OBJECTIVETo observe the change of caspase-8, caspase-9 activity and apoptosis rates in the process of trichloroethylene-induced damage in keratinocytes, and explore the tentative mechanism of apoptosis.

METHODSHuman keratinocytes were exposed to 0.125, 0.250, 0.500, 1.000 and 2.000 mmol/L trichloroethylene for 4, 8, 12 and 24 h. The inhibitive groups were pretreated with 100 micromol/L Z-LEHD-FMK (a specific inhibitor of caspase-9) for 1 h, and were stimulated with 2.000 mmol/l TCE for 12 h. MTT assay was used to detect the viability of different cells; The activity of caspase were calculated according to spectrophotometry; Change of the apoptotic rates was assessed by flow cytometer (FCM) after double-stained with Annexin V-FITC and propidium iodide (PI).

RESULTS(1) The minimum effective concentration for cell viability reduction was 0.125 mmol/L at 12 h and the shortest time required to produce a change was 4 h at a concentration of 2.000 mmol/L (compared with control group, P < 0.01). Cell viability in all the groups markedly decreased from 12 h to 24 h (P < 0.05). (2) The activity of caspase-8 in the various dosage groups at different times had no statistical difference compared with the control group, P > 0.01. (3) At 8 h, 1.000 and 2.000 mmol/L TCE groups could significantly enhance caspase-9 activity (P < 0.05). The caspase-9 activity in all the groups showed differences and was significantly higher than those of control cells when time was over 12 h (P < 0.05). (4) After exposing to different dosages of TCE for 12 h, the rate of apoptosis rose to (80.43 +/- 4.21)% with the increase of dosage, compared with the control group, (9.40 +/- 2.98)%, which showed a dose-effect relationship. (5) The cells pre-treated with caspase-9 inhibitor resulted in a decrease in the caspase-9 activity and apoptosis rates (compared with 2.000 mmol/L TCE exposed group, P < 0.01). However, there was no statistical significance in comparison with the control group (P > 0.05).

CONCLUSIONCaspase-9 may be an important mediator of apoptosis in keratinocytes induced by trichloroethylene.

Apoptosis ; drug effects ; Caspase 8 ; metabolism ; Caspase 9 ; metabolism ; Cells, Cultured ; Humans ; Keratinocytes ; drug effects ; enzymology ; pathology ; Trichloroethylene ; toxicity

OBJECTIVETo investigate the changes in cell proliferation and retinoic acid receptor gamma (RARgamma) mRNA expression in normal human keratinocytes after acitretin treatment and/or narrow-band ultraviolet-B irradiation.

METHODSNormal human keratinocytes were exposed to irradiation with 100 mJ/cm square NB-UVB and/or subsequent 12-hour incubation with 1x10(-6) mol/L acitretin, and the expression of RARgamma mRNA in the cells was examined using RT-PCR and real-time quantitative RT-PCR.

RESULTSA 0.9- and a 2.3-fold increase in RARgamma mRNA expression was induced in the cells by exposure to 100 mJ/cm square NB-UVB and 10(-6) mol/L acitretin, respectively, and the expression was synergistically enhanced by 2.8-fold after their combined treatment.

CONCLUSIONUpregulated expression of RARgamma mRNA can be associated with keratinocyte growth inhibition after treatment with acitretin and NB-UVB irradiation.

Acitretin ; pharmacology ; Cells, Cultured ; Humans ; Keratinocytes ; drug effects ; radiation effects ; RNA, Messenger ; metabolism ; Receptors, Retinoic Acid ; metabolism ; Ultraviolet Rays

OBJECTIVETo investigate the effects of bradykinin (BK) on the proliferation, apoptosis and differentiation of human keratinocyte (HKC) and the underlying mechanisms.

METHODSHKCs were cultured together with 1 x 10(-4) - 1 x 10(-9) mol/L of BK. With methyl thiotetrazole (MTT) and trypan blue staining it was shown that the BK in dose of 1 x 10(-4) mol/L possessed most powerful inhibitory effect, and the survival rate of HKC was 69.3%. Therefore, BK was employed in the dose of 1 x 10(-4) mol/L in the following studies. When the growth of HKCs reached the logarithmic phase, BK in the concentration of 1 x 10(-4) mol/L was added, and it was categorized as the test group (E). HKCs without BK served as the control group (C). The cell cycle and apoptosis were detected by flow cytometry after being cultured for 24 and 48 hours. The change in intracellular calcium [Ca(2+)](i) was determined by means of laser scanning confocal microscopy with calcium fluorescence probe Fluo-3/AM technique. The expression of HKC differentiation labeling protein keratin10 (K10) and involucrin were detected with Strept Avidin-Biotin Complex (SABC) immunocytochemical assay.

RESULTSThe cell ratio in G0/G1 phase in E group increased by 34.57% while in S phase decreased by 58.91% in reference to that in C group. The G1/S phase switching of HKCs was obviously inhibited by BK, and apoptosis was stimulated (apoptotic rate of 15.34% in E group vs 5.60% in C group, P < 0.05). The [Ca(2+)](i) increased transiently in HKCs by 163.0% in E group after 3 minutes of BK activation and decreased thereafter in reference to that in C group. The K10 expression in HKC was down-regulated in E group with positive cell rate of 2.20%, which was lower than that of C group (6.89%, P < 0.05).

CONCLUSIONThe cell cycle process of HKC could be inhibited by high concentration of BK with increased apoptosis and an increase in [Ca(2+)](i), which might be the mechanism of inhibition of growth of HKC in vitro. Furthermore, the epithelial regeneration and HKC differentiation can also be inhibited by BK.

Apoptosis ; drug effects ; Bradykinin ; pharmacology ; Cell Cycle ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Humans ; Keratinocytes ; cytology ; metabolism ; Keratins ; metabolism

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10 and 10 mol/L Ag at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5-60 min after exposure to Ag. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10 and 10 mol/L Ag, with 10 mol/L Ag markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.
Apoptosis ; drug effects ; Cell Line ; Cell Proliferation ; drug effects ; Fluorescent Antibody Technique ; Humans ; Keratinocytes ; cytology ; drug effects ; Proliferating Cell Nuclear Antigen ; metabolism ; Reactive Oxygen Species ; metabolism ; Silver ; pharmacology

OBJECTIVETo study the cellular and molecular mechanism of gasoline-induced adverse effects on skin, particularly on keratinocyte and fibroblast in vitro.

METHODSThe primary cell culture of keratinocyte and fibroblast were treated with 0, 0.001%, 0.01%, 0.1% and 1.0% gasoline, respectively. (3)H-thymidine ((3)H-TdR), (3)H-leucine ((3)H-Leu), (3)H-proline ((3)H-Pro) and (14)C-linoleic acid incorporation tests were applied to elucidate their capacity of synthesizing DNA, protein and sebum.

RESULTSThe incorporation of (3)H-TdR in keratinocyte and (3)H-TdR and (3)H-Pro in fibroblast inhibited significantly after exposure to 0.01% gasoline (P < 0.05), with inhibition rates 68.5%, 45.1% and 40.6% for (3)H-TdR in keratinocyte, and (3)H-TdR and (3)H-Pro in fibroblast, respectively. Significant depression in incorporation of (3)H-Leu and (14)C-linoleic acid in keratinocyte were found even in the group treated with 0.001% gasoline (P < 0.05), with inhibition rates of 20.2% and 41.2%, respectively.

CONCLUSIONSSolvent gasoline has certain toxic effect on keratinocyte and fibroblast, intervening their normal metabolic and physiological process and affecting their ability of synthesizing DNA, protein and sebum, and their physiological functions, which could be one of the mechanisms causing skin damage by gasoline. The results also indicated that keratinocyte was more susceptible to gasoline than fibroblast.

Animals ; Cells, Cultured ; DNA ; biosynthesis ; genetics ; Dose-Response Relationship, Drug ; Fibroblasts ; cytology ; drug effects ; metabolism ; Gasoline ; toxicity ; Keratinocytes ; cytology ; drug effects ; metabolism ; Proteins ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley ; Sebum ; drug effects ; metabolism

BACKGROUNDTrichophyton rubrum is superficial fungi characteristically confined to dead keratinized tissues. These observations suggest that the soluble components released by the fungus could influence the host immune response in a cell in contact-free manner. Therefore, this research aimed to analyze whether the culture supernatant derived from T. rubrum grown in the nail medium could elicit the immune response of keratinocyte effectively.

METHODSThe culture supernatants of two strains (T1a, T XHB ) were compared for the β-glucan concentrations and their capacity to impact the innate immunity of keratinocytes. The β-glucan concentrations in the supernatants were determined with the fungal G-test kit and protein concentrations with bicinchoninic acid protein quantitative method, then HaCaT was stimulated with different concentrations of culture supernatants by adopting morphological method to select a suitable dosage. Expressions of host defense genes were assessed by quantitative polymerase chain reaction after the HaCaT was stimulated with the culture supernatants. Data were analyzed with one-way analysis of variance, followed by the least significant difference test.

RESULTSThe T. rubrum strains (T1a and T XHB ) released β-glucan of 87.530 ± 37.581 pg/ml and 15.747 ± 6.453 pg/ml, respectively into the media. The messenger RNA (mRNA) expressions of toll-like receptor-2 (TLR2), TLR4, and CARD9 were moderately up-regulated in HaCaT within 6-h applications of both supernatants. HaCaT cells were more responsive to T1a than T XHB . The slight increase of dendritic cells-specific intercellular adhesion molecule 3-grabbing nonintegrin expression was faster and stronger, induced by T1a supernatant than T XHB . The moderate decreases of RNase 7, the slight up-regulations of Dectin-1 and interleukin-8 at the mRNA level were detected only in response to T1a rather than T XHB . After a long-time contact, all the elevated defense genes decreased after 24 h.

CONCLUSIONThe culture supernatant of T. rubrum could directly and transiently activate the innate immune response of keratinocytes.

Cell Line, Tumor ; Culture Media, Conditioned ; pharmacology ; Humans ; Immunity, Innate ; drug effects ; Keratinocytes ; drug effects ; metabolism ; Trichophyton ; metabolism ; beta-Glucans ; metabolism

BACKGROUNDElastin derived peptides can regulate melanocyte precursor development. Ultraviolet irradiation, infrared radiation and heat can increase the synthesis of tropoelastin in human skin epidermis. The aim of this study was to investigate whether the over expressed tropoelastin in epidermis has some role in melanogenesis of melanocytes.

METHODSA375 human melanoma cells were treated with different concentrations of kappa elastin for 24 hours. A375 human melanoma cells were randomly assigned to control, kappa elastin, and lactose pre-incubated groups. The cell viabilities were detected by the methyl thiazoleterazolium assay. Melanin content and tyrosinase activity in A375 melanoma cells were measured. The expressions of endothelin B receptor (ET(B)R) mRNA and c-kit mRNA in A375 melanoma cells were measured by quantative reverse transcription polymerase chain reaction.

RESULTSFifty µg/ml of kappa elastin significantly increased the melanin content by 56.64% compared with the control (P < 0.05). Kappa elastin increased cellular tyrosinase activity by 46.73% compared with the control at 24 hours (P < 0.05). Kappa elastin increased the expressions of ET(B)R and c-kit mRNA levels by 2.13-fold and 2.47-fold compared with the controls, respectively. When pre-incubating cells with a lactose solution (10 mmol/L), the inhibition on melanin production was 34.96% compared with the kappa elastin group (P < 0.05), tyrosinase activity was inhibited by 29.93% compared with kappa elastin group (P < 0.05), and the expressions of ET(B)R mRNA and c-kit mRNA were decreased by 1.56-fold and 0.82-fold compared with kappa elastin group, respectively.

CONCLUSIONKappa elastin increased the melanogenesis in A375 melanoma cells via the stimulation of tyrosinase activity and the expression of ET(B)R and c-kit. The over expressed tropoelastin produced by keratinocytes might play a role in melanogenesis of epidermal melanocytes.

Cell Line, Tumor ; Cell Survival ; drug effects ; Elastin ; pharmacology ; Humans ; Keratinocytes ; drug effects ; Melanins ; metabolism ; Melanoma ; Proto-Oncogene Proteins c-kit ; metabolism ; Receptor, Endothelin B ; metabolism

OBJECTIVETo observe the effect of shikonin on the proliferation of human keratinocytes induced by IL-17 and secretion of chemokines, in order to discuss the mechanism of Shikonin in the treatment of psoriasis.

METHODIn vitro cultured HaCaT cells were stimulated by IL-17A (200 μg x L(-1)) and mixed with different concentrations (2, 1 mg x L(-1)) of shikonin for 24 hours. The cell proliferation was detected by CCK-8 assay. Cell secretion inflammatory factor interleukin-23 (IL-23) was detected by ELISA. The expressions of intracellular chemokines CXCL1, CXCL2, CCL20 and 6-defensin 4 (DEFB4) were detected by Real-time PCR.

RESULTShikonin (2,1 mg x L(-1)) could distinctly inhibit HaCaT cell proliferation induced by IL-17A, with statistical difference (P < 0.01). Each shikonin group showed decreases in the secretion of IL-23 and inhibition in expressions of intracellular CXCL1, CXCL2, CCL20 and DEFB4.

CONCLUSIONShikonin could inhibit HaCaT cells proliferation induced by IL-17 and secretion of relevant cytokines and recruit leukocytes by inhibiting chemokines, so as to show the effect in treating psoriasis.

Cell Line ; Cell Proliferation ; drug effects ; Chemokines ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Interleukin-17 ; genetics ; metabolism ; Keratinocytes ; cytology ; drug effects ; metabolism ; Naphthoquinones ; pharmacology

The aim of this paper was to investigate the effect of terpene penetration enhancers on membrane fluidity and membrane potential using HaCaT keratinocytes, and study the potential mechanisms of these terpene compounds using as natural transdermal penetration enhancer. Six terpene compounds, namely menthol, limonene, 1,8-cineole, menthone, terpinen-4-ol and pulegone, were chosen in this study on account of their good penetration-enhancement activities. The cytotoxicity of these terpene compounds was measured using an MTT assay. The fluorescence recovery after photobleaching (FRAP) technique was employed to measure the change of membrane fluidity of HaCaT cells. The flow cytometer was used to study the alteration of membrane fluidity of HaCaT cells, and investigate the effect of terpene compounds on intracellular Ca2+. It was found that 6 terpene compounds possessed low cytotoxicity in comparison to the well-established and standard penetration enhancer azone. Those terpene compounds could significantly enhance HaCaT cells membrane fluidity and decrease HaCaT cells membrane potentials. Meanwhile, after treated with various terpene compounds, the Ca2(+)-ATPase activity and intracellular Ca2+ of HaCaT cells was decreased significantly. Terpene penetration enhancers perhaps changed the membrane fluidity and potentials of HaCaT cells by altering the Ca2+ balance of the cell inside and outside, resulting in the low skin permeability to increase the drug transdermal absorption.
Cell Line ; Drugs, Chinese Herbal ; pharmacokinetics ; Humans ; Keratinocytes ; drug effects ; metabolism ; Membrane Fluidity ; drug effects ; Skin Absorption ; drug effects ; Terpenes ; pharmacokinetics

BACKGROUNDKeratinocytes play a crucial role in the biological function of skin barrier. The relationship between sodium lauryl sulfate (SLS) and keratinocytes has been studied. However, the cytotoxicity and effects of sodium dodecyl benzene sulfonate (SDBS), a common detergent similar to SLS, on keratinocytes are still not known. This study aimed to investigate the effects of SDBS on cytotoxicity and expression of proinflammatory cytokines in cultured human keratinocytes.

METHODSThis study was carried out using the keratinocytes cell line, HaCaT cells. The cytotoxicity of SDBS on HaCaT cells was evaluated with cell counting kit-8 (CCK-8) and phase-contrast microscopy. After exposure to different concentrations of SDBS, the total RNA of the HaCaT cells was extracted for evaluating the relative mRNA expression of IL-1α, IL-6, IL-8, and TNF-α by qPCR. The supernatants of cells were collected for measuring the levels of IL-6 and IL-8 by enzyme-linked immunosorbent assay (ELISA).

RESULTSSDBS at concentrations of 20 µg/ml and over showed direct cytotoxicity and induced morphological changes of the HaCaT cells. The mRNA expressions of IL-1α, IL-6, IL-8, and TNF-a in different concentrations of SDBS at different time were comparable with that of controls. SDBS at concentrations of 5, 10, and 15 µg/ml had no significant effects on IL-6 and IL-8 excretion from HaCaT cells after 24-hour exposure. Moreover, no significant effects on the IL-6 and IL-8 excretion were found after 10 and 15 µg/ml SDBS stimulations for 6, 12, and 24 hours, respectively.

CONCLUSIONSDBS at higher concentrations had cytotoxicity on HaCaT cells but had no effects on the mRNA expression of IL-1α, IL-6, IL-8, and TNF-a, that was different from SLS.

Benzenesulfonates ; pharmacology ; Cell Line ; Enzyme-Linked Immunosorbent Assay ; Humans ; Interleukin-1alpha ; metabolism ; Interleukin-6 ; metabolism ; Interleukin-8 ; metabolism ; Keratinocytes ; drug effects ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism