胎鼠真皮成纤维细胞皮内注射对UV诱导小鼠皮肤光老化的改善作用

目的: 探索体外培养胎鼠真皮成纤维细胞(fibroblasts,FBs)皮内注射对小鼠背部光老化皮肤的改善作用.方法: 分离培养10只第18.5天(E18.5)BALB/c胎鼠皮肤,体外培养FBs两天;用CM-Dil荧光染料进行活细胞标记,以示FBs注射后在体内存活情况.取BALB/c雄性小鼠20只,随机分为:未处理组...     

Effect of intradermal injection of methionine-enkephalin on human skin

Methionine-enkephalin (met-enk) detected in monocytes in psoriatic skin can modulate inflammatory processes and keratinocyte differentiation/proliferation in vitro. The purpose of the present study was to determine the effect of intradermal injection of met-enk on normal human skin and on the development of a delayed type skin hypersensitivity reaction. In 6 healthy volunteers, 50 microl of met-enk (16, 30, and 45 nmol) was injected once in the forearm and the reaction was evaluated clinically and by video-optical recording for 120 min. Compared to vehicle (0.9% saline), met-enk induced a time- and dose-dependent flare reaction, but no significant stimulation of a weal reaction. The flare reaction was maximal after 1 min and disappeared within 45 min. Pre-treatment with the antihistamine cetirizine reduced the flare reaction. Furthermore, the effect of met-enk on lymphocyte/monocyte infiltration and epidermal proliferation in normal skin and on a delayed type skin hypersensitivity reaction was assessed. Met-enk (45 nmol/ 50 microl) was injected at 0, 24 and 48 h. In normal skin, met-enk increased the number of dermal lymphocytes/monocytes (CD3/CD68 positive cells) and the degree of epidermal proliferation (MIBI-Ki67). In a delayed type hypersensitivity reaction induced by tuberculin (PPD), the degree of epidermal proliferation and the number of infiltrating lymphocytes/monocytes were reduced compared to PPD alone. Our study suggests that intradermal injection of met-enk in normal human skin induces an inflammatory reaction that may involve the release of histamine. In contrast, met-enk seems to down-regulate the development of a delayed type skin hypersensitivity reaction. These results may indicate that the direction of the effect of the opioid peptide met-enk on human skin depends on the rate of epidermal proliferation and the activity of immunocompetent cells.     

Changes in sodium-potassium ratio in guinea pig epidermis in n-hexadecane-induced hyperplasia

A transient epidermal hyperplasia was induced in guinea pig epidermis by a single application of n-hexadecane. The epidermal response was analysed by light microscopy and by energy dispersive X-ray microanalysis (EDX). The epidermal hyperplasia reached a maximum between 96 and 192 h after the application. The hyperplastic response was associated with a depressed sodium-potassium ratio (increased potassium, decreased sodium) in the keratinocytes at 96 h, beginning already at 48 h. At 24 h there were no major differences in elemental content, compared the controls. The result of the present study is consistent with the hypothesis that alterations in the functional state of the epidermal keratinocytes are associated with changes in the sodium-potassium ratio in the cells. The absence of major elemental changes at 24 h indicates that the initiation of the hyperplastic response occurred prior to this time point.     

Effect of heparin on histaminase in guinea pig skin

Archives of Dermatological Research -     

Prostaglandin D2 release by guinea pig skin during in vitro anaphylaxis induced by antigen and compound 48/80

The release of prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), and histamine induced by antigen and compound 48/80 was studied using an in vitro model of anaphylaxis in guinea pig skin. Abdominal skin from ovalbumin-sensitized guinea pigs was cut into 0.5-1.0 mm-thick slices which were incubated in Tyrode solution at 37 degrees C with or without either ovalbumin or 48/80. Released PGD2 and PGE2 were measured by radioimmunoassay and gas chromatography-mass spectrometry, respectively. Release of PGD2 was detectable at 2 min after challenge (50 micrograms/ml ovalbumin), reaching a maximum at about 15 min. Histamine release was more rapid, achieving 50% of maximum at about 4 min compared to about 7 min for PGD2. In 11 experiments incubation with ovalbumin (50 micrograms/ml for 10 min) induced a significant 6-fold increase in PGD2 compared to unchallenged controls (399 +/- 53 and 67 +/- 19 ng/g dry weight skin, respectively; mean +/- SEM) and a net 47.2% histamine release. In contrast, a smaller (27%) rise in PGE2 was found. Indomethacin (14 microns) completely suppressed evoked PGD2 and PGE2 synthesis without evident effect on histamine release, suggesting that the release of histamine in this model is not dependent on prostaglandin production. The mast cell degranulating agent compound 48/80 (50 micrograms/ml) released significant amounts of PGD2 (340 +/- 86 ng/g skin compared to 89 +/- 30 ng/g for control skin, n = 5) but had no appreciable effect on PGE2. These results show that guinea pig skin can synthesize significant quantities of PGD2 in anaphylactic reactions. Prostaglandin D2 produced in acute allergic reactions in skin in vivo may contribute to the inflammatory reaction, either directly or in synergism with other mediators.     

Epidermal cell proliferation following an active arthus reaction in the guinea pig

Active Arthus reactions were provoked by injections of 100 micrograms horseradish peroxidase (HRP), 10 micrograms HRP and 100 micrograms bovine serum albumin (BSA) into the skin of sensitized guinea pigs. Labeling indices (LI) of epidermal basal cells were measured 1, 4, 8, 24, 48 and 72 h later by the in vivo 3H-thymidine labeling technique, and compared with those obtained with injections of antigens into the skin of non-sensitized guinea pigs. From 1-8 h after the induction of an active Arthus reaction, the LI of epidermal basal cells of the skin injected with 100 micrograms HRP decreased to a remarkably low value. On the other hand, those obtained with the reaction against 10 micrograms HRP were significantly high. At 24 h after the reaction, LI were as high as those obtained in non-sensitized guinea pigs with control intradermal injections, though the former persisted high until 48 h after the injection. In addition, decreased LI of the epidermal basal cells were observed in the skin 4 h after intradermal injections of immune complexes. It was suggested that DNA synthetic activity of the epidermis increases in a mild active Arthus reaction, while the activity may be suppressed in a severe active Arthus reaction up to 8 h after provocation.     

Human skin dendritic cells can be targeted in situ by intradermal injection of antibodies against lectin receptors

Skin dendritic cells (DC) express C‐type lectin receptors for the recognition of pathogens. Langerhans cells (LC) express the receptor Langerin/CD207, whereas DEC‐205/CD205 is mainly expressed by dermal DC, but can also be detected at low levels on LC. In this study, we tested an ex vivo approach for targeting DC in situ with monoclonal antibodies (mAb) against Langerin and DEC‐205. The targeting mAb was injected intradermally into human skin biopsies or added to the medium during skin explant culture. Corresponding to the expression patterns of these lectin receptors on skin DC, Langerin mAb was detected merely in LC in the epidermis and DEC‐205 mainly in dermal DC in human skin explants, regardless of the application route. Migratory skin DC bound and carried targeting mAb from skin explants according to their lectin receptor expression profiles. In contrast to the very selective transport of Langerin mAb by LC, DEC‐205 mAb was more widely distributed on all CD1a⁺ skin DC subsets but almost absent in CD14⁺ dermal DC. As effective vaccination requires the addition of adjuvant, we co‐administered the toll‐like receptor (TLR)‐3 ligand poly I:C with the mAb. This adjuvant enhanced binding of DEC‐205 mAb to all skin DC subsets, whereas Langerin targeting efficacy remained unchanged. Our findings demonstrate that LC can be preferentially targeted by Langerin mAb. In contrast, DEC‐205 mAb can be bound by all CD1a⁺ skin DC subsets. The efficacy of DEC‐205 mAb targeting strategy can be boosted by addition of poly I:C underlining the potential of this combination for immunotherapeutical interventions.