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.