Fig. 5

Repeated glucose challenge leads to abnormal glymphatic fluid transport in optic nerve of healthy mice. (A) Schematic of daily (except weekends) intraperitoneal administration of 1 M glucose solution or isotonic saline in healthy mice over a month followed by intravitreal (ITV) and cisterna magna (CM) injection of glymphatic-relevant tracers. (B) Representative plot of transient change of blood glucose levels in healthy awake mice after intraperitoneal injection of glucose (n = 5). One-way ANOVA, repeated measures with Geisser-Greenhouse correction. Significant differences to baseline (t = 0 min) indicated with the letter a. Significant differences to peak value (t = 30 min) indicated by letter b with *P ≤ 0.05. (C) Blood glucose levels of awake mice directly prior to undergoing the final experiment of intravitreal and intracisternal tracer injection (n = 5–6). Unpaired two-tailed t-test with Welch’s correction, ns = P > 0.05. (D-G) Representative macroscopic image of intravitreally (D) and intracisternally (G) injected tracer distributions along the optic nerve. EH) Average total tracer signal intensity over the entire length of the optic nerve (arbitrary units (A.U.), distance (µm) ascending from anterior to posterior) of ITV (E) and CM injected tracer (H). F-I) Total tracer signal intensity of entire optic nerves (left), tracer peak signal (middle), peak distance travelled (µm, ascending from anterior to posterior) (right) for ITV (F) and CM (I) injected tracer (n = 5–7). (F-I) Unpaired two-tailed t-test with Welch’s correction. *P ≤ 0.05 and ns = P > 0.05. All graphs show mean ± SD