked immunosorbent assay (ELISA), while the mRNA expression of ptk2b in the hippocampus was quantified by using the real-time quantitative polymerase chain reaction (qRT-PCR). Results: Results of experiment groups demonstrated that as mice aged, the expression levels of PTK2B, ptk2b mRNA, Aß1-42 and p-Tau/Tau in the hippocampus were increased, and the expression of LRP-1 was decreased gradually. While in the blood, the level of Aß1-42 was decreased, and the cognitive and behavioral ability was decreased in an age-dependent manner (all P＜ 0.05). However, comparisons among the control groups, only the age-dependent downregulation of LRP-1 were observed in hippocampus(P＜0.05), but other indicators had no significant differences (P＞0.05). Conclusion: In the hippocampus of APP/PS1 double-transgenic mice, the expressions of PTK2B, Aß1-42 and p-Tau/Tau are upregulated, LRP-1 is downregulated, while cognitive and behavioral ability is decreased, and such changes are presented in a time-dependent manner.

[PTK2B affects the levels of Aß in blood and brain and behavioral functions via targeting LRP-1 transporter in Aß-induced cognitive dysfunction mice].

The aim of the present study was to explore the correlation between ptk2b/PTK2B (protein tyrosine kinase 2 beta, a ptk2b-encoded protein) and the level of low density lipoprotein receptor-related protein-1 (LRP-1), as well as to uncover the relationship between the changes in beta amyloid protein (Aß) levels in blood and brain and the expression of ptk2b in Aß-induced cognitive dysfunction mice. A total of 64 3-month-old C57BL/6J mice were divided randomly into the experimental group and control group. All mice underwent the intracerebroventricular (i.c.v.) intubation. Mice in the experimental group received the i.c.v. infusion of oligomeric Aß1-42 (0.1 µg/µL, 3.6 µL) to construct the cognitively impaired models, and three days later, those mice were further injected with PF431396 (an inhibitor of PTK2B, 15 µg/mL, Aß + PF group), phorbol-12-myristate-13-acetate (PMA, an agonist of PTK2B, 18.75 µg/mL, Aß + PMA group), RAP (an inhibitor of LRP-1, 0.2 µg/mL, Aß + RAP group) or normal saline (Aß + NS group). For mice in the control group, they underwent the i.c.v. infusion of NS, and 3 days later, they were additionally injected with PF431396 (PF group), PMA (PMA group), RAP (RAP group) or NS (NS group) in the volume of 2 µL. One week later, all mice were subjected to the determination of behavioral function in Morris water maze and the measurement of expression of Aß1-42, LRP-1 and PTK2B in blood and hippocampus using immunohistochemistry (IHC) staining, enzyme-linked immunosorbent assay (ELISA) and Western blot, and the measurement of mRNA expression of ptk2b in hippocampus using qRT-PCR. The results showed that the infusion of Aß induced an increase of Aß1-42 level in hippocampus and a decrease in blood, with the down-regulation of LRP-1 protein expression in hippocampus and up-regulation of mRNA and protein expression of ptk2b in hippocampus. For cognitively impaired mice, intervention of PF431396 caused the down-regulation of protein and mRNA expression of ptk2b in the hippocampus, while LRP-1 in hippocampus was up-regulated with a decrease in the level of Aß1-42 in hippocampus and an increase in the level of Aß1-42 in the blood, as well as significant improvement in cognitive function, while the administration of PMA resulted in the opposite changes. Moreover, the administration of RAP triggered the down-regulation of LRP-1 expression in hippocampus and an increase in the level of Aß1-42 in hippocampus and a decrease in the level of Aß1-42 in blood, with the deterioration of the behavioral functions, while protein and mRNA expression of ptk2b in hippocampus showed no evident changes. These results suggest that, in cognitively impaired mice, PTK2B, possibly via down-regulating LRP-1, increases the Aß1-42 level in brain, but decreases the Aß1-42 level in blood, thereby deteriorating the cognitive and behavioral functions of mice.

Histone deacetyltase 6 modulates amyloid ß-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta.

The aim of this study was to investigate the effects of histone deacetyltase (HDAC) 6 on the functional and pathological changes of the amyloid beta (Aß)-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta (PTK2B). Ninety Sprague-Dawley rats were randomly divided into nine groups, consisting of five experimental groups and four control groups. In five experimental groups, Aß1-42 was infused intracerebroventricularly and 3 days later, rats in each group were infused intracerebroventricularly with tubastatin A hydrochloride (TSA), the histone deacetyltase 6 (HDAC6)-specific inhibitor (Aß + TSA group), theophylline, the HDACs agonist (Aß + theophylline group), PF431396, the PTK2B inhibitor (Aß + PF group), the combination of PF431396 and theophylline (Aß + PF + theophylline group) and normal saline (Aß + normal saline group), respectively. Rats in four control groups took normal saline that was equivalent to the volume of Aß1-42, and 3 days later, TSA group, theophylline group, PF431396 (PF group), or normal saline group was given at a volume of 5 µL for rats in each group. Our results showed that HDAC6 may not only lead to the deterioration of learning and memory abilities but also elevate the levels of Aßo and Tau phosphorylation in Aß-induced cognitive dysfunction rats via up-regulating PTK2B.

Histone deacetylase-6 modulates amyloid beta-induced cognitive dysfunction rats by regulating PTK2B.

The aim of this study was to investigate the effects of histone deacetylase-6 (HDAC6) on the functional and pathological changes of the amyloid beta (Aß)-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta (PTK2B). Ninety Sprague Dawley rats were randomly divided into nine groups, consisting of five experimental groups and four control groups. In five experimental groups, Aß1-42 was infused intracerebroventricularly and 3 days later, rats in each group were infused intracerebroventricularly with tubastatin A hydrochloride (TSA), the HDAC6-specific inhibitor (Aß + TSA group), theophylline, the HDACs agonist (Aß + Theo group), PF431396 (PF), the PTK2B inhibitor (Aß + PF group), the combination of PF and theophylline (Aß + PF + Theo group), and normal saline (Aß + normal saline group), respectively. Rats in four control groups took normal saline that was equivalent to the volume of Aß1-42, and 3 days later, TSA (TSA group), theophylline (Theo group), (PF group, or normal saline group) was given at a volume of 5 µL for rats in each group. Our results showed that HDAC6 may not only lead to the deterioration of learning and memory abilities but also elevate the levels of Aßo and Tau phosphorylation in Aß-induced cognitive dysfunction rats via upregulating PTK2B.

[Temporal and spatial changes of α7nAChR and nNOS in cerebral cortex and hippocampus of Aß-induced cognitive dysfunction rats].

The present study was to explore the temporal and spatial distributions and variations of α7 nicotinic acetylcholine receptor (α7nAChR) and neuronal nitric oxide synthetase (nNOS) in cerebral cortex and hippocampus of Aß-induced cognitive dysfunction rats. Sixty Sprague-Dawley (SD) rats were randomly divided into six groups. Three experimental groups were intracerebroventricularly (i.c.v.) injected with condensed-amyloid beta peptides 1-42 (Aß1-42, 2.5 µg/µL, 4 µL) and were observed on day 7 (7 d Aß group), day 14 (14 d Aß group) and day 21 (21 d Aß group), respectively. Three control groups were i.c.v. injected with equivalent volume of normal saline and observed at the same time points as the experimental groups. The learning and memory abilities of rats were tested with Y-maze; the locations and protein expression levels of α7nAChR and nNOS in cerebral cortex and hippocampal CA1, CA3, DG regions were measured by immunohistochemistry and Western blot, respectively. The result showed that, compared with the control groups, the three experimental groups exhibited decreased learning and memory behavioral abilities, and down-regulated expressions of nNOS and α7nAChR in prefrontal cortex and hippocampal regions, especially in superficial layer of prefrontal cortex and hippocampal CA3 region. Comparisons among the three experimental groups showed that the inhibitory effects of Aß on the abilities of learning and memory and the expressions of α7nAChR and nNOS in prefrontal cortex and hippocampus were time dependent. The results suggest that the coincident declines of α7nAChR and nNOS in prefrontal cortex and hippocampus may be the foundations of the cognitive dysfunction.

[The synergetic effects of nitric oxide and nicotinic acetylcholine receptor on learning and memory of rats].

The aim of the present study is to explore the interaction of nitric oxide (NO) and nicotinic acetylcholine receptor (nAChR) on learning and memory of rats. Rats were intracerebroventricularly (i.c.v.) injected with L-arginine (L-Arg, the NO precursor) (L-Arg group) or choline chloride (CC, an agonist of α7nAChR) (CC group), and with combined injection of L-Arg and CC (L-Arg+CC group), and methyllycaconitine (MLA, α7nAChR antagonist) or N(ω)-nitro-L-arginine methylester (L-NAME, nitric oxide synthase inhibitor) i.c.v. injected first and followed by administration of L-Arg combined with CC (MLA+L-Arg+CC group or L-NAME+L-Arg+CC group), respectively, and normal saline was used as control (NS group). The learning and memory ability of rats was tested with Y-maze; the level of NO and the expressions of neuronal nitric oxide synthase (nNOS) or α7nAChR in hippocampus were measured by NO assay kit, immunohistochemistry or Western blot. The results showed that compared with L-Arg group or CC group, the rats' learning and memory behavioral ability in Y-maze was observably enhanced and the level of NO, the optical density of nNOS-like immunoreactivity (LI) or α7nAChR-LI in hippocampus were significantly increased in L-Arg+CC group; Compared with L-Arg+CC group, the ability of learning and memory and the level of NO as well as the expressions of nNOS-LI or α7nAChR-LI were obviously decreased in MLA+L-Arg+CC group or in L-NAME+L-Arg+CC group. In conclusion, i.c.v. administration of L-Arg combined with CC significantly improved the action of the L-Arg or CC on the content of NO and the nNOS or α7nAChR expressions in hippocampus along with the learning and memory behavior of rats; when nNOS or α7nAChR was interrupted in advance, the effects of L-Arg combined with CC were also suppressed. The results suggest that there are probably synergistic effects between NO and nAChR on learning and memory.

Effects of L-arginine and N(ω)-nitro-L-arginine methylester on learning and memory and α7 nAChR expression in the prefrontal cortex and hippocampus of rats.

Nitric oxide (NO) is a novel type of neurotransmitter that is closely associated with synaptic plasticity, learning and memory. In the present study, we assessed the effects of L-arginine and N(ω)-nitro-L-arginine methylester (L-NAME, a nitric oxide synthase inhibitor) on learning and memory. Rats were assigned to three groups receiving intracerebroventricular injections of L-Arg (the NO precursor), L-NAME, or 0.9% NaCl (control), once daily for seven consecutive days. Twelve hours after the last injection, they underwent an electric shock-paired Y maze test. Twenty-four hours later, the rats' memory of the safe illuminated arm was tested. After that, the levels of NO and α7 nicotinic acetylcholine receptor (α7 nAChR) in the prefrontal cortex and hippocampus were assessed using an NO assay kit, and immunohistochemistry and Western blots, respectively. We found that, compared to controls, L-Arg-treated rats received fewer foot shocks and made fewer errors to reach the learning criterion, and made fewer errors during the memory-testing session. In contrast, L-NAME-treated rats received more foot shocks and made more errors than controls to reach the learning criterion, and made more errors during the memory-testing session. In parallel, NO content in the prefrontal cortex and hippocampus was higher in L-Arg-treated rats and lower in L-NAME rats, compared to controls. Similarly, α7 nAChR immunoreactivity and protein expression in the prefrontal cortex and hippocampus were higher in L-Arg-treated rats and lower in L-NAME rats, compared to controls. These results suggest that the modulation of NO content in the brain correlates with α7 nAChR distribution and expression in the prefrontal cortex and hippocampus, as well as with learning and memory performance in the Y-maze.

Effects of multiple intrathecal administration of L-arginine with different doses on formalin-induced nociceptive behavioral responses in rats.

OBJECTIVE: To investigate the effects of nitric oxide (NO) with different doses on modulation of inflammatory pain, and its possible mechanisms. METHODS: NO precursor L-arginine (L-Arg) was intrathecally administered in rats at a dose of 10 microg per day (low dose group) or 250 microg per day (high dose group) for a succession of 4 d. Normal saline was applied as a control. Then the rats were subcutaneously injected with formalin (100 microL, 2%) into the right hind paw, and the nociceptive behavioral responses within 1 h were observed. At 4 h after formalin injection, neuronal NO synthase (nNOS) and c-Fos expression in spinal dorsal horn was examined with immunocytochemistry method. RESULTS: The subcutaneous injection of formalin evoked biphasic behaviors of licking or biting the injected paw. There was no difference in acute phase of formalin test among the 3 groups, while in tonic phase, the licking and biting time, and the protein levels of nNOS and c-Fos in spinal dorsal horn were significantly decreased in low dose group and increased in high dose group, compared with those in control group. CONCLUSION: These results suggest that multiple administration of NO with different doses may produce different effects. On one hand, the low dose of NO can induce antinociception. On the other hand, the high dose of NO can induce pronociception.

[Amplification and specific expression of T-bet gene in nasal NK/T cell lymphoma].

OBJECTIVE: To investigate the specific genetic alterations in nasal NK/T cell lymphoma (N-NK/T-L) and the significance thereof. METHODS: Restriction landmark genomic scanning (RLGS) was performed on the specimen of a case of N-NK/T-L and the peripheral blood leukocytes of the same case. The RLGS image was analyzed with the Virtual genome scan (VGS) software so as to discover abnormality of T-bet gene. The discovered abnormal gene underwent cloning and preparation of probes. Southern blotting and dot blotting were performed on 3 cases of fresh N-NK/T-L tumor tissues and the genome of the case of peripheral blood lymphocytes. The expression of the T-bet (T-box expressed in T cell) gene in the tissue sections of 20 cases of N-NK/T-L, 17 cases of B cell lymphoma (BCL), 3 cases of normal spleen, and 5 cases of chronic nasopharyngitis was detected by in situ hybridization. RESULTS: RLGS combined with VGS revealed a genomic alteration in the T-bet gene and consequent Southern and dot blotting confirmed this genomic alteration in the N-NK/T-L cells. In situ hybridization showed that the T-bet mRNA expression rate of the N-NK/T-L cells was 90.0% (18/20), significantly higher than that of the BCL (11.8%, 2/17, P < 0.01). T-bet mRNA expression was not detected in the normal spleen and chronic nasopharyngitis tissues. CONCLUSION: The amplification and over-expression of the T-bet gene may play a role in the development of N-NK/T-L. The potential value of over-expression of T-bet gene in diagnosis of N-NK/T-L is worth further investigating.

[MK-801 suppresses dynorphin A (1-17)-induced facilitation of nociceptive responses to formalin in rats].

To explore the facilitation of nociceptive response by dynorphin (Dyn ) A in a model of formalin test in rats, the effects of single intrathecal injection (i.t.) of normal saline (NS), MK-801 (antagonist of NMDA receptor), naloxone (antagonist of opioid receptor), or Dyn A (1-17) were observed, and the effects of i.t. MK-801 or naloxone followed by i.t. Dyn A (1-17) were observed as well. The nociceptive licking and biting induced by injection of formalin exhibited two phases. The first phase lasted for a relatively short period of 3-9 min, and the second phase lasted for a relatively longer period after a 3 to 6- min quietness. The results showed that there were no differences in the first phase in all groups; however, there were differences in the second phase as follows: (1) the duration of nociceptive response was significantly increased in Dyn A (1-17) group (489.5+/-22.5 s) as compared to that of NS group (344.7+/-12.9 s), MK-801 group (331.4+/-20.7 s) or naloxone group (352.5+/-18.4 s) (P<0.01 in three cases); (2) the duration of nociceptive response was significantly shortened in MK-801 plus Dyn A (1-17) group (285.7+/-19.4 s) as compared to that of Dyn A (1-17) group (P<0.01), but there were no significant differences as compared to that of MK-801 group; and (3) there was no significant difference in the second phase between naloxone plus Dyn A (1-17) group (473.8+/-17.8 s) and Dyn A (1-17) group, but the duration of nociceptive response was longer than that of NS group or naloxone group (P<0.01 in both). The results obtained suggest: (1) at the spinal cord, Dyn A (1-17) facilitates nociceptive responses; (2) NMDA receptors, but not opioid receptors, are possibly involved in the nociception by Dyn A (1-17).