咪唑斯汀和氯雷他定抗炎作用的比较研究

目的:检测咪唑斯汀的抗炎活性,探讨咪唑斯汀抗炎症的作用机制。方法:建立花生四烯酸诱导小鼠耳部肿胀的模型,了解咪唑斯汀和氯雷他定对花生四烯酸诱导的耳部肿胀的抑制作用;同时用酶免疫法检测小鼠血液中的白三烯浓度。建立角叉菜胶诱导的大鼠鼠爪肿胀模型,了解咪唑斯汀和氯雷他定对角叉菜胶诱导的炎症的抑制作用。结果:咪唑斯汀可抑制花生四烯酸诱导的耳部水肿,对角叉菜胶诱导的鼠爪水肿无抑制作用;但氯雷他定对两种致炎剂诱导的水肿均无抑制作用。结论:咪唑斯汀具有显著的抗炎作用,其机制是抑制5-脂氧合酶的活性,阻止白三烯的产生而发挥其抗炎活性。     

Prostaglandin and leukotriene synthesis in mouse ears inflamed by arachidonic acid

Topical application of arachidonic acid on mouse ears induces the synthesis of prostaglandin E2 and leukotrienes C4 and D4. The increased tissue levels of these products are quantitated by radioimmunoassay. The identity of the leukotrienes was confirmed by immunoreactivity of reverse-phase high-performance liquid chromatography fractions corresponding to authentic standards. Synthesis of the arachidonic acid metabolites precedes or is coincident with increased vascular permeability resulting in an edematous response, as measured by accumulation of [125I]albumin in the ear after i.v. injection or by tissue wet weight. When applied topically, anti-inflammatory drugs such as BW755C (3-amino-1-(m-[trifluoromethyl]phenyl)2-pyrazoline, indomethacin, and nordihydroguaiaretic acid inhibit edema and modulate the appearance of the arachidonic acid products. The data suggest the coinvolvement of prostaglandin E2 and leukotrienes C4 and D4 as mediators of inflammation in this in vivo model.     

咪唑斯汀抗炎作用的实验研究

目的了解咪唑斯汀的抗炎活性及抗炎机制。方法建立花生四烯酸诱导耳部肿胀的小鼠模型,了解咪唑斯汀对花生四烯酸诱导的耳部肿胀的抑制作用;酶免疫法检测小鼠血液中的白三烯浓度。结果咪唑斯汀可抑制花生四烯酸诱导的小鼠耳部水肿,但氯雷他定和西替利嗪均不能;白三烯可减弱咪唑斯汀在花生四烯酸诱导小鼠耳部水肿中的抗炎作用,但前列腺素不能。结论咪唑斯汀具有抗炎症作用,其机制可能是抑制5-脂氧合酶的活性,阻止白三烯的产生而抑制炎症。     

A novel synthetic vitamin A-like compound (a polyprenoic acid derivative, E-5166) inhibits the release of arachidonic acid stimulated by epidermal growth factor

Little is known about the mechanisms of anti-inflammatory activity of retinoids. A new synthetic vitamin A-like compound (polyprenoic acid derivative, E-5166) has a strong in vitro binding affinity to intracellular binding proteins for acidic retinoids. In order to elucidate the anti-inflammatory activity of E-5166, we studied the effect of E-5166 on the epidermal growth factor (EGF)-stimulated arachidonic acid (AA) release of pig epidermis. E-5166 significantly inhibited the EGF-stimulated AA release and this inhibitory effect of E-5166 required a longer incubation than hydrocortisone did. Furthermore, E-5166 inhibited the EGF-stimulated phosphatidylinositol (PI) turnover of pig epidermis. These results indicate that E-5166 inhibited the EGF-stimulated AA release through the inhibition of the EGF-stimulated PI turnover.     

Topical N-acetyl-S-farnesyl-L-cysteine inhibits mouse skin inflammation, and unlike dexamethasone, its effects are restricted to the application site

N-acetyl-S-farnesyl-L-cysteine (AFC), a modulator of G protein and G-protein coupled receptor signaling, inhibits neutrophil chemotaxis and other inflammatory responses in cell-based assays. Here, we show topical AFC inhibits in vivo acute inflammation induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and arachidonic acid using the mouse ear model of inflammation. AFC inhibits edema, as measured by ear weight, and also inhibits neutrophil infiltration as assayed by direct counting in histological sections and by measuring myeloperoxidase (MPO) activity as a neutrophil marker. In addition, AFC inhibits in vivo allergic contact dermatitis in a mouse model utilizing sensitization followed by a subsequent challenge with 2,4-dinitrofluorobenzene. Unlike the established anti-inflammatories dexamethasone and indomethacin, AFC's action was restricted to the site of application. In this mouse model, both dexamethasone and indomethacin inhibited TPA-induced edema and MPO activity in the vehicle-treated, contralateral ear. AFC showed no contralateral ear inhibition for either of these end points. A marginally significant decrease due to AFC treatment was seen in TPA-induced epidermal hyperplasia at 24 hours. This was much less than the 90% inhibition of neutrophil infiltration, suggesting that AFC does not act by directly inhibiting protein kinase C.     

Characteristics and modulation of dithranol (anthralin)-induced skin irritation in the mouse ear model

Summary Dithranol-induced skin irritation and the modulatory effects of different pharmacological agents were studied using the mouse ear model. A single topical application of dithranol caused a dose-dependent skin irritation which resulted in delayed swelling of the mouse ear with two separate peak responses, 1–2 and 6–10 days after application. The irritation was most effectively and persistently inhibited by topical treatment with corticosteroids, the free radical scavenger DL--tocopherol (DLAT) and the serotonin antagonist metergoline. The effect of corticosteroids, however, was slightly diminished during the second peak irritation. The lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA), the dual lipoxygenase and cyclo-oxygenase inhibitor tolfenamic acid and the cyclo-oxygenase inhibitor indomethacin as well as trifluoperazine retained their inhibitory activity. Of these compounds, indomethacin was active only during the first irritation peak, NDGA during both peaks and trifluoperazine principally during the second peak. Retinoic acid did not inhibit the ear swelling. The results confirm and extend the observations that the formation of free radicals is essential for dithranol inflammation. The inflammation can also be suppressed by inhibiting the formation of arachidonic acid or its pro-inflammatory metabolites.     

Anti-inflammatory properties of a prostaglandin antagonist, a corticosteroid and indomethacin in experimental contact dermatitis

The topical effects of N0164 (a phenyl phosphonate derivative which is a partially selective antagonist of prostaglandin E₂), indomethacin and triamcinolone acetonide have been shown to reduce the erythema and ear weight gain from inflammation induced by experimental contact allergic eczema. Oxazolone sensitized Swiss Webster mice were used, ear erythema and ear weights being used as a measure of the anti-inflammatory response to the drugs. N0164 was also shown to have systemic anti-inflammatory activity after intraperitoneal injection.     

咪唑斯汀抑制多形核白细胞白三烯LTB4合成的实验研究

目的：研究咪唑斯汀的抗炎机制。方法：采用皮下植入0．5％花生四烯酸浸泡的海绵做为抗原刺激剂的方法。各组分别在植入前、后2h灌胃给药地塞米松（0．1mg／kg）、咪唑斯汀高剂量（0．3mg／kg）、咪唑斯汀低剂量（0．1mg／kg）、氯雷他定（0．3mg／kg）,结合高效液相的分析方法,定量检测炎症关键产物——白三烯LTB4的生成量。结果：与模型对照组比较,地塞米松组、咪唑斯汀高剂量组有较强的抑制作用（P＜0．01）、咪唑斯汀低剂量组显示出抑制作用（P＜0．05）、而氯雷他定组无抑制作用（P＞0．01）。结论：咪唑斯汀可有效抑制多形核白细胞合成LTB4,咪唑斯汀的抗炎作用机制可能主要通过抑制5-脂氧合酶活性发挥作用。     

Epidermal growth factor stimulates release of arachidonic acid in pig epidermis

Epidermal growth factor (EGF) at physiologic concentrations (0.001-0.1 microgram/ml) stimulated the release of [14C] arachidonic acid [14C-AA] from pig epidermis. Although EGF stimulated the release of AA in the absence of exogenously added calcium to some extent, the addition of calcium (0.3-1.2 mM) significantly potentiated the release of AA stimulated by EGF. Ionophore A23187, which is known to stimulate phospholipase A2 activity by opening the calcium gates, potentiated the EGF-stimulated release of AA. The stimulatory effect of EGF was partially inhibited by the addition of mepacrine (70% inhibition at 10 microM) and by the pretreatment of hydrocortisone (60% inhibition at 1.0 microM). The loss of 14C-labeled phospholipids in pig epidermis was mainly due to the degradation of 14C-labeled phosphatidylcholine. Present results and recent reports by other workers suggest that EGF stimulates phospholipase A2 activity and result in the increased release of AA.     

The stable cyclic adenosine monophosphate analogue,dibutyryl cyclo-adenosine monophosphate (bucladesine), is active in a model of acute skin inflammation

Anti-inflammatory therapeutic options for the topical treatment of skin diseases with inflammatory or allergic contribution are mostly limited to topical glucocorticoids and calcineurin inhibitors. Both compound classes induce adverse effects. Elevation of intracellular cyclic adenosine monophosphate (cAMP) by inhibition of phosphodiesterase 4 was shown to induce potent anti-inflammatory effects, but the safety profile of currently available compounds is not sufficient. A different approach to increase intracellular cAMP is the substitution of chemically stabilized cAMP analogues. Bucladesine is a stabilized cAMP analogue with an excellent safety profile which had been marketed as topical treatment of impaired wound healing. In the current study, a novel water free emulsion containing bucladesine was evaluated for anti-inflammatory effects. In the arachidonic acid induced ear oedema model in mice, single or multiple administration of an emulsion containing 1.5% was capable of significantly reducing the inflammatory oedema. The data indicate that bucladesine represents an interesting treatment option for skin diseases where an anti-inflammatory activity is indicated. Due to the established clinical safety, this agent may bridge the gap between potent agents such as glucocorticoids or calcineurin inhibitors and emollients without active compounds.     

Multiple topical applications of arachidonic acid to mouse ears induce inflammatory and proliferative changes

The response to daily topical applications of arachidonic acid (0.25-4 mg/ear/day) to the ears of outbred CD-1 mice was monitored. The first application produced erythema, extravasation of plasma proteins resulting in an increase in ear weight, and some neutrophil accumulation (detected histologically and quantified by myeloperoxidase content). The second application produced minimal edema but did cause erythema and a greater accumulation of neutrophils. Subsequent daily application caused erythema, neutrophil accumulation, and an increase in ear weight predominantly due to cell proliferation (epidermis and connective tissue). Daily applications of other unsaturated fatty acids did not match the response induced by arachidonic acid. Mast cell deficient mice (W/Wv) exhibited a smaller edema response to the first dose of arachidonic acid compared to either their wild-type controls or CD-1 mice. In addition, W/Wv mice exhibited a smaller ear weight increase and myeloperoxidase accumulation following eight daily doses of arachidonic acid. However, epidermal proliferation was similar in all the strains of mice tested. These data suggest that the edema caused by the first topical application of arachidonic acid is partly mast cell mediated. Mast cells also appear to be involved in the neutrophil infiltration induced by multiple topical applications, but not in the epidermal proliferation.     

Anti-inflammatory effects of eicosapentaenoic acid on experimental skin inflammation models

Anti-inflammatory effects of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) were examined on three models of skin inflammation induced in mice by topical application of an arachidonic acid (AA) solution, ultraviolet-B (UVB) irradiation, and contact sensitization with dinitrofluorobenzen. Ear oedema reactions induced by AA and UVB irradiation were significantly suppressed in mice fed a daily dose of 300 mg/kg EPA for 2 weeks. The contact hypersensitivity reaction was not impaired by EPA. None of the skin reactions was significantly inhibited in mice fed DHA or safflower oil. The results suggest that EPA, but not DHA, has anti-inflammatory effects on AA- and UVB-induced acute inflammation reactions.     

Prostaglandins, leukotrienes, anti-inflammatory substances and their importance in inflammatory reactions of the skin

Prostaglandins appear to play an important role as mediators of inflammation since they fulfill the major criteria. They possess powerful proinflammatory properties; they are present in increased concentrations in a wide range of proinflammatory lesions, and anti-inflammatory drugs inhibit their formation. The role of leukotrienes and other hydroxy fatty acid products is far less clear although their participation in cellular events seems probable. Steroid and nonsteroid anti-inflammatory drugs owe their activity at least in part to inhibition of biosynthesis of prostaglandins, although these two drug classes appear to act at different points in the pathways. It becomes increasingly clear that the oxygenation of arachidonic acid leads to the formation of a multiplicity of pharmacologically active fatty acids of which only a few have so far been identified.     

Anti-bacterial and anti-inflammatory properties of capric acid against Propionibacterium acnes: A comparative study with lauric acid

BackgroundPropionibacterium acnes (P. acnes) is a commensal bacterium which is possibly involved in acne inflammation. The saturated fatty acid, lauric acid (C12:0) has been shown to possess antibacterial and anti-inflammatory properties against P. acnes. Little is known concerning the potential effects of its decanoic counterpart, capric acid (C10:0).ObjectiveTo examine the antibacterial and anti-inflammatory activities of capric acid against P. acnes and to investigate the mechanism of the anti-inflammatory action.MethodsThe antimicrobial activity of fatty acids was detected using the broth dilution method. An evaluation of P. acnes-induced ear edema in mice was conducted to evaluate the in vivo anti-inflammatory effect. To elucidate the in vitro anti-inflammatory effect, human SZ95 sebocytes and monocytic THP-1 cells were treated with P. acnes alone or in the presence of a fatty acid. The mRNA levels and secretion of pro-inflammatory cytokines were measured by qRT-PCR and enzyme immunoassay, respectively. NF-κB activation and MAPK expression were analyzed by ELISA and Western blot, respectively.ResultsLauric acid had stronger antimicrobial activity against P. acnes than capric acid in vitro and in vivo. However, both fatty acids attenuated P. acnes-induced ear swelling in mice along with microabscess and significantly reduced interleukin (IL)-6 and CXCL8 (also known as IL-8) production in P. acnes-stimulated SZ95 sebocytes. P. acnes-induced mRNA levels and secretion of IL-8 and TNF-α in THP-1 cells were suppressed by both fatty acids, which inhibited NF-κB activation and the phosphorylation of MAP kinases.ConclusionOur data demonstrate that both capric acid and lauric acid exert bactericidal and anti-inflammatory activities against P. acnes. The anti-inflammatory effect may partially occur through the inhibition of NF-κB activation and the phosphorylation of MAP kinases.     

咪唑斯汀抗炎活性的动物实验研究

目的:评价抗组胺剂量下咪唑斯汀的抗炎强度,探讨咪唑斯汀抗炎活性的产生机制。方法:给大鼠鼠爪皮下注射花四烯酸0.1mL(1.0g/L)或1%角叉菜胶0.15mL致炎剂,分别构建鼠爪水肿炎性模型,并在注射致炎剂2h前分别给予咪唑斯汀(0.3mg/kg)和西替利嗪(0.3mg/kg)灌胃,注射致炎剂后1、2、3、4h,应用体积测量仪测定给药后鼠爪体积的改变。结果:咪唑汀显著抑制花生四烯酸诱导的鼠爪水肿(P<0.05),对角叉菜胶诱导的鼠爪水肿无抑制作用(P>0.05);西替利嗪(0.3mg/kg)对种致炎剂诱导的鼠爪水肿均无抑制作用(P>0.05)。结论:抗组胺剂量的咪唑斯汀在动物体内具有较高的抗炎活性,咪唑斯汀能通过抑制5-脂氧合酶活性的途径发挥其抗炎活性。     

Enzymatic properties of the 15-lipoxygenase of human cultured keratinocytes

The arachidonic acid 15-lipoxygenase or linoleic acid omega-6 lipoxygenase of human neonatal foreskin cultured keratinocytes converts arachidonic acid to 15-hydroxy-eicosatetraenoic acid and linoleic acid to 13-hydroxy-linoleic acid. A mean of 93% of the 15-lipoxygenase activity in sonicates of cultured keratinocytes was recovered in the 400,000 X g supernatant, attesting to the cytosolic localization of this enzyme. Optimal 15-lipoxygenase activity in the 400,000 X g supernatant was expressed at pH 6.7-7.3 and in the presence of calcium at a concentration of 2 mM or higher. Keratinocyte 15-lipoxygenase metabolized arachidonic acid (Km = 10.6 microM) and linoleic acid (Km = 9.5 microM) with similar efficiency. Nordihydroguaiaretic acid and 5,8,11,14-eicosatetraynoic acid both inhibited the conversion of arachidonic acid to 15-HETE with respective 50% inhibitory concentrations of 2.0 microM and 0.9 microM, while ATP, GTP, and cyclic AMP had no effect on activity at pH 6.8-7.2. The enzymatic properties of human keratinocyte 15-lipoxygenase thus resemble those of PMN leukocyte 15-lipoxygenase and the mediators generated may contribute to the regulation of cutaneous sensation and inflammation.     

Liver X receptor activators display anti-inflammatory activity in irritant and allergic contact dermatitis models: liver-X-receptor-specific inhibition of inflammation and primary cytokine production

Activators of liver X receptors (LXR) stimulate epidermal differentiation and development, but inhibit keratinocyte proliferation. In this study, the anti-inflammatory effects of two oxysterols, 22(R)-hydroxy-cholesterol (22ROH) and 25-hydroxycholesterol (25OH), and a nonsterol activator of LXR, GW3965, were examined utilizing models of irritant and allergic contact dermatitis. Irritant dermatitis was induced by applying phorbol 12-myristate-13-acetate (TPA) to the surface of the ears of CD1 mice, followed by treatment with 22ROH, 25OH, GW3965, or vehicle alone. Whereas TPA treatment alone induced an approximately 2-fold increase in ear weight and thickness, 22ROH, 25OH, or GW3965 markedly suppressed the increase (greater than 50% decrease), and to an extent comparable to that observed with 0.05% clobetasol treatment. Histology also revealed a marked decrease in TPA-induced cutaneous inflammation in oxysterol-treated animals. As topical treatment with cholesterol did not reduce the TPA-induced inflammation, and the nonsterol LXR activator (GW3965) inhibited inflammation, the anti-inflammatory effects of oxysterols cannot be ascribed to a nonspecific sterol effect. In addition, 22ROH did not reduce inflammation in LXRbeta-/- or LXRalphabeta-/- animals, indicating that LXRbeta is required for this anti-inflammatory effect. 22ROH also caused a partial reduction in ear thickness in LXRalpha-/- animals, however (approximately 50% of that observed in wild-type mice), suggesting that this receptor also mediates the anti-inflammatory effects of oxysterols. Both ear thickness and weight increased (approximately 1.5-fold) in the oxazolone-induced allergic dermatitis model, and 22ROH and GW3965 reduced inflammation by approximately 50% and approximately 30%, respectively. Finally, immunohistochemistry demonstrated an inhibition in the production of the pro-inflammatory cytokines interleukin-1alpha and tumor necrosis factor alpha in the oxysterol-treated sites from both TPA- and oxazolone-treated animals. These studies demonstrate that activators of LXR display potent anti-inflammatory activity in both irritant and allergic contact models of dermatitis, requiring the participation of both LXRalpha and LXRbeta. LXR activators could provide a new class of therapeutic agents for the treatment of cutaneous inflammatory disorders.     

Strain-dependent effects of the histamine H₄ receptor antagonist JNJ7777120 in a murine model of acute skin inflammation

The effects of the histamine H(4) receptor antagonist JNJ7777120 were evaluated in a model of acute skin inflammation induced by local application of croton oil. The influence of strain on the effect of JNJ7777120 was investigated in four different mouse strains (CD-1, NMRI, BALB/c and C57BL/6J). In CD-1 mice, JNJ777720 (30-100 mg/kg subcutaneously, s.c.) exerted a dose-dependent inhibition of croton oil-induced ear inflammation and polymorphonuclear leucocyte infiltration, as confirmed by histological evaluation of ear tissues. JNJ7777120 (30-100 mg/kg) did not reduce ear oedema in NMRI, BALB/c or C57BL/6J mice. The positive control, dexamethasone (2 mg/kg s.c.) induced significant anti-inflammatory effects only in CD-1 and NMRI mice. In these strains, also the histamine H(1) -receptor blocker pyrilamine (30 mg/kg s.c.) significantly reduced ear oedema at 2 h after croton oil challenge, being as effective as JNJ7777120 in CD-1 mice. Taken together, these data demonstrate that the H(4) receptor antagonist JNJ7777120 may reduce acute croton oil-induced skin inflammation as effectively as H(1) receptor blockade. However, present experiments evidenced for the first time marked strain-related differences in the JNJ7777120 pharmacological activity, which have to be carefully considered when using this ligand to characterize histamine H(4) receptor functions in murine models and translating preclinical data to clinical human settings.     

Topical peroxisome proliferator activated receptor-alpha activators reduce inflammation in irritant and allergic contact dermatitis models

Activators of peroxisome proliferator activated receptor-alpha, a nuclear hormone receptor that heterodimerizes with retinoid X receptor, stimulate epidermal differentiation and inhibit proliferation. Here we determined the anti-inflammatory effects of peroxisome proliferator activated receptor-alpha agonists in models of irritant and allergic contact dermatitis produced in mouse ears by topical treatment with 12-O-tetradecanoylphorbol-13-acetate and oxazalone, respectively. As expected, 12-O-tetradecanoylphorbol-13-acetate treatment resulted in a marked increase in the thickness and weight of the ears and provoked an inflammatory cell infiltrate in the dermis. Topical treatment with three different peroxisome proliferator activated receptor-alpha agonists, clofibrate, WY 14643, or linoleic acid, 45 min and 4 h after 12-O-tetradecanoylphorbol-13-acetate application, resulted in a marked decrease in ear thickness and weight and a reduction in the number of inflammatory cells in the dermis. The reduction in inflammation by these peroxisome proliferator activated receptor-alpha agonists was of similar magnitude to that seen with a potent topical glucocorticoid, clobetasol. In contrast, stearic acid, a free fatty acid that does not activate peroxisome proliferator activated receptor-alpha, had no effect on the 12-O-tetradecanoylphorbol-13-acetate-induced inflammation. Moreover, clofibrate did not significantly alter ear thickness following 12-O-tetradecanoylphorbol-13-acetate treatment in peroxisome proliferator activated receptor-alpha-/- mice, indicating that the anti-inflammatory effect is mediated by peroxisome proliferator activated receptor-alpha. As tumor necrosis factor-alpha and interleukin-1alpha are major mediators of cutaneous inflammation we next used immunohistochemistry to determine whether the peroxisome proliferator activated receptor-alpha agonists reduce the levels of these cytokines in 12-O-tetradecanoylphorbol-13-acetate-treated skin. 12-O-tetradecanoylphorbol-13-acetate treatment resulted in an increase in tumor necrosis factor and interleukin-1alpha staining in the epidermis that was reduced by clofibrate treatment. Finally, clofibrate treatment also reduced ear thickness and weight in oxazalone-induced allergic dermatitis, a change that was accompanied by a reduction in inflammatory cells in the dermis and a decrease in tumor necrosis factor-alpha and interleukin-1alpha levels in the oxazalone-treated epidermis. These studies demonstrate that topically applied peroxisome proliferator activated receptor-alpha agonists possess receptor mediated, anti-inflammatory activity in both irritant and allergic contact dermatitis animal models. The anti-inflammatory properties of peroxisome proliferator activated receptor-alpha agonists, coupled with their anti-proliferative and pro-differentiating effects, suggest that they could be beneficial for the treatment of a variety of cutaneous diseases.