, Results are normalized to Gapdh, and are shown as ratios to the nonoperated (naive) value of WT mice. Values show the mean 6 S.E.M. *p < .05, **p < .005; unpaired Student's t-test. (b-j) Expression of SiglecH protein in the ipsilateral dorsal horn 3 days after L4 nerve injury. Immunoreactivity for Siglec-H (b,e,h, green) and Iba1 (c,f,i, red), and the merged images (d,g,j) of WT (b-g) and Siglech dtr/dtr (h-j) mice are shown, FIG URE 7 Siglec-H suppresses pro-inflammatory responses of microglia in a mouse neuropathic pain model. (a)

, Scale bar: 200 mm (b-d), 10 mm (e-j). (k) Expression of mRNA encoding proinflammatory cytokines (TNF-a and IL-1b) but not anti-inflammatory cytokines (IL-10 and TGF-b1) was upregulated in the ipsilateral dorsal horn of Siglech dtr/dtr mice. Ipsilateral L4 dorsal horn was obtained from WT and Siglech dtr/dtr mice at each time point after L4 nerve transection (n 5 3 for each time point), and mRNA expression was analyzed by qPCR. Results are normalized to Gapdh, and are shown as ratios to the nonoperated (naive) value of WT mice. Values show the mean 6 S.E.M. *p < .05, **p < 5.0 3 10 24 ; unpaired Student's t-test. (l-n) Microglial numbers in lamina I/IIo were unchanged between WT and Siglech dtr/dtr mice 7 days after injury. Merged images of Iba1 (green) and PKCg (red) immunostaining of WT (l) and Siglech dtr/dtr (m) mice are shown. The lamina I/IIo is surrounded by dotted lines. Scale bar: 200 mm. Microglial numbers in lamina I/IIo of contralateral (contra) and ipsilateral (ipsi) L4 dorsal horn were counted at 7d (n) (n 5 4; four images per animal). (o,p) Nerve injury-induced mechanical allodynia is exacerbated in Siglech dtr/dtr mice. The PWT of the contralateral (o) and ipsilateral (p) side was measured in WT and, Siglec-H expression in microglia. Note that faint signals for Siglec-H are predominantly observed in the endoplasmic reticulum/Golgi apparatus of microglia in Siglech dtr/dtr mice (arrows in h-j, high mag.)

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