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AIM:To investigate the role of extracellular signal-regulated kinase 5(ERK5) in platelet aggrega-tion in vitro and arterial thrombosis in vivo. METHODS:The expression and phosphorylation levels of ERK5 in human platelet were detected by Western blot. The effects of ERK5 selective inhibitor XMD8-92 on platelet aggregation and dense granule secretion were detected by Chrono-Log aggregometer. The effect of ERK5 on in vivo thrombosis was analyzed using an FeCl3artery thrombosis model. The effects of XMD8-92 on protein kinase B (PKB/Akt) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) phosphorylation levels were determined by Western blot. RESULTS:ERK5 was stably expressed in human platelets and its phosphorylation level increased significantly after platelet activation (P<0.05). XMD8-92,a selective inhibitor of ERK5,inhibited platelet aggregation and dense granule secretion in response to several platelet stimulators (P<0.05). The results of Western blot showed that XMD8-92 inhibited Akt phosphorylation level by down-regulating PTEN Ser370 phosphorylation and enhancing PTEN activity. The pathway was further confirmed u-sing platelet specific PTEN deficiency mice. The first occlusion time was obviously extended in the mice intravenously given XMD8-92 in the FeCl3-induced carotid artery injury model. CONCLUSION:ERK5 plays a role in platelet activation and arterial thrombosis by influencing PTEN and Akt phosphorylation.
RESUMO
<p><b>OBJECTIVE</b>The purpose of this article was to evaluate the influence of cobalt-chromium (Co-Cr) alloy as the material of inner crown on periodontal tissue through detecting the weight of diseased teeth and the concentration of aspartate transaminase (AST) and alkaline phosphatase (ALP) of the gingival crevicular fluid (GCF) after Co-Cr alloy ceramics repairing.</p><p><b>METHODS</b>In this study, thirty cases of clinical diseased teeth were chosen from thirty patients based on patients' consent. Each tooth conformed to the inclusion criteria. All of the thirty teeth were repaired with Co-Cr alloy ceramics according to the indications. Then GCF of each diseased tooth was collected and weighed at the time of the day before prosthesis, the first and third month after repairing respectively in order to detect the concentration of AST and ALP. Furthermore, comparative analysis for different periods was performed after the data statistics.</p><p><b>RESULTS</b>To the weight of GCF and the concentration of AST after the respective comparison of three indexes which was of different periods, numerous of each index increased in accordance with the rule of preoperation, postoperative first month, and postoperative third month (P < 0.05). To the concentration of ALP at three time points, the compared results showed that the preoperative numerous was less than that of third month after operation and there was significant difference between them (P < 0.05). To the weight of GCF and the concentration of AST and ALP, after the respective comparison of three indexes which was the diseased teeth and the contralateral teeth with the same name in the periods of pre-operation, all the differences had no statistical significance (P > 0.05), but all the differences had statistical significance in the periods of postoperative third month (P < 0.05).</p><p><b>CONCLUSION</b>During the next three months after operation, GCF weight, concentration of AST and ALP of diseased teeth was gradually increased after their Co-Cr alloy ceramics crown repairing. This increase is somewhat harmful to periodontal health.</p>