Honokiol inhibits inflammation and endoplasmic reticulum stress in a rat model of pregnancy-induced hypertension

Abstract

The levels of inflammatory factors in pregnancy-induced hypertension (PIH) are closely correlated with the severity of the disease. The enhanced endoplasmic reticulum (ER) stress response and upregulated iNOS might contribute to the pathophysiology of preeclampsia. Honokiol has been shown to be a potential anti-inflammatory and anti-ER stress agent. However, the effect of honokiol on the inflammation and ER stress has not been investigated in a gestational hypertensive model. The present study aimed to elucidate the role of honokiol in inflammation, ER stress and endothelial/inducible nitric oxide synthase (eNOS/iNOS) in a PIH rat model. Rats with hypoxia-induced PIH were administered honokiol (0, 200, 600, 2000 lg/kg) daily for one week to different groups by intragastric administration. Systolic blood pressure (SBP) and urinary protein concentration were measured via the tail-cuff method and CBB kit. Proinflammatory cytokines and ER-stress markers, VEGF, NO, iNOS and eNOS in the plasma or placental tissue were analyzed by enzyme-linked immunosorbent assay (ELISA), quantitative real time polymerase chain reaction (RT-qPCR), NO assay kit or western blot. The blood pressure and urinary protein level in PIH rats were significantly decreased after honokiol. Honokiol significantly inhibited the elevated levels of proinflammatory cytokines and ER-stress markers, which were accompanied by the upregulation of eNOS, NO and VEGF mRNA in PIH rats. However, the level of iNOS was reduced by honokiol. Our study suggests a beneficial potential of honokiol in PIH rats through inhibition of proinflammatory cytokines and ER stress. Honokiol could be an intriguing therapeutic approach in ER stress related PIH.