RESUMO
Objective To evaluate the role of adenosine A1 receptors in hippocampal neurons in the cognitive dysfunction caused by isoflurane anesthesia in aged mice.Methods Sixteen male adenosine A1 receptor gene knockout homozygote mice (gene knockout mice) and 16 male wild-type mice,aged 18-22 months,weighing 27-32 g,were studied.Each type of mice was randomly divided into 2 groups (n=8 each) using a random number table:control group (group C) and isoflurane anesthesia group (group Ⅰ).Mice inhaled 1.4％ isoflurane in 100％ O2 for 2 h in group Ⅰ,and 100％ O2 for 2 h in group C.All the mice underwent Morris water maze test at 24 h after isoflurane or O2 inhalation.After the test,the mice were sacrificed and the hippocampal tissues were harvested to determine the number of β-amyloid1-42 (Aβ1-42) plaques (using immunohistochemistry) and expression of phosphorylated tau (p-tau) protein,and 2B subunit-containing N-methyl-D-aspartate receptors (NR2B) (by Western blot analysis).Results Compared with group C of wild type mice,the escape latency was significantly prolonged,the number of Aβ1-42 plaques was enlarged,the expression of p-tau protein was up-regulated,and the expression of N R2B was down-regulated in group Ⅰ of wild type mice.Compared with group Ⅰ of wild type mice,the escape latency was significantly shortened,the number of Aβ1-42 plaques was decreased,the expression of p-tau protein was down-regulated,and the expression of NR2B was up-regulated in group Ⅰ of gene knockout mice.There was no significant difference in the parameters mentioned above between group Ⅰ and group C of gene knockout mice.Conclusion Adenosine A1 receptors in hippocampal neurons mediate isoflurane anesthesia-induced cognitive dysfunction in aged mice,and the mechanism may be related to promotion of deposition of Aβ,phosphorylation of tau protein and inhibition of activities of NR2B.
RESUMO
OBJECTIVE To investigate the effect of curcumin on proliferation of neural stem cells (NSCs) of rats and the mechanism. METHODS NSCs derived from the forebrain of rat E15 embryos were cultured in vitro and identified by neuroepithelial stem cell protein ( nestin and SOX2) staining. NSCs were treated with curcumin 0.1, 0.5, 2.5, 12.5 and 62.5 μmol.L-1 for 24 h, respectively. The cyto-toxicity was estimated by measuring the release of lactate dehydrogenase(LDH). Cell viability and prolif-eration were analyzed respectively by MTT and BrdU assay. The mRNA expression levels of glucocorti-coid receptor (GR), Stat3, Notch1 and p21 were detected by qRT-PCR. The protein expression levels of total GR, Stat3 and phosphorylated Stat3 were measured by Western blotting. RESULTS The primary neural stem cells were identified as NSCs. Curcumin 12.5 and 62.5 μmol.L-1 had cell cytotoxicity( P<0.05). Cell viability assay indicated that curcumin 0.5 and 2.5 μmol.L-1 enhanced NSCs viability( P <0.05), but in 62.5 μmol.L-1 group the cell cytotoxicity was inhibited(P<0.05). Curcumin 0.1, 0.5 and 2.5 μmol.L-1 increased NSCs proliferation ( P < 0. 05), whereas 12. 5 and 62. 5 μmol.L-1 caused a decrease in NSCs proliferation(P<0.05). The mRNA expression level of GR in 0.5 μmol.L-1 group was significantly reduced( P<0.05). Western blotting analysis revealed that the protein expression of GR, Stat3 and p-Stat3 was inhibited by curcumin in 0.5 μmol.L-1 group(P<0.05). CONCLUSION Curcumin stimulates NSCs proliferation, possibly by inhibiting GR mRNA and related protein expression.
