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A quantitative analysis method for fudosteine in human serum by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry [HPLC-ESI/MS/MS] was established, which shows high sensitivity and selectivity. The mobile phase composition was 75% 20 mM acetic acid and 25% acetonitril, which was pumped at a flow rate of 0.40 mL/ min. The overall chromatographic run time was approximately 7 min. The autosampler was set with an injection volume of 10 microL. The calibration curve was linear in the concentration range of 0.1-15.0 microg/mL. The coefficient of determination [r] was greater than 0.9998. This method has been fully validated and shown to be specific, accurate and precise. The method was simple, rapid and the sample preparation was minimal. It was successfully applied to the analysis of healthy volunteer
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<p><b>OBJECTIVE</b>To investigate the protective effect and action mechanism of petroleum ether extracts from Saussurea involucrate on brain tissues of hypoxia rats under constant pressure and closed conditions.</p><p><b>METHOD</b>The PESI dosage-dependent experiment for hypoxia rats was conducted under constant pressure and closed conditions by intraperitoneally injecting 125, 250, 500 mg x kg(-1) to finalize that the optimum dosage is the high dose of PESI. Afterwards, 90 Wistar rats were randomly divided into the hypoxic model group, the acetazolamide 250 mg x kg(-1) group and the PESI high dose group. Each group was further divided into three subgroups according to different hypoxia times, with 10 rats in each subgroup. Under the same hypoxia and administration conditions, the rats were sacrificed after 0, 3, 6 h respectively. Their brain samples were collected for common pathological observation and immunohistochemical staining of HIF-1alpha. Real-time RT-PCR was used to detect HIF-1alpha, EPO, HO-1 and Caspase-3 gene expressions. And the Western blot assay was adopted to detect HIF-1alpha protein expression.</p><p><b>RESULT</b>The brain tissues of the hypoxia model group were severely damaged with the increase in the hypoxia time. The acetazolamide group and the PESI high does group were damaged in a much lower degree. According to the gene expression and the Western blot assay, high dose of PESI could inhibit HIF-1alpha expression. According to the pure gene expression test, high dose of PESI could increase EPO and HO-1 mRNA expressions, but inhibit Caspase-3 mRNA expression.</p><p><b>CONCLUSION</b>PESI's protective mechanism for brain tissues of hypoxia rats under constant pressure and closed conditions may be related to its effects in inhibiting HIF-1alpha expression, increasing EPO expression and resisting cell apoptosis.</p>