Cell-mediated immune suppression effect of rocket kerosene through dermal exposure in mice / 解放军医学杂志

ABSTRACT

ObjectiveTo study the effect of cell-mediated immune suppression effect of rocket kerosene (RK) through dermal application in mice. MethodsSkin delayed type hypersensitivity (DTH) was used to observe the relation of the RK amount the skin exposed and the cellular immune inhibitory function. Different amount of the undiluted fuel was smeared directly onto the dorsal skin of mice. Mice in negative and positive control groups were treated with acetone. After the last exposure, all the mice except those in negative control group were allergized by evenly smearing with 1% dinitrofluorobenzene (DNFB) solution on their dorsum. Five days after allergy, 1% DNFB solution was smeared onto right ear of all mice to stimulate the allergic reaction. Twenty-four hours after attack, the auricle swelling, spleen index and thymus index in corresponding mice were determined. In the first series of experiments, different dosages of RK were applied once, and the ICR mice were randomly divided into negative control group, positive control group and experimental group (0.5ml/kg.BW×1, 1ml/kg.BW×1 and 2ml/kg.BW×1 group). In the second series of experiments, the certain and same dosage of RK was applied for different times, and the ICR mice were randomly divided into negative control group, positive control group and experimental group (0.5ml/kg.BW×1, 0.5mL/kg.BW×2, 0.5ml/kg.BW×3, 0.5ml/kg.BW×4 and 0.5mL/kg.BW×5 group). In the third series of experiments, the different dosages of RK were applied more than once, and the ICR mice were randomly divided into negative control group, positive control group and experimental group (0.5ml/kg.BW×5, 1ml/kg.BW×5 and 2ml/kg.BW×5 group). Lymphocyte proliferation experiment in vitro was conducted to observe the persistent time of the cell-mediated immune suppression in mice by RK dermal exposure. The lymphocyte proliferation induced by concanavalin A (Con A) was analyzed by MTT assay, and T lymphocyte subsets (CD3+, CD4+ and CD8+) in peripheral blood and spleen lymphocyte cell cycle were analyzed by flow cytometry. ResultsRK dermal exposure (1ml/kg.BW×1) alleviated the ear edema, suppressed the spleen index elevation and thymus index reduction caused by DNFB sensitization in ICR mice, and the suppression effect increased with exposed dosage and time increasing. RK dermal exposure (1ml/kg.BW×1) suppressed ConAinduced spleen lymphocyte proliferation, and the effect persisted for 20d (P+/CD8+ ratio in peripheral blood was lower in RK group than in negative control group (P<0.05). ConclusionDermal exposure of RK may have cell-mediated immunotoxicity.