Fig. 6

CSF tracer drainage via extracranial lymphatics to systemic blood circulation during BPL. A, Experimental scheme and timeline of afferent lymphatic vessel ligation, FD40 injection and blood sampling. CM infusion of FD40 began ~ 20 min after lymphatic vessel (LV) ligation, followed with first blood sampling (3 min after the infusion), 10-min BPL or saline treatment (2 min later) and final blood sampling. B, An illustration of afferent LV ligation (crossed red lines) which obstructs tracer uptake (yellow spheres) into a lymphatic efflux pathway (yellow arrows) and deep cervical lymph nodes (dcLNs). C, Drainage of FD40 into a dcLN (white dashed lines) via the afferent lymphatic vessel is blocked after ligation. D, FD40 drainage into a dcLN on the sham-operated side of the same animal as in C. E, F, Blood- (BP) and intracranial pressure (ICP) measurements during BPL with sodium nitroprusside (SNP), multiple unpaired t-tests with Welch’s correction. G, Concentration changes of FD40 in blood after BPL with SNP in sham-operated and ligated groups, two-way ANOVA with Šidák’s multiple comparisons. n = 5 mice per group. C, D, Scale bar, 1 mm. E–G, *P < 0.05, ns = non-significant. Filled and open circles represent individual mice (G)