Skin care efficacy study of recombinant humanized collagen based on in vitro level

Studying the skin care efficacy of recombinant humanized collagen based on in vitro level.The stability of the recombinant humanized collagen was first analyzed by treating at different temperatures,then its skincare efficacy based on in vitro level was evaluated by detecting the inhibition rate of elastase,the inhibition rate of collagenase,the protein content of type I collagen in human fibroblasts,the inhibition of reactive oxygen species(ROS)with human keratinocytes,and the effects of the recombinant humanized collagen on the expression of hyaluronic acid(HA),filaggrin(FLG)and transglutaminase 1(TGM1)in keratinocytes.The results showed that recombinant humanized collagen was able to maintain stability at temperatures below 70℃.With regard to its skincare efficacy,recombinant humanized collagen could inhibit elastase and collagenase activities and promote the increase of type I collagen content in human fibroblasts.It also showed good inhibition of ROS in keratinocytes in vitro and could increase the expression of HA,FLG,and TGM1 in keratinocytes.In short,the recombinant humanized collagen exhibited a favourable skin care effect in vitro level.This study proved that it has potential firming,anti-wrinkle,moisturizing,and repairing efficacy,and is a valuable cosmetic raw material.

Autocrine IL-8 Contributes to Propionibacterium Acnes-induced Proliferation and Differentiation of HaCaT Cells via AKT/FOXO1/Autophagy

Objective Proprionibacterium acnes(P.acnes)-induced inflammatory responses,proliferation and differentiation of keratinocytes contribute to the progression of acne vulgaris(AV).P.acnes was found to enhance the production of interleukin-8(IL-8)by keratinocytes.This study aimed to investigate the role of IL-8 in P.acnes-induced proliferation and differentiation of keratinocytes and the underlying mechanism.Methods The P.acnes-stimulated HaCaT cell(a human keratinocyte cell line)model was established.Western blotting and immunofluorescence were performed to detect the expression of the IL-8 receptors C-X-C motif chemokine receptor 1(CXCR1)and C-X-C motif chemokine receptor 2(CXCR2)on HaCaT cells.Cell counting kit-8(CCK-8)assay,5-ethynyl-20-deoxyuridine(EdU)assay and Western blotting were performed to examine the effects of IL-8/CXCR2 axis on the proliferation and differentiation of HaCaT cells treated with P.acnes,the IL-8 neutralizing antibody,the CXCR2 antagonist(SB225002),or the CXCR1/CXCR2 antagonist(G31P).Western blotting,nuclear and cytoplasmic separation,CCK-8 assay,and EdU assay were employed to determine the downstream pathway of CXCR2 after P.acnes-stimulated HaCaT cells were treated with the CXCR2 antagonist,the protein kinase B(AKT)antagonist(AZD5363),or the constitutively active forkhead box O1(FOXO1)mutant.Finally,autophagy markers were measured in HaCaT cells following the transfection of the FOXO1 mutant or treatment with the autophagy inhibitor 3-methyladenine(3-MA).Results The expression levels of CXCR1 and CXCR2 were significantly increased on the membrane of HaCaT cells following P.acnes stimulation.The IL-8/CXCR2 axis predominantly promoted the proliferation and differentiation of P.acnes-induced HaCaT cells by activating AKT/FOXO1/autophagy signaling.In brief,IL-8 bound to its receptor CXCR2 on the membrane of keratinocytes to activate the AKT/FOXO1 axis.Subsequently,phosphorylated FOXO1 facilitated autophagy to promote the proliferation and differentiation of P.acnes-induced keratinocytes.Conclusion This study demonstrated the novel autocrine effect of IL-8 on the proliferation and differentiation of P.acnes-induced keratinocytes,suggesting a potential therapeutic target for AV.

Optimization of LPS-Induced Inflammation Model and Its Feasibility as a Fast Screening Model for Cosmetics

Objectives: The existing inflammatory models are concentrated in relatively complex medical fields, and most of them use a single type of cell, and the induction conditions are not uniform, so the current LPS-induced inflammation model is less conducive to the study of skin inflammation. The aim of this research is to enhance the existing LPS-induced inflammation model and establish a skin inflammation model that is suitable for the swift screening of anti-inflammatory agents in the cosmetics industry. Methods: LPS was used to induce inflammatory responses in KC and THP-1 cells. Enzyme-linked immunosorbent assay (ELISA) was employed to assess the levels of IL-1α, IL-8, and TNF-α in the two cell types, while the DCFH-DA probe was utilized to label the levels of reactive oxygen species (ROS) in both cell types. Results: In KC cells, 10 μg/mL of LPS induced a significant upregulation of IL-8 but did not result in elevated expression of IL-1α. However, at 100 μg/mL of LPS, both IL-8 and IL-1α were highly expressed in KC cells. LPS concentrations ranging from 0.01 to 100 μg/mL failed to stimulate TNF-α production in KC cells but induced a gradient increase in ROS levels. In THP-1 cells, LPS concentrations from 0.01 to 100 μg/mL did not induce IL-1α production but significantly elevated IL-8 and led to a gradient increase in TNF-α and ROS. After treatment with 100 μg/mL of LPS, the cosmetic ingredient Rucika KGM mitigated the elevated levels of IL-1α, IL-8, and ROS in LPS-induced KC cells and IL-8 and ROS in THP-1 cells. Conclusion: This study has successfully developed an application-oriented model suitable for investigating skin inflammation, enabling the rapid and comprehensive screening of cosmetic ingredients with anti-inflammatory activity. .

Quantification of In Vivo Epidermal Keratinocyte Architecture Associated with the Signs of Skin Aging and the Skin Benefit Evaluation by Application of Galactomyces Ferment Filtrate (Pitera)-Containing Skin Care Product

Background: Aged skin exhibits visual alterations such as wrinkles, rough texture, pore dilation, and dull skin tone, as well as physiological aging, namely, decreased hydration and increased transepidermal water loss (TEWL). Recent advances in coherence tomography have also revealed that skin aging affects in vivo epidermal keratinocyte architecture. However, the interconnectivity between spatial architectural aging and visual/physiological aging parameters remains largely unknown. Purpose: To elucidate whether the tomographic keratinocyte architectural aging is correlated with visual and physiological skin aging parameters and to quantitatively evaluate the improvements of the architectural, visual, and physiological aging parameters by the daily treatment of the skin care formula containing Galactomyces Ferment Filtrate (GFF, 8X PiteraTM). Method: We measured the in vivo keratinocyte cellular architecture with two-photon stereoscopic tomography obtaining by-layer epidermal section images in 78 Asian females of various ages. Visual aging parameters were analyzed using a portable image capture system. Hydration and TEWL were also assessed. The anti-aging effects of GFF-containing skin moisturizer (SK-II LXP CreamTM) were also examined in two studies after twice-daily application for 2 (N = 35) and 4 (N = 32) weeks. Results: As for the keratinocyte cellular architecture, skin aging was significantly associated with decreased cell density and increased cell uniformity. These architectural aging parameters were significantly correlated with visual and physiological aging parameters, namely, rough texture, wrinkles, pore dilation, dull skin tone, dehydration, and increased TEWL. The strong interconnectivity allowed us to develop formulae to estimate the keratinocyte architecture from visual aging parameters. Moreover, twice-daily application of SK-II significantly improved the keratinocyte architecture associated with multiple skin aging visual and physiological parameters. Conclusion: Skin aging is a process involving mutual interconnections among epidermal keratinocyte cellular architecture, visual, and physiological parameters. The GFF-containing moisturizer SK-II effectively improves spatial architecture of keratinocytes in epidermis and these evaluated skin aging parameters in a new trajectory over the course of treatment. .

IL-36β Promotes Inflammatory Activity and Inhibits Differentiation of Keratinocytes In Vitro

Objective Psoriasis is an immune-mediated inflammatory disease.Despite advances in the study of its pathogenesis,the exact development mechanism of psoriasis remains to be fully elucidated.Hyperproliferative epidermis plays a crucial role in psoriasis.This study aimed to investigate the effects of interleukin-36β(IL-36β)on keratinocyte dysfunction in vitro.Methods Human keratinocyte cell lines,HaCaT cells,were treated with 0(control),50 or 100 ng/ml IL-36βrespectively for 24 h.Cell viability was determined with a cell counting kit-8 assay.Flow cytometry was used to assess the effects of IL-36βon apoptosis and cell cycle distribution.Expressions of the differentiation markers,such as keratin 10 and involucrin,were evaluated by quantitative real-time polymerase chain reaction(RT-qPCR).Expressions of the inflammatory cytokines,IL-1βand IL-6 were tested by ELISA.Results CCK8 assay showed the survival rate had no significant difference between the control and treated group(P>0.05).Flow cytometry analysis showed cell cycle arrest at S phase in the IL-36β-treated groups compared with the control group(P<0.05).RT-qPCR verified the decreased mRNA expressions of keratin 10 and involucrin in the IL-36β-treated groups compared with the negative control(P<0.01).ELISA showed 100 ng/ml IL-36βenhanced levels of IL-1βand IL-6 in culture supernatants of HaCaT cells compared with the negative control(P<0.05).Conclusion Taken together,these findings suggest that IL-36βcould induce cell cycle arrest at S phase,inhibit keratin 10 and involucrin expressions and promote inflammatory activity in HaCaT cell lines.

Keratinocyte growth factor gene therapy ameliorates ulcerative colitis in rats

AIM:To investigate the effect of keratinocyte growth factor(KGF) gene therapy in acetic acid-induced ulcerative colitis in rat model.METHODS:The colitis of Sprague-Dawley rats was induced by intrarectal infusion of 1 mL 5%(v/v) acetic acid.Twenty-four hours after exposed to acetic acid,rats were divided into three experimental groups:control group,attenuated Salmonella typhimurium Ty21a strain(SP) group and SP strain carrying human KGF gene(SPK) group,and they were separately administered orally with 10% NaHCO3,SP or SPK.Animals were sacrificed and colonic tissues were harvested respectively on day 3,5,7 and 10 after administration.Weights of rats,colonic weight/length ratio and stool score were evaluated.Histological changes of colonic tissues were examined by hematoxylin and eosin(HE) staining method.The expression of KGF,KGF receptor(KGFR) and TNF-α were measured either by enzyme-linked immunosorbent assay or Western blotting.Immunohistochemistry was used to detect the cellular localization of KGFR and Ki67.In addition,superoxide dismutase(SOD) activity and malondialdehyde(MDA) contents in the homogenate were measured.RESULTS:Body weight and colonic weight/length ratio were declined in SPK group compared with SP and control groups(body weight:272.78 ± 17.92 g vs 243.72 ± 14.02 g and 240.68 ± 12.63 g,P < 0.01;colonic weight/length ratio:115.76 ± 7.47 vs 150.32 ± 5.99 and 153.67 ± 5.50 mg/cm,P < 0.01).Moreover,pathological changes of damaged colon were improved in SPK group as well.After administration of SPK strain,KGF expression increased markedly from the 3rd d,and remained at a high level till the 10th d.Furthermore,KGFR expression and Ki67 expression elevated,whereas TNF-α expression was inhibited in SPK group.In the group administered with SPK,SOD activity increased significantly(d 5:26.18 ± 5.84 vs 18.12 ± 3.30 and 18.79 ± 4.74 U/mg,P < 0.01;d 7:35.48 ± 3.35 vs 22.57 ± 3.44 and 21.69 ± 3.94 U/mg,P < 0.01;d 10:46.10 ± 6.23 vs 25.35 ± 4.76 and 27.82 ± 6.42 U/mg,P < 0.01) and MDA contents decreased accordingly(d 7:7.40 ± 0.88 vs 9.81 ± 1.21 and 10.45 ± 1.40 nmol/mg,P < 0.01;d 10:4.36 ± 0.62 vs 8.41 ± 0.92 and 8.71 ± 1.27 nmol/mg,P < 0.01),compared with SP and control groups.CONCLUSION:KGF gene therapy mediated by attenuated Salmonella ameliorates ulcerative colitis induced by acetic acids,and it may be a safe and effective treatment for ulcerative colitis.

Comparison of the Histological Morphology between Normal Skin and Scar Tissue

Skin wound healing is a complex event, and interrupted wound healing process could lead to scar formation. The aim of this study was to examine the morphological changes of scar tissue. Pathological staining（HE staining, Masson＇s trichrome staining, methenamine silver staining） was used to evaluate the morphological changes of regenerating epidermis in normal skin and scar tissue, and immunofluorescence staining to detect the expression of collagen Ⅳ, a component of basement membrane（BM）, and the expression of integrinβ4, a receptor for BM laminins. Additionally, the expression of CK14, CK5, and CK10 was measured to evaluate the proliferation and differentiation of keratinocytes in normal skin and scar tissue. The results showed that the structure of the skin was histologically changed in scar tissue. Collagen Ⅳ, expressed under the epidermis of normal skin, was reduced distinctly in scar tissue. Integrinβ4, expressed in the basal layer of normal skin, was found absent in the basal layer of scar tissue. Additionally, it was found that keratinocytes in scarring epidermis were more proliferative than in normal skin. These results indicate that during the skin wound healing, altered formation of BM may affect the proliferation of keratinocytes, reepithelial and tissue remodeling, and then result in scar formation. Thus, remodeling BM structure during wound repair may be beneficial for improving healing in cutaneous wounds during clinical practice.

Related gene expressions in anti-keratinocyte aging induced by Ganoderma lucidum polysaccharides

Objective:To examine the level of expression of anti skin aging gene of Ganoderma lucidum polysacchayides and clarify its mechanism with anti aging of this ancient Chinese medicine.Methods:HacaT cell of keratinocytes lines were cultured and treated with the polysaccharides.The total RNA was extracted with Trizol reagent and cDNA was synthesized by reverse thanscription.The obtained cDNAs were then fluorescently labeled with cy3 and cy5 respectively and hybridized with gene expressing pedigree cDNA chip.The images were scanned and analyzed with special software.The scan data were analyzed with software and checked by real time PCR.Results:Among total 18 346 human genes,the expression of 103 ones was up-regulated and 378 ones down-regulated.It was demonstrated evidently that Ganoderma lucidum polysaccharides affected the expression of genes of anti skin aging.Two ways are anastomotic.Conclusion:it is concluded by analysis of function of these up-regulation and down-regulation genes that Ganoderma lucidum polysaccharides may play an important role in boosting cell growth and against skin aging.It shows that the results of gene array reliable by real time PCR.

Keratinocyte growth factor-2 and autologous serum potentiate the regenerative effect of mesenchymal stem cells in cornea damage in rats

AIM:To investigate the healing process after severe corneal epithelial damage in rats treated with mesenchymal stem cells(MSCs)cultured with or without keratinocyte growth factor(KGF-2)and autologous serum(AS)on amniotic membrane(AM).Many patients are blind and devastated by severe ocular surface diseases due to limbal stem cell deficiency.Bone marrow-derived MSCs are potential sources for cellbased tissue engineering to repair or replace the corneal tissue,having the potential to differentiate to epithelial cells.METHODS:The study included 5 groups each including 10 female'Sprague Dawley'rats in addition to20 male rats used as bone marrow donors.Group I rats received AM+MSCs,Group II rats AM+MSCs cultured with KGF-2,Group III rats AM+MSCs cultured with KGF-2+AS,Group IV rats only AM and Group V rats,none.AS was derived from blood drawn from male rats and bone marrow was obtained from the femur and tibia bones of the same animals.Therapeutic effect was evaluated with clinical,histopathological and immunohistochemical assessment.MSC engraftment was demonstrated via detection of donor genotype(Y+)in the recipient tissue(X)with polymerase chain reaction.RESULTS:Corneal healing was significantly better in Groups I-III rats treated with MSC transplantation compared to Group IV and Group V rats with supportive treatment only.The best results were obtained in Group III rats with 90%transparency,70%lack of neovascularization,and 100%epithelium damage limited to less than 1/4 of cornea.CONCLUSION:We suggest that culture of MSCs with KGF-2 and AS on AM is effective in corneal repair in case of irreversible damage to limbal stem cells.

Cultured keratinocyte grafting on various biologic matrices

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Photoprotective Effects of Hydroxychloroqine and TCMs on Human Keratinocytes Damaged from Ultraviolet Irradiation

Objective: To investigate damage effects of ultraviolet irradiation on eternal keratinocyte-HaCaT cells and to evaluate photo-protective efficiency of hydroxychloroqine and Traditional Chinese Medicines(epigallocatechingallate[EGCG], baikal skullcap root and szechwan lovge rhizome) on HaCaT cells damaged by middle wave ultraviolet(UVB) irradiation. Methods: Subconfluent HaCaT cells were sham or UVB irradiated and treated with above TCM agents. The damage degree of HaCaT cells was observed by a light microscop. Cell growth was recorded by cell count and cellular activity was detected by MTT method. The secretion amount of IL-6 and TNF-α was measured by ELISA. Results: The irradiation damage of HaCaT cells was depended on the irradiated dosages and cellular activity was reduced by 36%-80%, with a maximum decrease over 90% after 72 h. The intervention of the above drugs may increase the cellular activity by 10%-72%. The photo-protective efficiency was more apparent in EGCG (from 1.19±0.07 to 1.28±0.06, P<0.01) than that in hydroxychloroqine (from 0.43±0.04 to 0.96±0.04, P<0.05). The other two tested drugs also showed photo-protective effect(from 0.44±0.07 to 1.21±0.02, P<0.05). As to cytokine secretion, EGCG could decline the secretion amount of IL-6 and TNF-α apparently. Hydroxychloroqine and baikal skullcap root baikal skullcap root could only reduce the secretion of IL-6. The secretion of IL-6 and TNF-α could not be inhibited by szechwan lovge rhizome. Conclusion: The injury effect of UVB irradiation on cultured keratinocytes is dose-dependent and the tested drugs have photo-protective potency. Inhibition of cytokine secretion may be one of the mechanisms related to reducing the damage effect of UVB irradiation.

Intestinal hormones and growth factors:Effects on the small intestine

There are various hormones and growth factors which may modify the intestinal absorption of nutrients, and which might thereby be useful in a therapeutic setting, such as in persons with short bowel syndrome. In part I, we focus first on insulin-like growth factors, epidermal and transferring growth factors, thyroid hormones and glucocorticosteroids. Part Ⅱ will detail the effects of glucagon-like peptide （GLP）-2 on intestinal absorption and adaptation, and the potential for an additive effect of GLP2 plus steroids.

A Comparative Study on the Enhancement Efficacy of Specific and Non-specific Iron Chelators for Protoporphyrin Ⅸ Production and Photosensitization in HaCat Cells

The iron chelators can be utilized in target cells to improve 5-aminolaevulinic acid （ALA）-based photodynamic therapy （PDT）. The purpose of this study is to compare the effect of two kinds of iron chelators, desferrioxamine （DFO） and ethylenediaminetetraacetic acid （EDTA） on the enhancement of ALA-PDT. HaCat cells were cultured in medium containing 2.0 mmol/L of ALA and 0.5 mmol/L of DFO or EDTA. After 3-h incubation in the dark, the concentration of cellular pro-toporphyrin Ⅸ （PpⅨ） was detected by high performance liquid chromatography （HPLC）, and the fluorescence of PpⅨ was observed at 630 nm emission under confocal laser scanning microscope. For PDT, HaCat cells were irradiated using 632.8 nm laser, and the fractions of apoptotic and necrotic cells were flow cytometrically assayed. Related differences in morphology and ultrastructure of Ha-Cat cells were observed using optical microscope or transmission electron microscope. Compared to incubation with ALA alone, the addition of DFO or EDTA increased the concentration of cellular PpⅨ and the fluorescent density of PpⅨ, and also increased cell death ratio after PDT. PDT using ALA plus DFO produced the highest cellular PpⅨ level, greatest cell death ratio and most severe structural damage to the cells. It was concluded that both DFO and EDTA could enhance ALA-based PpⅨ production and PDT. Compared to the non-specific iron chelator of EDTA, the specific chelator, DFO, showed more potential for the enhancement.

Issues within Keratinocyte Growth Factor （KGF） research

As the seventh member of Fibroblast Growth Factor （FGF） family, Keratinocyte Growth Factor （KGF or FGF-7） is observed tp mediate epithelial cell proliferation and differentiation in a variety of tissues. In this article, such following issues within KGF research were reviewed, as （1） KGF functioning pathways： experimental results demonstrated the paracrine pathway of KGF played main role in mesen- chymal-epithelial interactions whereas KGF itself was under the control of a feedback regulation, autocrine provided KGF alternative functioning way particularly in tumourogenesis; （2） KGF in apoptosis： a few of investigations recently illustrated KGF mediated cell survival was based on its mitogenic function via stimulating cell growth, moreover KGF could inhibit the ROS-induced apoptosis through Nrf-2 pathway; （3） KGF during tumourogenesis： high expression of KGF enhanced progression, motility and invasiveness of tumor cells and various cancers, in company with paracrine loop replaced by autocrine loop, meanwhile KGF clearly played the early signal in the progression of breast cancer; （4） Medical application and administration of KGF： KGF had been successfully used in several preclinical models of radiation and chemotherapy-induced mucositis, and developed into commercial medicine （i.e. Palifermin ）, however more effective delivery systems are still under trial.

Cell-free derivatives from mesenchymal stem cells are effective in wound therapy

AIM:To compare the efficacy of cell-free derivatives from Bone marrow derived human mesenchymal stem cells(hMSCs) in wound therapy.METHODS:hMSCs have been shown to play an important role in wound therapy.The present study sought to compare efficacy of hMSCs and cell-free derivatives of hMSCs,which may be clinically more relevant as they are easier to prepare,formulate and transport.hMSCs were isolated from human bone marrow and cultured.Multi lineage differentiation of hMSCs was performed to confirm their identity.The ability of hMSCs to migrate was evaluated using in vitro and in vivo migration assays.Cell lysates and conditioned medium concentrate was prepared from hMSCs(see Methods for details).Wounds were induced in mice and wound areas were measure before and after cell and cell-free derivative treatment.RNA and proteins were extracted from the skin and cytokine levels were measured.RESULTS:Co-culture of hMSCs with keratinocytes resulted in increased expression of CXCL-12(SDF1) and ENA78(CXCL-5) in the conditioned media indicating that the hMSCs can respond to signals from keratinocytes.Accelerated wound closure was observed when hMSCs were injected near the site of excisional wounds in athymic as well as NOD/SCID mice.Interestingly,cell-free lysates prepared from hMSCs were also effective in inducing accelerated wound closure and increased expression of SDF1 and CXCL-5 at the wound bed.Additionally,concentrated media from hMSCs as well as an emulsion containing lysates prepared from hMSCs was also found to be more effective in rapid re-epithelialization than fibroblasts or vehicle-alone control.Use of cell-free derivatives may help replace expensive wound care approaches including use of growth factors,epidermal/dermal substitutes,synthetic membranes,cytokines,and matrix components,and most importantly avoid transmission of pathogens from human and animal products.CONCLUSION:These results encourage development of derivatives of hMSCs for wound care and re-epithelialization applications.

Advances in Experimental Studies on Treatment of Psoriasis by Traditional Chinese Medicine Zhou Yongsheng

Traditional Chinese medicine has demonstrated its strength in treating psoriasis, which is characterized by a variety of methods of treatment, flexible use of drugs, high efficacy, low recurrence, and few side-effects. Experimental studies on the mechanism governing the TCM treatment of psoriasis have been conducted at the cellular level and the molecular level. The studies on proliferation and differentiation of keratinocytes and the inhibitory effect against them, apoptosis, intercellular adhesion molecules, cytokine, and haemorheology indicate that the laboratory studies on the treatment of psoriasis have now entered a very high stage since the eighties. The studies on relationship between typing of psoriasis based on TCM differentiation of symptoms and signs and changes in some laboratory indexes have been carried out by some researchers to explore the inherent pathological changes in typing of psoriasis based on TCM differentiation of symptoms and signs and to provide scientific basis for the differentiation and typing under a unified standard. However, the present studies lack depth and scope in the methods. In future, the laboratory studies should be enhanced to go further into the principles governing the TCM treatment of psoriasis and to seek new drugs that will be even more effective for psoriasis and can bring its relapse under control.

Effect of lead on IL-8 production and cell proliferation in human oral keratinocytes

Objective:To investigate the effect of lead on the production of IL-8 and cell proliferation in normal human oral keratinocytes（NHKs）.Methods:NHKs were prepared as outgrowths from normal human buccal mucosa.The cells were treated with three concentrations of lead glutamate(4.5×10-5M,4.5×10-6M and 4.5×10-7M).NHKs grown in glutamic acid were used as control.The amounts of IL-8 secreted in the culture supernatants were evaluated at 12 and 24 h using enzyme-linked immunospecific assay（ELISA）.Cell proliferation was determined by the MTT colorimetric assay.Three cultures were used for each experiment,and three independent experiments were performed.Analysis of variance and Duncan’s multiple range tests were used for statistical analysis.Results:An elevation of IL-8 in culture supernatants of NHKs treated with lead at all concentrations at 12 and 24 h after exposure in a dose-dependent manner was revealed.A significant increase in cell numbers was observed only at 24 h exposed to 4.5×10- 5M lead glutamate.Conclusions:The capacity of NHKs,to secrete IL-8,enhanced by lead glutamate,is demonstrated here.Induction of cell proliferation is revealed only after exposure to high lead concentration.The elevation of secreted IL-8 is a probable initial sign for the acute inflammatory response and may be involved in the pathogenesis of lead stomatitis.

Flow Cytometric Analysis of the Toxicity of Nitrofen in Cultured Keratinocytes

Lactate dehydrogenase (LDH) release test, 3 H-thymidine (3 H-TdR) and 3 H-leucine (3 H-Leu) incoopration tests and flow cytometric analysis (FCM) of cell cycle were empoyed to elucidate cellular and molecular mechanism of nitrofen-induced toxicity in cultured keratinocytes.The results showed that cell morphologic damages were observed after exposure to 1.0 mmol/L and 10.0 mmol/L nitrofen. LDH release increased in a dose- and time-dependent manner. Depressions in 3H -TdR and 3 H-Leu incorpration were found even at 0.01 mmol/L, and increased with the exposure dose. Cell cycle was analyzed from the DNA- histogram with propidium iodde stain. The results showed that there was no pronounced alteration in cell cycle after cells exposed to 0.01 and 0.1 mmol/L nitrofen. At dose of 1.0 mmol/L, S phase cells increased 2 times of that of control. With the increase of dose, G2/M phase cells became to increase about 5 times of that of the control. At 1 .0 mmol/L, time course of cell cycle after exposure was observed. At the beginning of exposure, cells in S phase and G2/M phase were about 8 .7 % and 11 %. Following 24 h incubation with nitrofen, cells in S phase increased to 18.0% with almost no change in G2/M. 72 h after exposure, G2/M phase cells increased to 63 .3%. The forve results demonstrated that S phase and G2/M phase blockage in cultured keratinocytes after exposed to nitrofen seems of importance in the mechanism of nitrofen-induced toxicity.

Lipoxin A4 Inhibits Lipopolysaccharide-induced Production of Inflammatory Cytokines in Keratinocytes by Up-regulating SOCS2 and Down-regulating TRAF6

Liopxin A4（LXA4） is considered to be a crucial modulator in the inflammatory responses. In the present study, we aimed to study the effect of LXA4 on the inflammatory cytokines production induced by lipopolysaccharide（LPS） and the possible mechanism in normal human epidermal keratinocytes（NHEKs）. NHEKs were isolated and cultured. The expression of toll-like receptor 4（TLR4）, LXA4 receptor（ALXR） and aryl hydrocarbon receptor（Ah R） in NHEKs was detected by reverse transcription polymerase chain reaction（RT-PCR）. The m RNA and protein levels of tumor necrosis factor-alpha（TNF-α） and interleukin-1β（IL-1β） were determined in NHEKs stimulated by LPS（10 μg/m L） with or without preincubation with LXA4（100 nmol/L） for 30 min by real-time quantitative PCR（real-time q PCR） and enzyme-linked immunosorbent assay（ELISA）, respectively. The expression levels of tumor necrosis factor receptor-associated factor 6（TRAF6） and suppressors of cytokine signaling 2（SOCS2） m RNAs and proteins, and nuclear translocation of NF-k B-p65 were measured by real-time q PCR and Western blotting, respectively. The results showed that NHEKs expressed TLR4, ALXR and Ah R. LXA4 significantly inhibited the m RNA and protein expression levels of TNF-α, IL-1β and TRAF6 induced by LPS in NHEKs, and LXA4 obviously increased the expression of SOCS2 at m RNA and protein levels. The nuclear NF-k B-p65 protein expression induced by LPS was inhibited after preincubation with LXA4 in NHEKs. It was concluded that LXA4 inhibits the LPS-induced production of TNF-α and IL-1β in NHEKs by up-regulating SOCS2 and down-regulating TRAF6.

Enhancing effect of tazarotene on the HLA-DR expression of cultured human keratinocytes induced by interferon-gamma

Objective: To investigate the effect of tazarotene on the expression of HLA-DR induced by IFN-γ. Methods: (1) Keratinocytes from normal human skin were cultured in vitro;(2) Tazarotene, IFN-γ and the combination of the two compounds were incubated with the keratinocytes in medium, respectively. The expression of HLA-DR in keratinocytes was determined using immunocytochemistry techniques at 24h after incubation. Results: (1) There was rare expression of HLA-DR in normal human keratinocytes; (2) 10 -6mol/L tazarotene failed to induce the expression of HLA-DR in keratinocytes at 24h after incubation; (3) 500 U/ml IFN-γ obviously induced the HLA-DR expression in keratinocytes at 24h after treatment; (4) After 24h, 10 -7-10 -5 mol/L tazarotene had a significantly enhancing effect on the expression of HLA-DR induced by IFN-γ (P<0.005). Conclusion: Tazarotene up-regulates the expression of HLA-DR in keratinocytes cultured in vitro when combined with IFN-γ . Therefore, the reduction of HLA-DR positive keratinocytes in psoriatic lesions may be attributed to not direct interaction of tazarotene in combination with IFN-γ but other pathways.