Crude Oil Exposure Affects Hepatic Function of Diabetic Wistar Rats Treated with Metformin and Allium sativum

Abstract

Residential and occupational crude oil exposure has been linked to hematotoxicity but its effects on hepatotoxicity, especially in diabetic state is an emerging area.  This research investigated the effect of 5% crude oil exposure on hepatic function of diabetic Wistar rats treated with metformin with a view to determine if and how exposure to crude oil impacted diabetes management. The diabetes was induced by intra-peritoneal injection of 65mg/kg streptozocin (STZ) dissolved in citrate buffer which was confirmed 48 h after the injection. Rats were grouped into six (6) groups of five (5) rats each; group 1 was the normal control, group two was diabetic positive control group, group three was diabetic group treated with 250 mg/kg b.w. metformin, group four was diabetic untreated group exposed to 5% crude oil, group five was diabetic group treated with 250mg/kg b.w. metformin exposed to 5% crude oil, group six was diabetic rats treated with 200mg/kg b.w. of Allium sativum (garlic) extract plus 250 mg/kg b.w. metformin, exposed to 5% crude oil. The Rats were subjected to treatment for four weeks. Diabetic control animals had high activity of ALT, rise in AST activity was found in diabetic rats treated with standard, diabetic positive control and diabetic animals exposed to crude oil. Rats that received both the extract of Allium sativum plus standard drug (metformin) had normal level of aspartate aminotransferase (AST) as was in normal control animals. There was no significant difference (p<0.05) in activity of alkaline phosphatase (ALP) in all groups compared with normal control except standard drug treated group. Diabetic control rats and diabetic rats exposed to crude oil without treatment had high plasma protein content compared with other groups.  The histological examination showed that normal control animals and animals treated with the aqueous extract of Allium sativum plus standard drug had normal features of hepatocytes; moderate hepatic necrosis in rats treated with standard drug but exposed to 5% crude oil; and normal hepatic features in diabetic animals treated with standard drug as well as diabetic positive control animals. Therefore, crude oil exposures affect liver function of diabetic animals under treatment with metformin by inducing inflammation and necrosis of hepatic tissue. Intake of Allium sativum would help protect and improve hepatic function of diabetic people living in environment with crude oil spillage/exposure.

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Keywords: Allium sativum, Crude Oil, Diabetes Mellitus, Liver, Metformin