Animal models
All animal procedures were carried out in accordance with the guidelines for the use of laboratory animals published by the People’s Republic of China Ministry of Health (January 25, 1998) with the approval of the Ethical Committee of Experimental Animals of Second Military Medical University as well as Ethical Committee of Experimental Animals of Central South University.
Adult Sprague-Dawley rats (weight 200-220g) were obtained from Shanghai SLAC Laboratory Animal Co (Shanghai, China). The rats were housed in specific pathogen free animal house, and in social groups of 3–5 in a cage with regular light-dark cycles (lights on at 7:.m., lights off at 7:00p.m.) under controlled temperature (22±) and humidity (50±10%), and were given standard diet and water ad libitum. Breeding females were handled daily for 1 week. The female was placed with a male at 3:00p.m. The male was removed the following day at 8:00a.m. to its social group, and the female was transferred to a new cage. Pregnant rats with confirmation by microscopic analysis of vaginal smears for the presence of sperm. In the following experiments, a random number table method was used to assign animals. In the first experiment, pregnant rats were administered (s.c) with CBX (Sigma-Adrich, St.Louis, MO) at 0.6mg/kg,1.2mg/kg,2.4mg/kg or saline once every day from gestational day (GD) 7.5 to 17.5. In second experiment, pregnant rats were intravenously administrated with saline, CBX (0.6 mg/kg), CBX-loaded nanoparticles (CBX-NPs), CBX-NPs linked to scramble peptide (CBX-SCR), and CBX-NPs linked to chondroitin sulfate A (CSA) binding peptide (CBX-CSA) every two days from GD7.5 to GD 17.5. The dosage of CBX which was loaded in CBX-NPs, CBX-SCR and CBX-CSA was equivalent to 0.6 mg/kg. In the third experiment, pregnant rats were administered (s.c) with saline and dexamethasone (DEX,Sigma-Adrich) at the dosage of 0.1mg/kg once every day from GD7.5 to GD 17.5. The dosage of CBX and DEX were chosen based on the literature(Lindsay et al., 1996; Sanna et al., 2016) and our preliminary study. All the rats of above experiments were received measurement of blood pressure (BP) by the noninvasive tail-cuff system every two days from GD 7.5 to 19.5. On GD 20.5, the right carotid artery of the rats was catheterized for BP measurement under anaesthetization (urethane 800 mg/kg and alpha-chloralose 40 mg/kg, i.p.). Then, the animals were sacrificed by deep anesthetization, and maternal blood, pups, placentas, uterus and kidney tissues were collected. The above experiments were blinded to operators.