The gene expression profile in SD rats showed a decrease in the expression of Tgfb1, Inha, and Fstl3. In contrast, WIS placenta responded to infection with an increase in Htra1, Tgfb1, and Fstl3. Moreover, while a decrease in Inha was also observed in WIS placenta, the decrease in expression relative to control was less than half of that observed in SD rats, indicating less inhibition of Inha in the WIS rat strain. Here, HTRA1 is linked to infection.