Non-animal photosafety screening for complex cosmetic ingredients with photochemical and photobiochemical assessment tools.

Previously, a non-animal screening approach was proposed for evaluating photosafety of cosmetic ingredients by means of in vitro photochemical and photobiochemical assays; however, complex cosmetic ingredients, such as plant extracts and polymers, could not be evaluated because their molecular weight is often poorly defined and so their molar concentration cannot be calculated. The aim of the present investigation was to establish a photosafety screen for complex cosmetic ingredients by using appropriately modified in vitro photosafety assays. Twenty plant extracts were selected as model materials on the basis of photosafety information, and their phototoxic potentials were assessed by means of ultraviolet (UV)/visible light (VIS) spectral analysis, reactive oxygen species (ROS)/micellar ROS (mROS) assays, and 3T3 neutral red uptake phototoxicity testing (3T3 NRU PT).

Non-animal photosafety assessment approaches for cosmetics based on the photochemical and photobiochemical properties.

The main purpose of the present study was to establish a non-animal photosafety assessment approach for cosmetics using in vitro photochemical and photobiochemical screening systems. Fifty-one cosmetics, pharmaceutics and other chemicals were selected as model chemicals on the basis of animal and/or clinical photosafety information. The model chemicals were assessed in terms of photochemical properties by UV/VIS spectral analysis, reactive oxygen species (ROS) assay and 3T3 neutral red uptake phototoxicity testing (3T3 NRU PT).

Changes of cell-surface thiols and intracellular signaling in human monocytic cell line THP-1 treated with diphenylcyclopropenone.

Changes of cell-surface thiols induced by chemical treatment may affect the conformations of membrane proteins and intracellular signaling mechanisms. In our previous study, we found that a non-toxic dose of diphenylcyclopropene (DPCP), which is a potent skin sensitizer, induced an increase of cell-surface thiols in cells of a human monocytic cell line, THP-1. Here, we examined the influence of DPCP on intracellular signaling.

Further verification of an in vitro tier system for the identification of cosmetic ingredients that are not ocular irritants.

A tier evaluation system for the identification of cosmetic ingredients that are not ocular irritants was applied to 59 cosmetic ingredients, for which in vivo data were available. The tier system employs monolayer cultures of SIRC cells, an established cell line originally derived from rabbit cornea, and a threedimensional living dermal model (LDM; MATREX(TM)), which consists of human dermal fibroblasts in a contracted collagen lattice. The effects of ingredients on monolayer cultures of SIRC cells were determined by Crystal Violet staining (in the SIRC-CVS assay), and the effects on the LDM were measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (in the LDM-MTT assay).

Sirc-cvs cytotoxicity test: an alternative for predicting rodent acute systemic toxicity.

An in vitro crystal violet staining method using the rabbit cornea-derived cell line (SIRC-CVS) has been developed as an alternative to predict acute systemic toxicity in rodents. Seventy-nine chemicals, the in vitro cytotoxicity of which was already reported by the Multicenter Evaluation of In vitro Toxicity (MEIC) and ICCVAM/ECVAM, were selected as test compounds. The cells were incubated with the chemicals for 72 hrs and the IC(50) and IC(35) values (microg/mL) were obtained.

Quantitative measurement of spliced XBP1 mRNA as an indicator of endoplasmic reticulum stress.

The unfolded protein response (UPR) events triggered by the accumulation of unfolded protein in endoplasmic reticulum (ER) activate the three UPR signaling pathways mediated by IRE1, ATF6 and PERK. Spliced XBP1 mRNA induced by activated IRE1 is translated to the protein, a potent transcription factor that induces BiP expression. XBP1 is also induced by activated ATF6.

Nylon ear tags for individual identification of guinea pigs.

Although customarily used for individual identification of guinea pigs, metal ear tags are suboptimal because frequent detachment often results in wounds with inflammation and secondary bacterial infections. Using 60 6-week-old individually housed male Dunkin-Hartley guinea pigs (Cavia porcellus), we conducted an 8-week study to determine the stability of a new nylon tag attached to the center of the pinna. The subsequent tissue reaction was compared with those due to metal tags attached either at the center or near the edge of the pinna.