Quantification of reactive proliferation of neurod:GFP-positive progenitors. (A) Quantification of all PCNA-positive cells. Compared with the respective SAGs of unlesioned sides (ULS sham, ULS NaCl, ULS Ouabain), the number of PCNA-positive cells per section is increased following sham treatment, or NaCl or ouabain injections in the first 8 days post lesion (dpl). An even significant increase compared with the unlesioned side is present at 2 dpl following NaCl injection, at 4 dpl following ouabain injection and at 8 dpl following sham treatment, respectively. At 57 dpl, the proliferation rate in the lesioned SAG was significantly decreased to the levels of the unlesioned side. (B) Quantification of neurod:GFP/PCNA double-positive cells. Compared with the respective SAGs of unlesioned sides, the number of neurod:GFP-positive cells per section that re-enter the cell cycle is increased following sham treatment, or NaCl or ouabain injections. The peak of proliferation of active cycling neuronal progenitors is observed at 8 dpl with a significantly increased number of five to six neurod:GFP/PCNA double-positive cells per section in sham-treated and ouabain-injected SAGs. The number of proliferating neurod:GFP neuronal progenitors is significantly lower in NaCl-injected SAGs compared with sham-treated and ouabain-injected SAGs at 8 dpl. However, changes in the overall proliferation rate in NaCl-injected SAGs follow a similar trend as seen in sham-treated and ouabain-injected SAGs. The number of neurod:GFP/PCNA double-positive cells per section has significantly decreased at 16 and 57 dpl in sham-treated and ouabain-injected SAGs, respectively, although a small number of lesioned animals still showed low numbers of neurod:GFP/PCNA double-positive cells in each lesion type. Notably, neurod:GFP/PCNA double-positive cells were infrequently also observed in the unlesioned side, in particular, in ouabain-injected animals, in which an average of 0.5–1 neurod:GFP/PCNA double-positive cells per section was seen. Samples size n = 3 (n = fish with three sections/SAG; exception: 4 dpl/NaCl: n = 2); data are presented as mean ± SEM. Two-way ANOVA with Tukey’s multiple comparisons test; ***p ≤ 0.001; **p ≤ 0.01; *p ≤ 0.05.
|
