Objective: To investigate the expression of interleukin-37 (IL-37) in placenta tissue and its relationship with the pathogenesis of severe preeclampsia.
Methods: All the patients were recruited in Qilu Hospital of Shangdong University from November 2012 to November 2013. Among them, thirty patients with severe preeclampsia were assigned to the preeclampsia group, and thirty-one healthy pregnant women were assigned to the control group. Immunohistochemistry of SP was used to detect the IL-37 protein expression in placenta tissue of the two groups. The expression level of IL-37 in placenta tissue of the two groups was detected by western blot. Besides, reverse transcription (RT)-PCR was used to detect the expression of IL-37 mRNA. The correlation between the expression of IL-37 mRNA and the delivery gestational age, body mass index (BMI) was analyzed.
Results: (1) IL-37 were detected in the placenta of both the preeclampsia group and the control group, and the expression site mainly located in the syncytiotrophoblast, with a small amount in cytotrophoblast. (2) The expression levels of IL-37 protein in the preeclampsia group and the control group were 0.59 ± 0.39 and 0.88 ± 0.22, respectively. The IL-37 mRNA levels in the preeclampsia group and the control group were 0.55 ± 0.17 and 1.11 ± 0.21, respectively. Both decreased significantly when compared to the control group (P < 0.05). (3) Significant correlation between the expression of IL-37 mRNA and the delivery gestational weeks (r = 0.209, P > 0.05) was seen neither in the preeclampsia group nor in the control group (r = -0.053, P > 0.05). In the severe preeclampsia group, the pregnant women's BMI had no significant correlation with IL-37 mRNA expression of placenta tissue (r = 0.102, P > 0.05), neither did the control group(r = -0.115, P > 0.05).
Conclusion: IL-37 expression is significantly lower in severe preeclampsia placenta tissue than that in the normal pregnant women, which may play a protective role in the course of severe preeclampsia.