Figure 4. Nociceptor populations are reduced in Prdm12^AvilCKO mice.

(A) RNAscope using exon-V-specific probes confirmed knockout of Prdm12 from mutant DRGs. Scale bar, 50 μm.

(B) Prdm12^AvilCKO mice have a reduction of Tom⁺ neurons, p = 0.0326.

(C and D) The remaining neurons in Prdm12^AvilCKO are larger, on average (C) (p = 0.0466), because of selective loss of cells ≤ 300 μm² (D).

(E) Representative image showing number of IB4⁺ (arrows) and CGRP⁺ (arrowheads) nociceptors are reduced in Prdm12^AvilCKO DRGs. Scale bar, 100 μm.

(F and G) Quantification of IB4⁺ (F) (p < 0.0001) and CGRP⁺ (G) (p = 0.027) nociceptors as a percentage of the total Tom⁺ population of sensory neurons.

(H) Representative image of TRKA⁺ nociceptors and NF200⁺ myelinated neurons in Prdm12^AvilCKO and control mice. Scale bar, 100 μm.

(I) Quantification showing significant reduction of TRKA⁺ nociceptors, p = 0.0135.

(J) Quantification of NF200⁺ neurons showing a wide range in Prdm12^AvilCKO mice, but no significant change from control littermates, p = 0.278.

(K and L) Representative image (K) and quantification (L) of the reduction in number of TRPV1⁺ nociceptors, p = 0.0025. Scale bar, 100 μm.

(M) qRT-PCR results plotted showing —log(p) versus log₂ (fold change) reveal significant reductions in many nociceptive gene transcripts, including Prdm12, but a significant increase in Trpm3, and no change in touch and proprioceptive genes. The dotted line represents p = 0.05; points above it differ significantly between control and mutant mice. Each point represents the analysis of significance and fold change from average values of n = 3 biological replicates.

All analysis was completed using DRGs from lumbar levels 2 through 5. Each data point in (B), (C), (F), (G), (I), (J), and (L) represents the average count across three DRGs from control (n = 3) or Prdm12^AvilCKO (n = 4) mice taken after behavior analysis around 10 weeks of age. All quantification analyzed by two-tailed Student’s t test; results are presented as means ± SEM.