Figure 3. Endothelial-Specific Tlr4 Deletion with a Tie2-Cre Driver Protects against LPS-Induced Preterm Birth.

(A) DIG-in situ hybridization for Tlr4 in decidual endothelia of Tlr4^f/f and Pgr^Cre/+Tlr4^f/f mice on day 16 of pregnancy. Blue color indicates the Tlr4 signal. Dec, decidua. Arrow heads indicate blood vessels (Bv). Scale bar, 100 μm.

(B) PR (progesterone receptor)-positive cells are absent in the endothelium in days 4 (left) and 16 (right) uteri. Arrow head indicates blood vessel. Scale bars for the left and right panels represent 50 μm and 200 μm, respectively.

(C and D) The ratio of preterm birth (C) and dead pups (D) compared to total number of pups in Tlr4^f/f and Tie2^Cre/+Tlr4^f/f mice with or without a high dose of LPS (40 μg/mouse). n, number of dams examined.

(E) Parturition timing in Tlr4^f/f and Tie2^Cre/+Tlr4^f/f mice with or without LPS. n, number of dams examined.

(F) Dark-field and bright-field images of in situ hybridization for Cox2 in Tlr4^f/f and Tie2^Cre/+Tlr4^f/f deciduae after 1 h of LPS exposure (40 μg/mouse). Arrow heads indicate blood vessels. Scale bar, 500 μm.

(G) Dark-field and bright-field images of in situ hybridization for Il6 in Tlr4^f/f and Tie2^Cre/+Tlr4^f/f deciduae after 1 h of LPS exposure (40 μg/mouse). Arrow heads indicate blood vessels. Scale bar, 500 μm.

See also Figure S4.