Figure 2.

Dietary phenylalanine restriction can reduce the accumulation of phenylpyruvate and promote diabetic wound healing

(A) Schematic representation of diabetic wound model mice fed different phenylalanine diets. n = 12 for each group.

(B) Detection of the indicated metabolites in cutaneous wounds from different groups by metabolic mass spectrometry (n = 3).

(C) Recorded weights of diabetic mice fed a phenylalanine restriction diet for 1 week before wound model generation (n = 12).

(D) Representative images of cutaneous wounds of diabetic mice on days 0, 4, 8, 12, and 16 after wound model generation by surgical excision.

(E) Percentage of wound sizes were quantified by using ImageJ software and were calculated by the percentages of wound closure compared to day 0 wound size.

(F) Cutaneous wound sections from different groups were subjected to H&E and Masson’s trichrome staining and IHC staining with Ki-67, α-SMA, CD31, and NLRP3 antibodies. Samples were collected at 8 days after wound model generation. n = 3 mice for sampling at the indicated time points. Scale bar, 100 μm.

(G) Histological staining analysis showing relative epidermal thickness (n = 3).

(H) Statistical analysis of NLRP3 staining in cutaneous wounds from different groups (n = 3).

(I and J) Representative immunofluorescence images and statistical analysis showing macrophage infiltration in cutaneous wounds on day 8. n = 3 mice in each group. Scale bar, 20 μm.

(K and L) Flow cytometry analysis of macrophage infiltration in cutaneous wounds from different groups on days 8 and 12. The representative histogram shows the levels of F4/80+CD86+ cells in cutaneous wounds from these groups. Statistical analysis indicates the MFI of CD86 (n = 3).

(M) Western blot images and analysis showing NLRP3 protein expression levels in cutaneous wounds from these groups (n = 3). Data are shown as mean ± SD. ∗p < 0.05, ∗∗p < 0.01; n.s., not significant.