Spleen morphology and hematological changes in rats following withdrawal of Nigerian Qua Iboe Brent crude oil

Possible amelioration of splenic damage and hematological changes in Nigerian Qua Iboe Brent crude oil-exposed rats following its withdrawal was investigated. A total of 56 male albino rats weighing between 200–250 g were used for this study. The rats received oral administration of 165 mg/kg body weight (low-dose), 330 mg/kg body weight (medium-dose) and 660 mg/kg body weight (high-dose) of Nigerian Quo Iboe Brent crude oil every 48 h for 28 days. Later, the crude oil was withdrawn from some rats for a period of 8 weeks. Hematological parameters and spleen morphology of rats that received crude oil and the rats from which the crude oil was withdrawn were compared with the controls that did not receive crude oil treatment. Administration of Nigerian Qua Iboe Brent crude oil significantly (p < 0.05) reduced the PCV levels in low-dose, low-dose crude oil-withdrawn, medium-dose crude oil-withdrawn, high-dose, and high-dose crude oil-withdrawn groups of rats. The EC was also reduced significantly (p < 0.05) in the medium- and high-dose groups of rats. In the same manner, TWBC was significantly (p < 0.05) reduced in the medium-dose crude oil-withdrawn, high-dose, and high-dose crude oil-withdrawn rats. It was only at low-dose level, after 8 weeks of crude oil withdrawal that there was a reduction in splenic weight. Splenic section (histopathology) of rats exposed to different doses of crude oil over 28-day period showed reticuloendothelial hyperpasia of the red pulp and variable degree of haemosiderin deposits. These changes were not completely ameliorated after 8 weeks of crude oil withdrawal. This study has shown that withdrawal of Nigerian Qua Iboe Brent crude oil from exposed rats did not reverse the splenic damage and the haematologic changes associated with this environmental pollutant.