Inhibition of ethanol-induced toxicity by tanshinone IIA in PC12 cells.

AIM: To observe the effects of tanshinone IIA (Tan IIA) on the neurotoxicity induced by ethanol in PC12 cells and to explore its protective role. METHODS: PC12 cell survival was measured by MTT assay. The formation of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release were detected by 2',7'-dichlorofluorescin (DCF) fluorescence and calorimetric method, respectively. The percentage of cell apoptosis was monitored by flow cytometry. The expression of p53 was detected by immuno-fluorescence and flow cytometry. RESULTS: Ethanol significantly impaired the survival of PC12 cells as demonstrated by MTT assay. Ethanol also induced significant ROS formation and increased LDH release. Pre-incubation with Tan IIA in the culture medium significantly reversed these changes. Ethanol caused cell apoptosis and the upregulation of p53 protein. The anti-apoptosis effects of Tan IIA on ethanol-induced toxicity were accompanied by the downregulation of pro-apoptotic p53 protein expression. CONCLUSION: Tan IIA can protect neurons from apoptosis and might serve as a potential therapeutic drug for neurological disorders induced by ethanol.

Effects of complete Freund's adjuvant on immunohistochemical distribution of IL-1beta and IL-1R I in neurons and glia cells of dorsal root ganglion.

AIM: To investigate the effects of complete Freund adjuvant (CFA) on inflammatory hyperalgesia and morphological change of the coexistence of interleukin-1 beta (IL-1beta) and type I IL-1 receptor (IL-1RI) in neurons and glia cells of rat dorsal root ganglion (DRG). METHODS: The pain-related parameters and the expression of IL-1RI and IL-1beta positive neurons and glia cells of DRG in normal saline (NS) and adjuvant-induced arthritic (AA) group were examined with pain behavior assessment methods and immunohistochemical assay, respectively. RESULTS: Five hours, 1 d, and 2 d after intra-articular injection of 50 microL CFA, tactile hyperalgesia induced by CFA was observed in the foot flexion and extension scores of the ipsilateral hindpaw of AA group. Three days after injection, the distribution of IL-1RI/IL-1beta double-stained coexisted neurons and glia cells were observed in ipsilateral DRG of both groups. The number of IL-1beta positive neurons, IL-1RI positive neurons, IL-1beta/IL-1RI double-stained neurons, and IL-1RI positive glia cells in ipsilateral DRG of the AA group were higher than that of NS group (P<0.05 or P<0.01). CONCLUSION: The coexistence of IL-1beta and IL-1RI in neurons and nonneuronal cells suggests an as yet unknown autocrine and/or paracrine function of IL-1beta in the DRG. The function was enhanced in articular arthritis induced by CFA and could play an important role in hyperalgesia under inflammatory conditions.

[The role of p53 binding site on the trans binding of p53 to Hsp90 beta gene].

OBJECTIVE: To investigate the effect of p53 binding site (+31/+60) of hsp90 beta gene on its transcriptional regulation. METHODS: The binding site was first inserted into pBS-SK. After the plasmid annealing and elongation with mutagenic and selective primers, nuclease digestion and bacteria transformation was performed twice to select the positive mutated plasmid. Electrophoretic mobility shift assays (EMSA) was employed to detect the binding of hsp90 beta gene fragment containing mutated p53 binding site and Jurkat cell nuclear extract transfected by p53 expression vector. RESULTS: The sequence analysis profile confirmed a successful mutation of two bases on the core sequence of the second half binding site. EMSA results showed the specific DNA-protein complex band disappeared after the mutation. CONCLUSIONS: The core sequence of p53 binding site plays a key role in the trans binding of p53 to hsp90 beta gene.