Figure 7.
Comparison of the maternal serum cytokine responses after immune challenge in middle and late gestation. The maternal administration of PolyI:C (5 mg/kg, i.v.) led to a marked increase in the serum protein levels of IL-1β, IL-6, IL-10, and TNF-α in both gestation day conditions relative to vehicle (saline) treatment, and these effects were generally more pronounced at 3 h after treatment (a) compared with the later sampling time at 6 h after treatment (b). However, whereas the PolyI:C-induced IL-10 and TNF-α responses were stronger in GD9 compared with GD17 dams at the earlier sampling interval, higher serum protein levels of IL-6 and IL-10 were detected in PolyI:C-exposed GD17 dams compared with the PolyI:C-treated GD9 group at 6 h after treatment. The number of pregnant dams in each group was 4, except in the following three groups: GD9-PolyI:C/3 h, n = 6; GD17-PolyI:C/3 h, n = 5; GD17-PolyI:C/6 h, n = 5. The levels of IL-1β in vehicle-treated animals were always below the detection limit (ND), regardless of the gestation day condition, and so were the IL-6 levels in the vehicle-treated GD17 group at both sampling intervals. All values are mean ± SEM. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001, statistical significance based on Fisher's LSD post hoc comparisons between the effects of PolyI:C treatment on GD9 (GD9-PolyI:C vs GD9-saline) and on GD17 (GD17-PolyI:C vs GD17-saline), as well as between the efficacy of PolyI:C treatment at the two treatment days (GD9-PolyI:C vs GD17-PolyI:C) at each sampling interval (3 or 6 h after treatment).
