Journal: Antioxidants

Article Title: Oxidative Stress Plays an Important Role in Glutamatergic Excitotoxicity-Induced Cochlear Synaptopathy: Implication for Therapeutic Molecules Screening

doi: 10.3390/antiox13020149

Figure Lengend Snippet: BDNF, NT3, and BDNF mimetics boost synapse regeneration or repair. ( A – C ): Maximum intensity projections of confocal z-stacks of IHCs of the cochlear explants labeled with anti-CtBP2 (green), anti-PSD95 (red), and anti-VGLUT3 (blue) ( A ) and quantifications of synapses (paired CtBP2-PSD95) per IHC in cochlear regions coding 16 KHz ( B ) and 32 KHz ( C ). The cochlear samples were imaged in the regions coding 16 KHz and 32 kHz from explants treated with either medium alone for 2 h + 48 h (Ctrl + 48 h), medium containing kainate for 2 h and then medium alone for 48 h (KA + 48 h), medium containing 0.5 mM kainate for 2 h + NT3 for 48 h (KA + NT3 48 h), or kainate for 2 h+ BDNF for 48 h (KA + BDNF 48 h). Scale bar: ( A ) = 15 µm. ( D – I ): Quantification of synapses (paired CtBP2-PSD95) per IHC in cochlear regions coding 16 KHz ( D , F , H , J ) and 32 KHz ( E , G , I , K ). In ( D , E ), the samples were collected from explants exposed to medium alone for 2 h + 48 h (Ctrl + 48 h); medium containing kainate for 2 h, then medium alone for 48 h (KA + 48 h); medium containing kainate for 2 h, then medium containing LM22A-4 at 1, 5, and 10 µM for 48 h (KA + LM22A-4 48 h). In ( F , G ), the samples were collected from explants exposed to medium alone for 2 h + 48 h (Ctrl + 48 h); medium containing kainate for 2 h, then medium alone for 48 h (KA + 48 h); medium containing kainate for 2 h, then medium containing CF3CN at 1, 5, and 10 µM for 48 h (KA + CF3CN 48 h). In ( H , I ), the samples were collected from explants exposed to medium alone for 2 h + 48 h (Ctrl + 48 h); medium containing kainate for 2 h, then medium alone for 48 h (KA + 48 h); medium containing kainate for 2 h, then medium containing R13 at 1, 5, and 10 µM for 48 h (KA + R13 48 h). ( J , K ): Comparison of the regenerative efficacy of BDNF, NT3, and different BDNF mimetics at their effective concentration in the 16 and 32 kHz coding regions. All data are expressed as mean ± SEM (n = 6–10 cochleae per condition). One-way ANOVA test was followed by Dunn’s test: * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001, **** p ≤ 0.0001.

Article Snippet: R13, a TrkB ligand prodrug, was purchased from Axon Medchem (#3775, Groningen, Netherlands).

Techniques: Labeling, Comparison, Concentration Assay