2020 年 25 巻 1 号 p. 1-12
Our study explored the use of translucent larval skin mutants of the silkworm "o06" strain as a possible substitute for the mouse hyperuricemia model in medical studies. The uric acid (UA) contents were measured in the o06 and Gunma200 (control) strains. The hemolymph UA level was analyzed using high-performance liquid chromatography with ultraviolet detection, which allows for high-sensitivity microliter analysis. The hemolymph of the mutants (at the 5th instar) contained more (4–6 mg/dL) UA than the normal silkworms.
The UA level in hemolymph of the mutant was affected by diet, but the level of allantoin (Alla) was not. UA was excreted as feces, but Alla was not detected in larval urine. This indicates that the activity of uricase was suppressed so that Alla in hemolymph was maintained at a specific level, and UA was not metabolized but accumulated in hemolymph at 3 to 6day-old mutants. Allopurinol and other treatments effectively reduced the UA levels in the mutants. Moreover, the dose response data suggested that our model can be used for research on reagents that reduce blood UA levels in hyperuricemia. Our results indicate that the o06 strain is a potential substitute for the mouse hyperuricemia model in medical research.
