Fig 4. BDNF repairs podocyte damage in Zebrafish larvae.

A) Transmission Electron Microscopy of representative glomeruli from 5 dpf larvae. In control conditions (upper left image) regularly spaced podocyte foot processes cover the basement membrane (red arrows). After vehicle treatment (upper right image) very few podocyte foot processes can barely be recognized (red arrows) and most of the basement membrane looks diffusely covered by the podocyte cytoplasm. After BDNF treatment (lower left image) podocyte foot processes look similar to the control condition (red arrows). Scale bars 1μm.

B) Real-Time RT-PCR for nephrin (upper graph) and TrkB1 (lower graph). mRNA was obtained from 5 dpf Zebrafish larvae in control conditions and after vehicle and BDNF treatment (10 animals per group). Vehicle treatment determines a significant reduction of both nephrin and TrkB mRNAs. Their expression after BDNF treatment is similar to controls. Y axis: normalized fold expression.

C) The images on the left show distribution of injected fluorescent dextran at 24 hours post-injection (hpi). As predicted, fluorescence is distributed throughout the body in a zebrafish larva in control conditions (NT). Incubation with adriamycin dose-dependently (ADR20, ADR30) decreases fluorescence at 24hpi, while accumulation due to pericardial edema can be seen in the cardiac area. The graph on the right illustrates measurements of eye fluorescence at injection (0 hpi) and after 24 and 48 hours. Measurements were taken from 30 animals per group.

D) Eye fluorescence at 24h is significantly lower in larvae receiving medium alone after adriamycin incubation. BDNF treatment restores fluorescence intensity at control levels. Measurements were taken from 30 animals per group. *p<0.05; **p<0.01.