Deafferentation-Induced Redistribution of MMP-2, but Not of MMP-9, Depends on the Emergence of GAP-43 Positive Axons in the Adult Rat Cochlear Nucleus

Figure 4

GAP-43 expression in AVCN after complete or incomplete VNTB lesion and subsequent cochlear ablation. (a) Little GAP-43 expression was found in AVCN of control animals. Inset: no staining occurred when omitting the primary antibody. (b, c) Following cochlear ablation, GAP-43 staining emerged around POD3 (b) and reached maximal intensity by POD7 (c). (d, e) Combining complete lesion of VNTB with cochlear ablation (KAcL + CA) led to near-complete failure of GAP-43 expression in AVCN. (f) In cases with incomplete lesion (KAiL + CA) of VNTB, GAP-43 staining failed only locally, producing a patchy staining in AVCN. Frames indicate test fields for quantitative analysis of local GAP-43 staining density. Scale bar in (a)–(f), including inset in (a) 200 μm. Global contrast adjustments are identical for all photographs shown. (g) Staining intensity of GAP-43 immunoreactivity in the AVCN given as gray tone mean. Bars indicate ipsilateral-to-contralateral ratio (i/c) for cases with CA alone and KAcL + CA at POD3 and POD7 following cochlear ablation. Asterisks indicate significant differences among groups, number signs (hash symbols) indicate significant differences against control. (h) Heterogeneity of GAP-43 staining in ipsilateral AVCN after CA, KAcL + CA, and KAiL + CA. Bars indicate ratio between the strongest and faintest GAP-43-stained region within the AVCN.