Quantitative determination of 12-hydroxyeicosatetraenoic acids by chiral liquid chromatography tandem mass spectrometry in a murine atopic dermatitis model

Atopic dermatitis, one of the most important skin diseases, is characterized by both skin barrier impairment and immunological abnormalities. Although several studies have demonstrated the significant relationship between atopic dermatitis and immunological abnormalities, the role of hydroxyeicosatetraenoic acids (HETE) in atopic dermatitis remains unknown. To develop chiral methods for characterization of 12-HETE enantiomers in a 1-chloro-2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model and evaluate the effects of 12-HETE on atopic dermatitis, BALB/c mice were treated with either DNCB or acetone/olive oil (AOO) to induce atopic dermatitis, after which 12(R)- and 12(S)-HETEs in the plasma, skin, spleen, and lymph nodes were quantified by chiral liquid chromatography-tandem mass spectrometry. 12(R)- and 12(S)-HETEs in biological samples of DNCB-induced atopic dermatitis mice increased significantly compared with the AOO group, reflecting the involvement of 12(R)- and 12(S)-HETEs in atopic dermatitis. These findings indicate that 12(R)- and 12(S)-HETEs could be a useful guide for understanding the pathogenesis of atopic dermatitis.

Influence of the 15-HETE on cytosolic [ Ca2+] i of the rabbit pulmonary artery smooth muscle cells

Extracellular Ca2+ influx was blocked by L-type Ca2+ channel blocker nifedipine to observe the effects of 15-hydroxyeicosatetraenoic acid on the constriction of rabbit pulmonary artery rings and on the changes of Ca2+ level in the rabbit pulmonary artery smooth muscle cells, and further to investigate the mechanism of the calcium mobilization induced by the 15-HETE under hypoxic conditions. The effect of extracellular Ca2+ on tension of the rabbit PA rings was also studied. Nifedipine (10 µ mol/L) had no effect on 1 µ mol/L 15-hydroxyeicosatetraenoic acid induced vasoconstriction under normoxic and hypoxic conditions. Intracellular Ca2+ increased markedly in the 15-HETE group (cells were exposed to 1 µ mol/L 15-HETE for 8 min during culture) compared to the control group (P < 0.05). The study demonstrated that the 15-HETE could induce the elevation of Ca2+ in the pulmonary artery smooth muscle cells and the elevated calcium came from the release of the intracellular calcium.

The anti-inflammatory effect of total flavonoids isolated from Platychadus orientalis and its mechanism / 中国药理学通报

AIM To investigate the anti-inflammatory eff ec t of total flavonoids isolated from Platychadus orientalis and its mechanism . METHODS The inflammatory models in mice and swelling of rats hind paws were induced by dimethylbenzene and carrageenan respectivel y. The biosynthesis of leukotriene and ?-glucuronidase release in the cells we re measured by HPLC and fluorescence spectrophotometer respectively. RES ULTS Total flavonoids isolated from Platychadus orientalis remarkably inhibited the ear edema induced by dimethylbenzene in mice at the dose of 12.5 ～50.0 mg?kg -1 and the swelling of rats hind paws induced by carrageenan at the dose of 25.0～50.0 mg?kg -1 . Total flavonoids at final concentrati on of 5.0～125.0 mg?L -1 inhibited 5-HETE and LTB 4 synthesis by 30.5%～ 87.3% and 27.8%～84.3% respectively. In comparision with controls, Total flavono ids at final concentration of 5.0～45.0 mg?L -1 inhibited ?-glucuronidas e release by 13.4%～32.2%. CONCLUSION Total flavonoids isolated f rom Platychadus orientalis has an anti-inflammatory effect which may be rel ated to inhibiting 5-HETE and LTB 4 production and ?-glucuronidase release.

Simultaneous HPLC analysis of arachidonic acid metabolites in biological samples with simple solid phase extraction

A reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed to analyze the metabolites of arachidonic acid based on the specificities of ultraviolet absorption of these various metabolites and is sensitive to the nanogram level. This procedure makes it possible to extract complex mixtures of eicosanoids efficiently with a single step and to analyze them simultaneously by RP-HPLC from biological samples using octadesylsilyl silica extraction column and PGB2 as an internal standard. The cyclooxygenase, products (prostaglandin (PG)D2, PGE1, PGE2, PGF1alpha, PGF2alpha, 6-keto-PGF1alpha, and thromboxane B2 (TXB2)) and lipid peroxidation product, isoprostanes, of arachidonic acid were monitored by one isocratic HPLC system at 195 nm wavelength. The lipoxygenase products (leukotriene(LT)B4, LTC4, LTD4, and 5-hydroxyeicosatetraenoic acid (5-HETE), 12-HETE, 15-HETE) were measured by another isocratic HPLC system at 280 nm for LTs and 235 nm for HETEs. This method provides a simple and reliable way to extract and assess quantitatively the final arachidonic acid metabolites.

Advances in research on the mechanism of hypoxic pulmonary hypertension:role of 15-LO/15-HETE / 中国药理学通报

Hypoxic pulmonary hypertension(HPH) is a common disease featured by acute hypoxic pulmonary vasoconstriction(HPV) and chronic hypoxic pulmonary vascular remolding(HPVR) leading to the sustained increasing of pulmonary artery pressure.There are many mediators involved in the HPH but none can illustrate it successfully.Primary work has found 15-lipoxygenase(15-LO) and its catalyzed production 15-hydroxyeicosatetraenoic acid(15-HETE)(from arachidonic acid) are up-regulated in pulmonary vascular when exprosed to hypoxia.And it has been found 15-LO/15-HETE involved in many processes of both the HPV and HPVR,indicating 15-LO/15-HETE may be an important mediator of HPH.Advances research on 15-LO/15-HETE may illustrate the mechanism of HPH,and will give some message in looking for a potential clinical target of HPH.

Changes of LTB4 and 15-HETE in lung of rats with chronic obstructive pulmonary disease and the effects of ipratropium / 重庆医科大学学报

Objective:To investigate the changes of leukotriene B4(LTB4)、15-hydroxyeicosatetraenoic acid(15-HETE)in lung of an animal model with chronic obstructive pulmonary disease(COPD),and the effects of ipratropium.Methods:Thirty-six male Wistar rats were randomized into three groups,Group A(normal controls,group B(COPD),group C(smoking+ipratropium),with 12 rats in each group.Group C receiving inhaling ipratropium 0.025%10ml and once a day for 23 days.Pulmonary functions of the rats were assessed, concen-trations of LTB4 15-HETE in lung tissue were measured by RP-HPLC.Results:The lung functions of FEV0.3/FVC%in COPD rats declined obviously(P0.05). Conclusion:Our results suggest that LTB4 and 15-HETE are involved in airway inflammation in COPD.Ipratropium is effective in decreasing the levels of LTB4 and 15-HETE in lung tissue of COPD rats,and attenuating inflammatory changes of airways.