内皮素拮抗剂对中波紫外线诱导豚鼠色素沉着的观察

目的 探讨内皮素拮抗剂对紫外线诱导豚鼠色素沉着的治疗作用.方法 用中波紫外线(UVB)照射豚鼠皮肤制作色素沉着模型.模型制作成功后,模型动物分为空白对照组(生理氯化钠溶液)、内皮素拮抗剂组及熊果苷组(阳性对照).分别于中波紫外线(UVB)照射前、15 d后及30 d后,用Mexameter(R) MX 18检测豚鼠背部皮肤的黑素指数.连续治疗30 d后比较黑素指数、表皮内黑素细胞数目和黑素含量等指标.结果 UVB照射30 d时,豚鼠背部9块UVB照射区域的黑素指数显著高于照射前(P＜ 0.000 1).外涂1‰内皮素拮抗剂的照射区域30 d后的黑素指数值明显降低,和熊果苷组比较,差异有统计学意义(P＜ 0.000 1).内皮素拮抗组黑素含量指数1明显低于空白对照组(P＜0.05).而3组间黑素含量指数2差异无统计学意义(P＞ 0.05).结论 外涂内皮素拮抗剂对UVB照射诱导豚鼠的色素沉着有一定治疗作用.     

部分植物提取物及药物对中波紫外线诱导的色素沉着斑的抑制作用

目的:检测植物提取物对皮肤色素沉着的抑制作用.方法:以窄谱中波紫外线(NB-UVB)1.5倍的最小红斑量照射,在受试者腹部皮肤建立人工色素沉着模型,分别用3%和5%烟酰胺、1%美白因子、1%羽扇豆素、1%沙棘油、1%和3%橙皮苷、3%维生素C磷酸酯镁、3%甘草酸二铵乳膏涂抹在模型各区域内,以3%氢醌霜为阳性对照,基质为阴性对照,未用药组作空白对照.分别在照射前、照射后1周(即用药前)、用药后第1、2、4、6、8周进行皮肤颜色测量.结果:紫外线照射后7周内,局部皮肤血红蛋白逐渐减少、胶原蛋白合成增加,表皮黑素总量增加.与空白对照区域和阴性对照区域相比,应用1%羽扇豆素、1%沙棘油、3%橙皮苷、3%烟酰胺等制剂的区域,L*值显著增加,高于(P<0.05)或近似于3%氢醌组(P>0.05);局部血红蛋白含量<氢醌组(P<0.01),与基质组相似(P>0.05);且对局部胶原蛋白的合成有轻度促进作用;用SIAscopy<'TM>测定出的局部黑素总量也显著小于空白对照组和阴性对照组(P<0.01),与氢醌组比较差异无统计学意义(P>0.05).结论:羽扇豆素、沙棘油、橙皮苷、烟酰胺、维生素C磷酸酯镁、甘草酸二铵、美白因子使紫外线照射后的色素沉着减轻,作用与氢醌相当,且刺激性小.     

复方熊果苷制剂对中波紫外线照射所致豚鼠皮肤色素沉着的抑制作用

目的研究复方熊果苷制剂对皮肤色素沉着的抑制作用,为其治疗色素沉着性皮肤病提供实验依据。方法选用熊果苷、曲酸、维A酸、维生素E、地塞米松及氢醌6种成分制成不同组合的乳膏,制作棕黄色豚鼠经UVB照射诱导皮肤色素沉着的实验动物模型,采用苏木精一伊红、Schmorl、Imokawa等方法染色,观察外用复方制剂后黑素细胞数量和形态的改变。结果不同组合的复方制剂均使多巴阳性的黑素细胞及含黑素颗粒的细胞数较对照组明显减少（P〈0．05）,其中熊果苷3号、4号与阳性对照组3％氢醌外用差异无统计学意义（P〉0．05）。结论复方熊果苷制剂对UVB诱导的色素沉着具有一定的抑制作用。     

中波高能紫外线诱导豚鼠皮肤色素沉着改变的实验研究

目的 观察中波高能紫外线对皮肤色素沉着的诱导作用及其色素增加的作用机制。方法 以正常棕黄色豚鼠皮肤为实验模型,在其背部脱毛处理后,取4个相邻的区域依次作为对照组和低、中、高剂量中波高能紫外线照射组,分别采用肉眼评估、黑素细胞染色（Imokawa法）以及黑素颗粒染色（Masson-Fontana法）方法,研究中波高能紫外线所致色素沉着作用;应用免疫组化染色法对不同照射剂量组豚鼠皮肤中的一氧化氮合酶（NOS）进行检测;HE染色观察表皮组织学改变。结果 各照射组均出现不同程度的色素沉着,除中、高剂量组色素沉着评分结果差异无统计学意义外,其余各组的色素沉着评分平均黑素数量以及多巴阳性黑素细胞数之间的差异均具有统计学意义（P < 0.05）,且中剂量组结果高于高剂量组。诱导型NOS的表达呈照射剂量依赖式递增,对照组和低、中、高剂量组诱导型NOS含量评分中位数分别为0.50、1.25、1.75、2.00,组间差异具有统计学意义（P < 0.05）。结论 中波高能紫外线可诱导豚鼠皮肤色素增加,且这种效应有一定的剂量依赖性,但并非剂量越高越好。短期内接受中波高能紫外线照射是安全有效的。     

紫外线引起皮肤色素沉着的机制

紫外线引起的皮肤色素沉着包括速发色素沉着和迟发色素沉着。紫外线可通过黑素细胞内的一些分子作用引起皮肤色素沉着 ,但其它细胞也参与色素沉着的发生 ,其中角质形成细胞起非常重要的作用。角质形成细胞可通过旁分泌因子影响黑素细胞黑素的生成。     

白术等对UVB诱导豚鼠皮肤色素沉着的抑制作用

目的 研究中药对皮肤色素沉着的抑制作用,筛选有作用的单味中药,为应用中药治疗色素障碍性皮肤病提供实验依据。方法 选定体外对酪氨酸酶活性有显著抑制作用的中药5味,应用棕黄色豚鼠UVB照射诱导皮肤色素沉着实验动物模型,采用HE、Schmorl、Imokawa等方法染色,观察外用中药后黑素细胞数量和形态的改变。结果 白术、茯苓、山茱萸、猪苓、沙苑蒺藜等中药组多巴阳性黑素细胞数及含黑素颗粒细胞数较对照组明显减少(P<0.01),其中白术、茯苓、山茱萸与阳性对照组3%氢醌外用差异无显著性(P>0.05)。结论 白术、茯苓、山茱萸、猪苓、沙苑蒺藜等中药对UVB诱导的色素沉着具有抑制作用。     

窄谱中波紫外线及其联合中药对H2O2致豚鼠脱色作用的影响

将30只豚鼠随机分为3组。模型组不加治疗;NB-UVB组豚鼠光疗5次/周;NB-UVB联合白驳丸及白癜丸组(联合组),除光疗同NB-UVB组外每日服白驳丸及白癜丸。各组豚鼠每日以H2O2脱色。实验结束后比较靶皮损颜色变化,并取靶皮损用硫酸亚铁LILLIE法染色,观察并计算其中有黑色素毛囊数。结果:模型组与NB-UVB组、联合组相比有明显的脱色,NB-UVB组,联合组靶皮损内有黑素毛囊数均显著少于模型组,但两者之间无显著差异。     

308 nm准分子激光对豚鼠皮肤黑素细胞的影响

目的:研究308 nm准分子激光对皮肤色素沉着的诱导作用,为其治疗白癜风提供科学依据.方法:以正常棕黄色豚鼠皮肤为实验模型,用不同剂量的308 nm准分子激光进行照射,分别采用肉眼评估、黑素细胞染色(Imokawa法)及黑素颗粒染色(Fontana-Masson法)研究该激光的致色素沉着作用;对不同照射剂量组豚鼠皮肤中的一氧化氮合酶(NOS)进行免疫组化染色,间接观察黑素调节因子一氧化氮(NO)的变化情况;苏木精-伊红染色观察表皮组织学改变.结果:各组的色素沉着评分、平均黑素数量以及多巴阳性黑素细胞数之间差异均具有统计学意义(P＜0.05).结论:308 nm准分子激光可诱导豚鼠皮肤色素沉着,且这种效应随着照射剂量的上升而增强.     

中波紫外线的免疫抑制作用研究进展

中波紫外线是到达地球表面的紫外线中引起机体生物学效应的主要光谱,对机体细胞免疫具有抑制作用。其发生机理可能是通过影响表皮郎格罕细胞的功能、形态,从而产生免疫抑制反应。也可能是通过角朊细胞分泌细胞因子如α-肿瘤坏死因子、白介素-1、白介素-10、粒细胞-单核细胞集落刺激因子等间接发挥作用。位于皮肤角质层作为光受体的尿刊酸及皮肤靶细胞DNA的直接损伤亦与中波紫外线诱发的免疫抑制作用有关。     

Differential analysis of experimental hypermelanosis induced by UVB,PUVA, and allergic contact dermatitis using a brownish guinea pig model

Summary In moderately colored guinea-pig skin, UVB, PUVA, and allergic contact dermatitis were shown to induce hyperpigmentation that resembled the pigmentary changes observed in mongoloid human skin. Using this model, we examined the effects of chemical agents, including tyrosinase inhibitors and sunscreen agents, on the color changes induced by UV irradiation. The daily exposure of brownish guinea-pig skin to UVB irradiation at a variety of energies for 3 successive days induced clearly visible black pigmentation on the irradiated rectangular areas of the flank within a few days of irradiation, the maximum being reached about 1 week after irradiation, i.e., similar to the changes that occur in pigmented human skin. Split epidermal sheets prepared from untreated pigmented guinea pigs exhibited 200–400 melanocytes/mm²; 1 week after UV irradiation, the applied areas show an increased number of strongly dopa-positive melanocytes with stout dendrites (800–1,000 cells/mm²). UVA irradiation following an intraperitoneal injection of 8-methoxypsoralen (8-MOP) also produced black pigmentation 1 week after irradiation, and this was paralleled by a marked increase in the number of dopa-positive melanocytes in dopa-reacted split epidermal sheets. Allergic contact dermatitis produced by the application of 1-phenylazo-2-naphtol induced hyperpigmentation after an interval of about 14 days in 10 of the 21 allergy-acquiring animals examined. This induced pigmentation was accompanied by an increase in the number of dopa-positive melanocytes as compared to the number seen in controls. In contrast, allergic contact dermatitis produced by the application of dinitrochlorobenzene failed to induce such a high ratio of postpigmentation, with only 3 of the 21 allergy-acquiring animals showing hyperpigmentation and 5 showing depigmentation; in the latter, there was a slight decrease in the number of dopa-positive melanocytes. To study the preventive effect of tyrosine inhibitors on UVB-induced pigmentation, daily topical applications of these compounds were performed after three daily UVB irradiations. Treatment with 10% hydroquinone for 10 days interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to the number found in UVB-irradiated, untreated control skin.     

烟酰胺干预UVB诱导豚鼠皮肤色素沉着的作用

目的探讨烟酰胺对中波紫外线（UYB）致豚鼠皮肤色素沉着的抑制作用。方法以亚红斑剂量UYB照射豚鼠背部10天建立皮肤无急性损伤色素沉着动物模型后，外涂基质和2．5％、5％、10％的烟酰胺4周，在此期间观察肤色改变和测定皮肤L值。涂药结束后取材，进行Masson—Fontana、冰冻切片Dopa染色和黑素细胞超微结构观察，观察黑素细胞数量、形态和功能的改变。结果涂抹5％烟酰胺4周后，豚鼠皮肤变白，L值显著下降，多巴阳性黑素细胞数及黑素含量指数较对照组明显减少（P〈0．05）。结论5％烟酰胺对UVB诱导的色素沉着有明显的抑制，它主要是通过抑制黑素细胞的增殖和黑素细胞内黑索小体的合成而发挥作用。     

The guinea pig as a model for predicting photoallergic contact dermatitis

This report describes modifications in the techniques used for both the induction and elicitation of photoallergic contact dermatitis (PACD) in the guinea pig. These changes have improved the reliability of this animal as the model of choice for screening chemicals or products for (heir tendency to produce PACD.
The induction period consists of 15 exposures of the test substance to shoulder skin that has been abraded with a nylon brush rotating at 13,000 rpm. One hour later, the KM site is irradiated with broadband UVA from a source having some irradiance below 320 nm (UVA/b). The animals receive 450 J/cm² of UVA during the three-week induction period. The elicitation (challenge) test is repeated fur two consecutive days. Each day, the test material, if a liquid, is applied to two sties even 30 lo 60 min for 6 h; then one of the sites receives 20 J/cm² of UVA.
These photo-induction and photo-elicitation procedures have demonstrated that low-level concentrations (0.25% range) of 6-melhyl coumarin or musk ambrette will both induce and elicit PACD in the guinea pig. This report adds more evidence that the induction of PACD in the guinea pig is dependent on broadband UVA.     

A new animal model for contact dermatitis: the hairless guinea pig.

Allergic and irritant contact reactions were evaluated in the recently identified hairless guinea pig, Crl:IAF(HA)BR, a mutant from the Hartley strain. The cutaneous changes were observed macro- and microscopically. The irritant contact dermatitis was induced by croton oil, 2,4-dinitrochlorobenzene (DNCB), or anthralin. Both hairless and hairy guinea pigs developed similar reactions to these chemicals. The density of the epidermal Langerhans cells (LC) of hairless guinea pigs was significantly higher than that in the hairy strain. Allergic contact sensitization was easily induced with DNCB. Photoallergic contact sensitization was also induced with tetrachlorosalicylanilide (TCSA) but not with tribromosalicylanilide (TBS). However, by administration of cyclophosphamide before sensitization, positive photocontact responses were seen with TBS. These results indicate that hairless guinea pigs can be used as animal models for investigation of immunologic and nonimmunologic contact reactions.     

Dose-response studies of contact allergens using 3 guinea pig models

A multi-dose-response induction protocol for the guinea pig maximization test (GPMT), including a statistical computer program, has earlier been developed to improve the power of predictive tests for identification of contact allergens. This dose-response protocol, with 2 modifications (i.e., increased number of animals in each group and increased number of challenge concentrations) was evaluated in the GPMT, the cumulative contact enhancement test (CCET) and the Freund's complete adjuvant test (FCAT), using potassium dichromate and hydroxycitronellal as model contact allergens. Application of the dose-response protocol on the CCET and the FCAT resulted in either monotone or non-monotone curves with significant dose-response. However, application of the dose-response protocol on the GPMT gave curves with no significant dose-response. The protocol makes it possible to obtain an EC50 value, thus improving the possibility of ranking contact allergens, which is of substantial use for risk assessments. The dose-response protocol could benefit from a few adjustments: a wider span in the induction doses; change to simultaneous increase in intradermal and topical induction doses to obtain a proper dose-response for the GPMT; the addition of further challenge concentrations. In addition the computer program should allow calculation of threshold concentration for sensitization and EC50 value for a non-monotone curve.     

深部克柔念珠菌感染豚鼠模型的建立及致病性初步研究

目的建立深部克柔念珠菌感染的豚鼠模型,并对其进行致病性研究。方法采用皮下注射曲安奈德和腹腔注射环磷酰胺诱导豚鼠进入免疫抑制状态后,静脉注射克柔念珠菌悬液,使豚鼠发生深部克柔念珠菌感染;与免疫正常组(对照组)豚鼠比较,观察两组死亡情况和脏器的组织载菌量,并进行统计学分析。结果免疫抑制组(实验组)豚鼠的死亡从感染后1d开始,3～4d达到高峰,至第6天止,其死亡率是正常组的10倍(P<0.01);各脏器的组织载菌量明显高于对照组(P<0.05);在检查的4种脏器中,最为易感的是肾脏,最不易感的是肝脏,各脏器间易感的差异有显著性(P<0.01)。结论本实验能有效诱导豚鼠的免疫抑制状态,明显增加豚鼠体内发生深部克柔念珠菌感染的概率;豚鼠的死亡率和组织载菌量是客观反映豚鼠体内真菌感染情况的敏感观察指标。用上述方法成功建立的深部克柔念珠菌感染豚鼠模型可用于后续抗真菌药体内抗真菌活性的研究。     

Zinc effects on nickel dermatitis in the guinea pig

Prevention of NiSO₄ induced allergic, contact dermatitis (ACD) using ZnSO_{4 in} drinking water was studied in a guinca pig model Without ZnSO₄ intervention, nickel (Ni)-exposure resulted in significantly higher (p<0.05) stimulation indices (SIs) as compared to non-exposed controls, using NiSO₄ as an allergen in the lymphocyte transformation test (LTT). Oral intake of ZnSO₄ at both 250 μg/ml double-distilled deionized water (DDD) and 500 μg/ml DDD resulted in lower SIs than those of control guinea pigs drinking only DDD: the 250 μg ZnSO₄/ml group had significantly lower Sis than (p= 0.025) than controls. There was no significant correlation between intradermal test responses and the SI values of individual guinea pigs exposed to NiSo₄ Mean Zinc (Zn) concentrations in skin and in whole blood were not statistically different between the NiSO₄ exposed control and Zn supplemented groups, nor between Ni-sensitive and non-sensitive animals within groups. The rôle of Zn homeostasis role of the Langerhans cell, effect of Zn supplementation on Ni ACD in other species, and possible blocking effects of other metals should be investigated in future studies.     

Topical application of artesunate on guinea pig allergic contact dermatitis

Artesunate is derived from the Chinese medicinal herb qinghao. Many animal studies suggest that systemic artesunate has immunoregulatory activity. We investigated the effect of topical artesunate on contact sensitivity in guinea pigs sensitized with DNCB. Female hairless guinea pigs were used and the contact reaction graded by visual (5 point) score and erythema measured with a color analyzer. Topical artesunate inhibited the elicitation reaction of contact hypersensitivity when given at the 1st and 12th h after challenge ( p < 0.05), but showed no effect when given from day 3 to day I before challenge ( p > 0.05). Artesunate had no effect on toxic (irritant) contact dermatitis from 20% croton oil ( p > 0.05). The results indicate that topical application of artesunate may offer a novel treatment of allergic contact dermatitis and other cutaneous immune-mediated disorders.     

Cutting oil dermatitis on guinea pig skin

The effect of repeated exposure of cutting oil on 8 guinea pigs' skin was evaluated by visual scoring for erythema and skin water vapour loss (SVL) measurement over a 6-week period. The visual scores (measuring severity of erythema) and SVL values were significantly higher on skin treated with cutting oils (positive control) compared to untreated skin (negative control) throughout the study period. The scores and SVL values returned to near-baseline values when cutting oil application was stopped. In addition, the effect of 2 "after-work" emollient creams on 8 guinea pigs' skin repeatedly treated with a cutting oil was assessed by similar methods. The visual scores and SVL values of guinea pig skin that was repeatedly treated with the cutting oil and moisturized with "after-work" emollient creams, were significantly higher than negative and positive control guinea pig skin. It appeared that the 2 "after-work" emollient creams do not alleviate the irritant effect of the cutting oil on guinea pig skin. They appeared to aggravate the irritant effect of the cutting oil.     

Cutting oil dermatitis on guinea pig skin

We assessed the effect of repeated application of cutting oil on 9 guinea pigs' skin by visual scoring and skin water vapour loss measurement. The visual scores (severity score) were significantly higher on skin treated with cutting oil (positive control) compared to untreated skin (negative control). The corresponding mean SVL values were also significantly higher. We also assessed the effect of 2 barrier creams on the 9 guinea pigs' skin treated with cutting oil. The visual scores on skin treated with either barrier cream were significantly higher than positive control skin. The corresponding mean SVL values on skin treated with either barrier cream were also higher (not statistically significant). It appeared that the 2 barrier creams did not confer protection against the irritant effect of the cutting oil. On the contrary, barrier creams appeared to exacerbate the irritant effect of cutting oil.