SACRAN PROTECTS SKIN AGAINST POLLUTANTS 25 Figure 4. Suppressive effects of polysaccharides on CYP1A1 mRNA expression levels induced by tobacco. HaCaT keratinocytes were cultured in DMEM containing PBS diffused with tobacco smoke through fi lters treated with or without sacran or HA. After 24 h, total RNA was extracted and CYP1A1 mRNA levels were determined by real-time PCR. Each value represents the mean ± SD of four experiments. **p 0.01. Control(-) denotes sham-treated cells (PBS(-) nontreated with tobacco smoke) and Control(+) denotes cells treated with tobacco smoke diffused through a nontreated fi lter.

JOURNAL OF COSMETIC SCIENCE 26 effects on the amelioration of cytotoxicity, sacran gave a signifi cantly higher reduction in cytotoxicity than HA (Figure 5). Regarding levels of intracellular oxidation, tobacco smoke strongly elevated intracellular ROS levels associated with intracellular CPs. Sacran signifi cantly suppressed the eleva- tion of intracellular ROS levels (Figure 6) and intracellular CPs (Figure 7). Although HA reduced levels of intracellular ROS, it failed to signifi cantly suppress levels of intracel- lular CPs. BARRIER FUNCTION OF POLYSACCHARIDES AGAINST TOBACCO SMOKE In the ex vivo study, corneocytes exposed to tobacco smoke for 2 h had increased levels of CPs. Polysaccharide-treated corneocytes showed signifi cantly lower levels of CPs af- ter exposure to tobacco smoke than nontreated corneocytes. In addition, when exposed to tobacco smoke, sacran gave signifi cantly lower CP levels in corneocytes than HA (Figure 8). Figure 5. Amelioration of the cytotoxicity induced by tobacco smoke on HaCaT keratinocytes. HaCaT ke- ratinocytes were cultured in DMEM containing PBS diffused with tobacco smoke through fi lters treated with or without sacran or HA for 24 h at 37°C. Cell viability was measured using the neutral red assay and is ex- pressed as a percentage against sham-treated cells (Control(-)). Each value represents the mean ± SD of six experiments. Wilcoxon rank-sum test, ***p 0.001.