Fig. 1

The expression of TREM2 in microglia is upregulated in the ipsilateral SDH after SNI surgery. a The 50% PWT in the ipsilateral (Ipsi) and/or contralateral (Contra) hind paw was evaluated by von Frey test before and after SNI in Sham or SNI rats. Data were presented as the mean ± SEM. *p < 0.05, ***p < 0.001 vs. SNI-Contra group. b Representative blots and expression of TREM2 was analyzed by Western blot in the ipsilateral (Ipsi) and/or contralateral (Contra) SDH at post-operative day 0-14 following spared nerve injury (SNI) (n = 6/group). c The expression of TREM2 mRNA was detected by qPCR in the SDH at different time points following SNI. Results were normalized to the housekeeping gene Gapdh (n = 6/group). **p < 0.01, ***p < 0.001 vs. Ipsi, &&p < 0.01, &&&p < 0.001 vs Contra. d Representative confocal images of double immunostaining showing colocalization of Iba-1 (green) and TREM2 (red) signals in the SDH at 7 days in Sham and SNI rats. The yellow dotted boxes showed areas of higher magnification in the ipsilateral SDH (a’ and b’). Original magnification, ×20. Scale bar, 200 μm (d), 50 μm (a’ and b’; d). e, f Quantification of TREM2 fluorescence intensity (e) and Iba1-positive microglial numbers (f) in the ipsilateral SDH at all time points in Sham and SNI rats (n = 4 per group). All results were presented as the mean ± SEM. **p < 0.01, ***p < 0.001 vs. SNI. &&p < 0.01, &&&p < 0.001 vs Sham