Figure 7. mTreg expand during gestation to promote pregnancy induced analgesia.

(A) Schematic representation of experimental assessment of pregnancy-induced analgesia (PIA) in mice. 4 weeks after SNI, female mice were mated with a syngeneic male. (B) Nociceptive thresholds of pregnant SNI mice before and after delivery, compared to unmated nulliparous mice, n=8–12 per group. (C) Area under the curve (AUC) of nociceptive threshold curves of pregnant mice injected IT with δOR-selective antagonist naltrindole (pink) or vehicle (white). (D) PIA in mice lacking δOR on MrgprD⁺ sensory neurons or controls, n= 4–5 per group. (E) PIA comparing WT or Rag2^−/− mice, n=13–19. (F) AUC of PIA of Rag2^−/− mice injected intrathecally with δOR-selective agonist, deltorphin 2, or vehicle during the first 2 trimesters of gestation. (G-J) Representative flow cytometric plots of Tregs and Penk⁺ Tregs in pregnant (pink) compared to nulliparous (white) Penk^CreRosa26^tdTomato mice with SNI. Mice were harvested on the 12th day of gestation. (K) WT (white) or Foxp3-DTR (pink) mice injected with pegDT IT every 4 days demonstrating mTreg dependent PIA. (L) AUC of the PIA as represented in L. ns = not significant, *p<0.05, **p<0.01,***p<0.001. Related to Figure S6.