Résumé
Objective To analyze and compare results of local lymph node assays (LLNA) between BALB/c and CBA mice.Methods 4 chemicals (2,4-dinitrochlorobenzene, eugenol, hexyl cinnamic aldehyde and isopropanol) and 3 cosmetics were applied to the dorsum of both ears of Balb/c and CBA mice for three consecutive days.BrdU solution was injected inter-peritoneally on day 5.On day 6, the bilateral draining auricular lymph nodes were excised and made into single cell suspension, the lymph cell proliferation was measured by BrdU ELISA kit.Results 2,4-dinitrochlorobenzene, eugenol, hexyl cinnamic aldehyde and NO.3 perm agent pretended positive for both strains, EC1.6 values of three chemicals were found to be 0.08% (very strong), 4.02% (moderate), 6.68% (moderate) and 0.07% (very strong), 6.08% ( moderate), 8.89% ( moderate) for BALB/c and CBA mice respectively.Isopropanol, NO.1 and NO.2 cosmetics pretended to be non-sensitizers with SI <1.6 for both strains.Conclusion This study showed that BALB/c mouse was essentially equal to CBA for LLNA: BrdU-ELISA, which suggested that BALB/c mouse was a good alternative for CBA used in chemicals and cosmetics allergenic evaluation.
Résumé
Objective To establish a rapid modified Local lymph node assay ( LLNA) for the sensitization and irritancy potential of chemicals, and evaluate cosmetics products. Methods 3 kinds of chemicals ( 2 , 4-Dinitrochlorobenzene ( DNCB) , Eugenol and Hexyl cinnamic aldehyde) and 3 kinds of cosmetics were selected.The dorsal sides of both ears of female BALB/c mice were treated with 25μL/ear of the test solutions on 3 consecutive days, and the thickness of each ear was measured.BrdU solution was injected inter-peritoneally on day 5.On day 6, each auricle was weighed, the bilateral draining auricular lymph nodes were excised and weighed, then made into single cell suspension.BrdU was measured by ELISA using a commercial kit.Results Ear swelling and auricle weight of DNCB ( 1.0%) , Eugenol ( 25% and 50%) and number 3 cream foundation increased significantly ( P <0.05 or P <0.01), which may be considered as irritants.The others were negative.For LLNA, three chemicals and number 3 cream foundation pretended positive.Conclusion The combined LLNA/ear swelling/ear weight assay appears to be a reliable predictor of sensitization and irritancy potential, and is expected to play an important role in safety evaluation of cosmetics.
Résumé
Objective To establish a method of murine local lymph node assay (LLNA) combined with measurement of ear swelling for the identification of photosensitive agents. Methods The female BALB/c mice received test chemicals or vehicle alone on the back skin of both ears and then were exposed to UVA irradiation on three consecutive days. The post-auricular lymph nodes draining the ear tissue were excised 24 h following the last irradiation. Lymph node cell counts and lymphocyte proliferative rates were determined, which indicated lymph node hyperplasia. While ear swelling was also measured, to reveal skin irritating reactions. Some cytokines (IFN-?, IL-2 and IL-4) released by the draining lymph node were also analyzed by ELISA. Results Tetrachlorosalicylanilide, a strong photoallergen, caused lymph node hyperplasia without ear swelling. The mild photoallergen (6-methylcoumarin) showed neither lymph node proliferation nor ear swelling reactions. But 8-methoxypsoralen, a phototoxic substance, induced both lymph node hyperplasia and ear swelling. The level of IL-4 was significantly increased when the mice were previously sensitized with tetrachlorosalicylanilide (P