Font Size: 

Background: Atopic dermatitis (AD) is a common chronic inflammatory skin disease that has increased in industrialized countries over the last 30 years.  AD is characterized by chronic and relapsing inflammatory dermatitis, and pruritic and eczematous skin lesions of the body.  A number of therapeutic agents for AD such as steroids, immunosuppressive agents and anti-histamine agents are commercially available.  However, these therapeutic agents infrequently cause regional side effects, e.g. atrophia cutis, capillary dilatation, moon face and osteoporosis.  Therefore, novel therapeutic agents for AD symptoms without the adverse effects are necessary.  In our previous report, 0.05% (w/v) sacran exhibited an anti-allergic effect on dinitrofluorobenzene (DNFB)-induced AD-like disease in mice.  However, sacran shows high viscosity due to its huge molecular weight (> 10 million).  Objective: In this study, we prepared the low-molecular sacran through sonication and acid hydrolysis, and evaluated its anti-inflammatory effect on DNFB-induced AD model mouse.  Materials and Methods: Low-molecular sacran was prepared by sonication for 30 min and agitation with trifluoroacetic acid at 100ºC for 4 h.  The viscosity of low-molecular sacran was measured by a rotational viscometer.  To evaluate in vivo anti-inflammatory effect, dorsal skin and ear of Nc/Nga mice (6 weeks, female) were treated with DNFB and 0.05% (w/v) low-molecular sacran.  Then, severity scoring of atopic dermatitis (SCORAD) score was evaluated by macroscopic observation.  Results: The viscosity of low-molecular sacran was lower than that of sacran.  In the AD model mice, 0.05% (w/v) low-molecular sacran improved SCORAD score and suppressed an increase of ear thickness.  Importantly, the anti-inflammatory effect of low-molecular sacran was comparable to that of sacran and prednisolone.  Conclusion: Low-molecular sacran has the potential as a therapeutic agent for AD.

Key words: Sacran, Low-molecular sacran, Atopic dermatitis, Anti-inflammatory effect