SHH expression in placental tissues and trophoblast cell oxidative stress injury during preeclampsia

To assess the association between Sonic hedgehog (SHH) protein expression levels on placental tissues and the presence of preeclampsia and to assess oxidative stress in cultured trophoblast cells from placentas of women with preeclampsia treated under different conditions.

We enrolled 30 pregnant women with early-onset preeclampsia (<34 weeks), 30 with late-onset preeclampsia (≥34 weeks), and 60 healthy pregnant women with early or late gestational ages for two control groups. We used ELISA tests to measure individual serum SHH levels. Also, we used real-time PCR, and Western blotting to detect Shh transcript and protein levels in placental tissues, respectively, and immunohistochemistry to localize the protein in placental tissues. We isolated trophoblast cells from placentas and cultured them in vitro under different conditions to compare oxidative stress injury and apoptosis rates between them.

The mean serum SHH levels in early and late preeclampsia groups were similar (p>0.05). Placentas of women with and without preeclampsia both expressed SHH protein mainly in syncytiotrophoblast cytoplasms. The mean placental SHH protein expressions in both women with early-onset and late-onset preeclampsia were significantly higher than that in the women of the late gestational age control group (p<0.05). The mean Shh mRNA abundances in early-onset and late-onset preeclampsia placentas were significantly higher than that in the late gestational age control placentas (p<0.05). The placental mitochondria oxidative stress injury was significantly higher in the preeclampsia than in the control group (p<0.05). The oxidative stress injury and apoptosis of trophoblast cells were higher in preeclampsia groups than in the late gestational age control group (p<0.05). Trophoblast cells treated with SHH serum had significantly lower oxidative stress than the same cells grown in the presence of preeclamptic serum (p<0.05).

The expression of Shh in placental tissues is associated with the oxidative stress mechanism during preeclampsia.