不同环氧合酶-2抑制剂治疗大鼠脑外伤早期炎症实验观察

目的 :探讨环氧合酶-2(COX-2)抑制剂尼美舒利(Nimesulide)和吲哚美辛(Indom-ethacin)在减轻脑外伤早期炎症反应中的治疗作用。方法:采用液压冲击法建立实验动物脑创伤模型,每间隔12h腹腔注射尼美舒利和吲哚美辛,分别于伤后24、48、72和96h应用RT-PCR和Western-Blot法检测环氧合酶-2mRNA和蛋白水平,ELISA法检测前列腺素E2(PGE2)水平,实验动物给予以神经功能评分。结果:选择性COX-2抑制剂尼美舒利在降低脑外伤早期环氧化酶-2mRNA及蛋白质合成方面强于非选择性COX-2抑制剂吲哚美辛,但二者在降低PGE2水平以及改善神经功能方面无显著性差异(P>0.05)。结论:COX-2抑制剂尼美舒利和吲哚美辛在脑外伤早期治疗中的抗炎作用相当,但吲哚美辛的抗炎机制可能涉及到更多的炎症通路。

Nicotine enhances migration and invasion of human esophageal squamous carcinoma cells which is inhibited by nimesulide

AIM： To study the effect of nicotine on the migration and invasion of human esophageal squamous carcinoma cells and to investigate whether nimesulide can inhibit the effect of nicotine.METHODS： The esophageal squamous carcinoma cell line （TE-13） was treated with different concentrations of nicotine （100 μg/mL and 200 μg/mL） or 200 μg/mL nicotine plus 100 μmol/L nimesulide. Cell migration and invasion were measured using migration and invasion chamber systems. COX-2 expression was determined by Western blotting. Matrix metalloproteinase-2 （MMP-2） was analyzed by zymography and ELISA.RESULTS： Nicotine （100 μg/mL, 200 μg/mL） enhanced TE-13 cells migration and invasion, and increased the protein expression of COX-2 and the activity of MMP-2. Nicotine （200 μ/mL） stimulated TE-13 cells migration and invasion which were partly blocked by nimesulide. This was associated with decreased protein expression of COX-2 and decreased activity and protein expression of MMP-2. CONCLUSION： Nicotine enhances the migration and invasion of the esophageal squamous carcinoma cell line, and nimesulide partly blocks the effect ofnicotine-enhanced esophageal squamous carcinoma cell migration and invasion.

5-aminosalicylic acid in combination with nimesulide inhibits proliferation of colon carcinoma cells in vitro

AIM: To investigate the effects of 5-aminosalicylic acid (5-ASA) in combination with nimesulide on the proliferation of HT-29 colon carcinoma cells and its potential mechanisms. METHODS: Inhibitory effects of drugs (5-ASA,nimesulide and their combination) on HT-29 colon carcinoma cells were investigated by thiazolyl blue tetrazolium bromide (MTT) assay. Cellular apoptosis and proliferation were detected by TUNEL assay and immunocytochemical staining,respectively. RESULTS: Pretreatment with 5-ASA or nimesulide at the concentration of 10-1000 μmol/L inhibited proliferation of HT-29 colon carcinoma cells in a dose-dependent manner in vitro (t = 5.122,P < 0.05; t = 3.086,P < 0.05,respectively). The inhibition rate of HT-29 colon carcinoma cell proliferation was also increased when pretreated with 5-ASA (100 μmol/L) or nimesulide (100 μmol/L) for 12-96 h,which showed an obvious time-effect relationship (t = 6.149,P < 0.05; t = 4.159,P < 0.05,respectively). At the concentration of 10-500 μmol/L,the apoptotic rate of HT-29 colon carcinoma cells significantly increased (t = 18.156,P < 0.001; t = 19.983,P < 0.001,respectively),while expression of proliferating cell nuclear antigen (PCNA) was remarkably decreased (t = 6.828,P < 0.05; t = 14.024,P < 0.05,respectively). 5-ASA in combination with nimesulide suppressed the proliferation of HT-29 colon carcinoma cells more than either of these agents in a dose-dependent and time-dependent manner (t = 5.448,P < 0.05; t = 4.428,P < 0.05,respectively). CONCLUSION: 5-ASA and nimesulide may inhibit the proliferation of HT-29 colon carcinoma cells and coadministration of these agents may have additional chemopreventive potential.

The Effect of Nimesulide on the Expression of NF-κB,Bcl-2 and Bax in the Human Gastric Cancer SGC-7901 Cell Line

OBJECTIVE To investigate whether nimesulide can suppress tumor growth and induce apoptosis in SGC-7901 gastric cancer cells and to explore the molecular mechanism involved. METHODS SGC-7901 cells were cultured in RPMI 1640 medium containing different concentrations of nimesulide （0,12.5, 50, 100, 200, 400 μmol/L）. The MTT assay, morphological observation, electron microscopy （EM）, immunohistochemical analysis and Western blot analysis were employed to investigate the effects of nimesulide on the SGC-7901 cells and to explore possible related molecular mechanisms. RESULTS Nimesulide inhibited the growth of SGC-7901 cells and elicited typical apoptotic morphologic changes. Nimesulide also decreased NF-κB and Bcl-2 expression, but increased the level of the Bax protein. The positive rate of Bcl-2 protein expression at 0, 50, 100 and 200 μmol/L of nimesulide was 58.3±14.0%, 50.2±9.9%, 32.8±5.0% and 22.7±5.5% respectively based on immunohistochemical staining. The positive rate of Bax protein expression was 22.0±5.7%, 29.2±6.5%, 42.7±5.9% and 74.5±9.1% and the NF-κB expression was 74.2±10.9%, 61.8±7.6%, 36.7±10.9% and 17.5±12.3%, Significant differences were found between so μmol/L and 100 μmol/L and 200μmol/L. Western blot analysis also showed that the expression of NF-κB was decreased. CONCLUSION Nimesulide suppresses tumor growth and induces apoptosis by inhibiting NF-κB expression, which may be related to the overexpression of Bax relative to Bcl-2 expression.

A simple and robust HPLC-MS method for the quantitative determination of nimesulide in human plasma and its application to bioequivalence study in Chinese volunteers

A rapid and sensitive high performance liquid chromatography-mass spectrometry （HPLC-MS） method for the quantification of nimesulide in human plasma was developed and validated. Sample aliquots of 100μL were extracted by one-step liquid-liquid extraction after addition of hydrochlorothiazide as the internal standard （IS）. Analytes were separated on a reverse phase C18 column using methanol-water （84：16, v/v） as the mobile phase and detected by a single quadrupole mass spectrometer in selected ion monitoring （SIM） negative mode. Monitored m/z values for nimesulide and IS were 307.00 and 295.90, respectively. The overall run time was 4.2 min. Validation experiments demonstrated good precision and accuracy over a wide concentration range of 20.0-7000 ng/mL with a lower limit of quantification （LLOQ） at 20.0 ng/mL. No interference by endogenous substances or matrix effect was observed. Average extraction recoveries for nimesulide and IS were all greater than 84.4%. The assay was successfully applied to a bioequivalence study of nimesulide dispersible tablets in Chinese male volunteers after oral administration.

Optimization and characterization of nimesulide bilayer tablets by response surface methodology

The objectives of this present investigation were to develop and formulate nimesulide bilayer tablets by using different polymer combinations and fillers, to optimize the formulations for different drug release variables by orthogonal design and central composite design-surface methodology and to evaluate drug release pattern of the optimized product. The bilayer tablet containing a fast release layer（FRL） and a sustained release layer（SRL） provided an initial burst release of nimesulide, followed by the sustained release for a period of time. The optimal formulation obtained was as follows：（I） the formulation of FRL： nimesulide, 50 mg; lactose, 92 mg; starch, 22 mg; CCMC-Na, 14 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; magnesium stearate, 0.9 mg; and iron oxide red, 0.1 mg; and（II） the formulation of SRL： nimesulide, 150 mg; HPMC K100LV, 26 mg; HPMC K4M, 33 mg; lactose, 54 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; and magnesium stearate, 0.9 mg. According to the optimal formulation, the biphasic type of release was identified. The in vitro drug dissolution from the bilayer tablets was sustained for about 16 h after releasing 15% of drug in the first 10 min. The developed nimesulide bilayer tablets with improved efficacy can perform therapeutically better than the conventional tablets.

Protective effects of selective and non-selective cyclooxygenase inhibitors in an animal model of chronic stress

Objective Cyclooxygenase isoenzyme is known to be expressed in different regions of brain, and is mainly used for the treatment of pain and inflammation. Recently, it is proposed that cyclooxygenase isoenzyme may also play a key role in the pathophysiology of various brain-related disorders. The present study was aimed to explore the protective effect of cyclooxygenase inhibitors on stress by using an animal model of chronic stress. Methods The animals were forced to swim individually for a period of 6 min every day for 15 d. Then, the behavior （locomotor activity, anxiety and memory） and biochemical （lipid peroxidation, nitrite level, reduced glutathione, and catalase） alterations were assessed. Results Forced swimming for 15 d caused impaired locomotor activity, anxiety-like behavior and decreased percentage of memory retention, as compared to na？ve mice （without chronic fatigue treatment）. Biochemical analysis revealed significant increases in lipid peroxidation and nitrite level, while levels of reduced glutathione and catalase activity were both decreased. Chronic treatment with naproxen （14 mg/kg, i.p.）, rofecoxib （5 mg/kg, i.p.）, meloxicam （5 mg/kg, i.p.）, nimesulide （5 mg/kg, i.p.） and valdecoxib （10 mg/kg, i.p.） significantly attenuated these behavioral and biochemical （oxidative damage） alterations in chronic-stressed mice. Conclusion The cyclooxygenase inhibitors could be used in the management of chronic fatigue-like conditions.