Fig. 4: Stroke increases ciDNA and promotes lymphocyte loss in PP.

a, Quantification of plasma DNA 6 h and 24 h after sham surgery or stroke using Qubit assays (n = 5−12 per group, two−tailed Mann−Whitney U-test, ***P = 0.0002, *P = 0.0459). b, Numbers of B cells in PP 24 h after sham surgery or stroke in DNase-I-treated and vehicle-treated mice analyzed by flow cytometry (n = 3−6 per group, ordinary one-way ANOVA with Bonferroni’s multiple comparisons tests, sham+DNase-I versus stroke+DNase-I non-significant P > 0.9999, sham control versus sham+DNase-I non-significant P > 0.9999, ****P < 0.0001). c, Numbers of T cells in PP 24 h after sham operation or stroke in DNase-I-treated and vehicle-treated mice (n = 3−7 per group, ordinary one-way ANOVA with Bonferroni’s multiple comparisons tests, sham+DNase-I versus stroke+DNase-I non-significant P > 0.9999, sham control versus stroke control ****P < 0.0001, stroke control versus stroke+DNase-I ****P < 0.0001). d, Brain infarct volumes in DNase-I-treated and untreated mice at 24 h (n = 6−7 per group, two−tailed Mann−Whitney U-test, non-significant P = 0.2343). e, 3D reconstruction LSFM images of CD19⁺ B cells and CD3⁺ T cells in PP after sham, stroke and stroke+DNase-I-treated mice; scale bar, 500 µm. f, Quantification of CD19⁺ B cell follicle volume (n = 4−6 PP per intestinal segment, two-tailed Mann−Whitney U-test, stroke versus stroke+DNase-I duodenum non-significant P = 0.9048, stroke versus stroke+DNase-I jejunum *P = 0.0173, stroke versus stroke+DNase-I ileum *P = 0.0317). g, T cell zone volume in duodenum, jejunum and ileum 24 h after stroke or stroke+DNase-I treatment (n = 4−6 PP per intestinal segment, two-tailed Mann−Whitney U-test, stroke versus stroke+DNase-I duodenum non-significant, P = 0.2, stroke versus stroke+DNase-I jejunum *P = 0.0173, stroke versus stroke+DNase-I ileum *P = 0.0317). h, Schematic of the experimental paradigm. Mice underwent stroke or sham operation and were euthanized after 6 h to collect blood plasma. Cell cultures from PP were prepared and treated with the plasma of sham or stroke mice for 12 h. In the third condition, plasma of stroke mice was treated with DNase-I before addition to the cell cultures, and quantification of caspase-3/7-expressing cells was performed by flow cytometry. i, The percentages of caspase-3/7⁺ B and T cells in PP cell cultures incubated with the plasma of sham or stroke mice or DNase-I-treated stroke plasma (n = 5−10 mice per group, ordinary one-way ANOVA, CD19⁺ sham versus stroke ****P < 0.0001, stroke versus stroke+DNase-I ***P = 0.0002, CD3⁺ sham versus stroke ****P < 0.0001, stroke versus stroke+DNase-I **P = 0.0037). Data are mean ± s.d., Shapiro–Wilk normality tests.