Prenatal exposure of bonny light crude oil induces embryotoxicity, impaired cognitive functions and cortico-hippocampal neurodegeneration on fetal outcomes of pregnant sprague-dawley rats

Abstract

The low Sulfur level, heavy metals and easy production rate of Bonny Light Crude Oil (BLCO) makes it one of Nigeria’s most explored oil. This study investigated the memory impairments, embryotoxicity and cortico-hippocampal neurodegeneration induced by prenatal exposure to BLCO of pregnant Sprague-Dawley (S-D) rats. Twenty pregnant rats were divided into 4 groups (A-D) of 5 rats each. Group A received normal saline as placebo. Group B-D received oral doses of BLCO at 0.73 ml/kg, 2 ml/kg and 3.8 ml/kg on pregnancy day 8–12.5 respectively. The pregnant rats were allowed to litter and nurse their pups. At 6 weeks postnatal life, twelve (12) selected young rats (n = 12) were accessed for behavioral study (Y-maze) and then sacrificed for biochemical and histological analysis. The results showed spontaneous abortion, still births and significantly reduced number of live births in the high dose group of BLCO compared to control. Length of gestation was significantly increased in the high dose group when compared to the control. CAT levels reduced significantly with concomitant increase in 8-OHdG among BLCO treated groups compared to control. Spontaneous alteration and number of arm entries decreased in the BLCO groups in comparison to control. Histological observation showed reduced cellular size, chromatolysis and presence of extracellular senile plaques in the prefrontal cortex and mild histological changes in the hippocampus architecture in the BLCO treated groups compared to the control. BLCO is capable of inducing embryotoxicity, impair cognition and cortico-hippocampal neurodegeneration.

Keywords:

• Bonny light crude oil (BLCO)
• oxidative stress
• prefrontal cortex
• hippocampus
• fetal outcome

Acknowledgements

Mr Daniel of Histopathology Laboratory, Department of Morbid Anatomy, College of Medicine of the University of Lagos, Nigeria for the preparation of histology slides.

Ethics approval

The experimental procedures were conducted in accordance with the NIH guidelines for the care and use of laboratory animals in line with guidelines of the Department of Anatomy, College of Medicine of the University of Lagos and the Health Research and Ethical Committee of the College of Medicine, University of Lagos with protocol assigned No: CMUL/HREC/02/19/493.

Disclosure statement

The authors declare that there is no conflict of interests regarding the publication of this paper.