Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB238

Poster Communications

Salt overload during gestation increases oxidative stress and impairs fetal survival ability in Sprague Dawley rats

O. M. Olumide1, I. I. Olatunji-Bello1

1. Department of Physiology, Lagos University College of Medicine, Ikeja, Lagos, Nigeria., Lagos, Nigeria.

The increase exposure to high salt diet in populations during gestation despite reported complication in studies has made it compelling for further studies on fetal survival. This study is therefore aimed at investigating the effects of high salt diet at varying stages of gestation. Fifty six female rats (150-200g) with regular estrus cycle were fed either normal diet of 0.3% sodium chloride (Nacl) or a high salt diet (HSD) of 8% Nacl for 6 weeks. Female rats were housed with male at ratio 2:1 on the evening of proestrus phase. The presence of spermatozoa in the vaginal smear of the rats the next day indicated Day 1 of pregnancy. The pregnant rats were selected for the study and were distributed into 2 groups (n=20) of control (0.3% Nacl) and HSD (8% Nacl) and were fed the diet throughout gestation. On days 8, 12 and 19 of pregnancy, caudal blood pressure (BP) was measured; serum and urine electrolytes (Na+, Cl-, K+) were determined using SFRI ISE 6000 electrolyte analyzer. Serum progesterone and estrogen were also measured using an Enzyme-linked Immuno Assay (ELISA) kit. Implantation sites (IS) were counted on day 8 while fetal number and placenta weights were recorded on days 12 and 19. Liter numbers and birth weight were also documented. Malondialdehyde (MDA) and the activities of the antioxidants enzymes; catalase (CAT), glutathione reductase (GSH) and superoxide dismutase were measured in both serum and placenta homogenate. Rats were anaesthetized with chloroform and sacrificed following cervical dislocation. Values are represented as ±SEM and compared with ANOVA. Mean arterial BP (100.90±2.55 mmHg vs. 89.41±1.94 mmHg), serum Na+ (146.2±5.43 mmol/L vs. 133.3±2.80 mmol/L) and Cl- (117.20±2.14 mmol/L vs 96.55±4.31 mmol/L) were significantly increased in the HSD when compared with control. Serum estrogen and progesterone was lower (p<0.05) in HSD (16.60±1.04pg/ml vs 20.13±0.61 pg/ml; 38.17±2.75ng/ml vs 49.13±2.46ng/ml) than control. Urine Na+ in HSD was higher (p<0.05) on day 8 (60.83±2.481mmol/L vs 51.25±5.11mmol/L) than control. IS was reduced (11.00±1.16 vs 14.00±0.78, p<0.05) and fetal number was reduced (p<0.05) on day 12(9.33±1.022 vs 12.83±0.75) and 19 (6.50±0.89 vs 9.67±0.49) in the HSD when compared with control. In the serum and placenta homogenate, CAT (2.61±0.53 mg/ml vs5.30±0.58mg/ml; 3.64±0.69mg/ml vs6.61±0.72mg/ml), GSH (2.62±0.39µmol/mlvs4.54±0.41µmol/ml;3.24±0.51µmol/ml vs5.36±0.47µmol/ml) and SOD (2.92±0.08mg/ml 6.72±0.073mg/ml;2.35±0.33mg/ml vs6.64±0.93mg/ml) were lower (p<0.05) while MDA (0.82±0.04nmol/ml vs0.44±0.01nmol/ml; 1.03±0.27nmol/ml vs0.26±0.09) was higher (p<0.05) in HSD than the control. In conclusion, high salt intake during pregnancy increases oxidative stress which affects fetal survival in rats.

Where applicable, experiments conform with Society ethical requirements