Detection of endogenous and food-derived collagen dipeptide prolylhydroxyproline (Pro-Hyp) in allergic contact dermatitis-affected mouse ear

Figures & data

Fig. 1. Induction of contact dermatitis.

Notes: Contact dermatitis was induced by applying DNFB or vehicle every 3 days to the right ear of mice and the temporal changes of ear thickness were measured. The results are presented as mean ± SD (n = 6).

Fig. 2. Contents of Hyp-Gly and Pro-Hyp in mouse ear.

Notes: (A, B): Hyp-Gly (A) and Pro-Hyp (B) in the non-treated left ear of mice treated with vehicle (V) or DNFB on the right ear for 9 or 18 days. (C, D): Hyp-Gly (C) and Pro-Hyp (D) in the right ear treated with vehicle (V) or DNFB for 9 or 18 days. The results are presented as mean ± SD (n = 6). Values in the same figure not sharing a common letter above the bar are significantly different from each another, p < 0.05.

Fig. 3. Pro-Hyp in plasma after ingestion of Pro-Hyp.

Notes: Pro-Hyp was orally administered at a dose of 400 μg/20 g body weight and measured in the plasma. The results are presented as mean ± SD (n = 3).

Fig. 4. Contents of [¹³C₅,¹⁵N]Pro-Hyp and [¹³C₅,¹⁵N]Pro in the ears of mice with contact dermatitis.

Notes: The right ear of mice was treated with DNFB (+) and the left ear was non-treated (−) for 18 days. On day 18, the mice were orally administered water, [¹³C₅,¹⁵N]Pro-Hyp or [¹³C₅,¹⁵N]Pro, and the contents of the labeled Pro-Hyp (A) and Pro (B) in each ear were determined 4 h after ingestion (n = 4). *p < 0.05.