• Nav1.8 sodium channels, encoded by SCN10A, are predominantly expressed in the sensory neurons located in the dorsal root ganglion (DRG) and play an important role in human pain. In animal models of chronic pain, Nav1.8 is also verified to be involved, suggesting that Nav1.8 may be a potential target for treatment of chronic pain.
• Gene editing strategy:  The exons 2-28 of mouse Scn10a gene that encode the whole molecule (ATG to STOP codon) were replaced by human counterparts in B-hSCN10A mice. The promoter, 5’UTR and 3’UTR region of the mouse gene are retained. The human SCN10A expression is driven by endogenous mouse Scn10a promoter, while mouse Scn10a gene transcription and translation will be disrupted.
• mRNA expression analysis: Human SCN10A mRNA was detectable only in homozygous B-hSCN10A mice but not in wild-type mice.
• Protein expression analysis: SCN10A protein was detectable in DRG and cerebellum from homozygous B-hSCN10A mice and wild-type C57BL/6 mice.
• Application: This product is used for the efficacy research and safety evaluation of analgesic drugs.

Gene targeting strategy for B-hSCN10A mice. The exons 2-28 of mouse Scn10a gene that encode the whole molecule (ATG to STOP codon) were replaced by human counterparts in B-hSCN10A mice. The promoter, 5’UTR and 3’UTR region of the mouse gene are retained. The human SCN10A expression is driven by endogenous mouse Scn10a promoter, while mouse Scn10a gene transcription and translation will be disrupted.

Strain specific analysis of SCN10A mRNA expression in wild-type C57BL/6JNifdc mice and homozygous B-hSCN10A mice by RT-PCR. Dorsal root ganglia (DRG) RNA were isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hSCN10A mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human SCN10A primers. Mouse Scn10a mRNA was detectable in wild-type C57BL/6JNifdc mice and homozygous B-hSCN10A mice. Human SCN10A mRNA was detectable only in homozygous B-hSCN10A mice but not in wild-type mice.

Western blot analysis of SCN10A protein expression in homozygous B-hSCN10A mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hSCN10A mice (H/H), and then analyzed by western blot with anti-hSCN10A antibody. 40 μg total proteins were loaded for western blotting analysis. SCN10A protein was detectable in DRG, brain, cerebellum and skin from homozygous B-hSCN10A mice and wild-type C57BL/6 mice.

CFA-induced inflammatory pain and analgesic effects of VX-548 in wild-type mice and B-hSCN10A mice. The mechanical pain thresholds in B-hSCN10A mice were similar to those in the wild-type mice. In wild-type mice and B-hSCN10A mice, CFA injection markedly reduced mechanical pain thresholds. In wild-type mice, VX-548 at 1 mpk didn’t alleviate CFA-induced inflammatory pain. In B-hSCN10A mice, VX-548 at 1 mpk significantly alleviated inflammatory pain with an analgesic effect lasting up to 2 h. B-hSCN10A mice provide a powerful preclinical model for in vivo evaluation of the efficacy of targeted human SCN10A analgesic drugs. (A) Grouping and Treatment. (B) The schematic diagram of CFA-induced inflammatory pain modeling. (C) Analgesic effect of VX-548. **P < 0.01, ***P < 0.001.