EFFECT OF CO-ADMINISTRATION OF ACETAMINOPHEN AND METHIONINE ON MICRONUTRIENT METABOLISM

Abstract

Generally, altered micro-nutrient levels affect the anti-oxidant defense mechanism and impact significantly on genomic stability. Acetaminophen induces tissue damage, which is prevented by methionine. However, the influence of acetaminophen and methionine interaction on micro-nutrient levels is unknown. In this study, the possible acetaminophen and methionine-induced micro-nutrient alterations were investigated. One hundred and sixty female Wistar rats (270-350g) divided into 20 groups of eight rats each were administered with acetaminophen, and acetaminophen and methionine (p.o) for the acute and chronic studies. In the acute study, 350, 1000, 3000 and 5000 mg/kg body weight of acetaminophen were administered to groups 1-4 respectively, as well as 5-8. Similar doses of acetaminophen and methionine (5:1) were administered to groups 9-12 and 13-16 while normal saline was administered to group 17 (actute-control). In the study, groups 18 and 19 were administered daily with 350 mg/kg acetaminophen and acetaminophen and methionine respectively while group 20 (chronic-control) received normal saline and were sacrificed after 30 days. Groups 1-4 and 9-12 rats were sacrificed at 4 hours (peak of absorption) while those in groups 5-8 and 13-16 were sacrificed at 16 hours (peak of toxicity). Sera obtained from blood (8 mL) were analysed for Superoxide Dismutase (SOD), liver markers (alanine aminotransferase-ALT, aspartate aminotransferase-AST, alkaline phosphatase-ALP, gamma-glumly transferase, bilirubin, total protein, albumin) and renal function markers (urea, creatinine) by spectrophotometry. Micronutrients- Cu, Cr, Fe, Se, Zn were determined by atomic absorption spectrophotometry while high-performance liquid chromatography was used for the determination of vitamins (A, C, E) and folic acid. Hepatic and renal tissues were subjected to histological assessment. Data were analysed using Pearson's correlation coefficient, Student's t-test and analysis of variance. Level of significance at p=0.05. Acetaminophen and methionine-treated rats showed similar levels of hepatic and renal function markers as control in both acute and chronic studies. However, at 16 hours, acetaminophen-treated rats (1000 mg/kg) had respectively significantly higher levels of AST, ALT and urea (487.3±80.4 IU/L, 379.7±153.9 IU/L; 10.6±1.8 mmol/L) compared with acetaminophen and methionine-treated rats (33.8±12.1 IU/L, 3.40±0.7 nmol/L) and control (36.4±10.8 IU/L, 33.8±12.1 IU/L, 3.40±0.7 mmol/L). Renal histology revealed tubular necrosis (acetaminophen) and no visible lesion (control; acetaminophen and methionine). Comparison of micronutrients in acetaminophen and methionine treated rats between each of the doses and controls at 4 hours showed significant differences except Cu at 1000 and 5000 mg/kg (134.1±3.9 and 147.1±29.3 ug/dL), vs control (139.9±8.5 ug/dL). Fe at 3000 mg/kg control (133.2+21.6 vs 145.7±5.2 ug/dL); folic acid at 350 mg/kg vs control (8.4±1.3 vs 8.1± 0.1ng/mL) and vitamin E at 350mg/kg vs control (0.9±0.1 vs 0.9±0.1 mg/dL). At 16 hours, all micronutrients except Cr at 3000 (0.2±0.1, 0.2±0.1 ug/L) mg/kg had significant alterations. Significant reduction in activity of SOD was recorded at 1000, 3000 and 5000mg/kg (11.9±0.1, 11.3±0.1 10.8±0.1 Umg/protein) vs control (12.8±0.3 Umg/protein). Co.administration of acetaminophen and methionine induced alterations in micronutrient levels in nephroprotected rats. This may be attributed to increased free radical generation suggestive of oxidative stress. Supplementation with micronutrients may be necessary during acetaminophen and methionine drug administration.