Protective Effects of Calcitriol against Fructose-induced Hyperglycaemia and Dyslipidaemia in male Albino Wistar rats

Abstract

Background: Hyperglycemia and lipidaemia have been found to produced adverse metabolic alterations in glucose and lipid metabolism. The current study was designed to investigate the preventive role of calcitriol supplementation on fructose-induced hyperglycaemia and dyslipidaemia in fructose-drinking Albino Wistar rats. Methods:Twenty five (25) male Albino rats were used in this research work. The rats were divided into 5 groups of 5 animals each. Group I: Control; received normal rat feed + distilled water, Group II: Received normal rat feed + 125 μg/kg of Calcitriol (CTR), Group III: Received normal rat feed + 10% fructose solution (FDR), Group IV: Received normal rat feed + 10% fructose solution (FDR) + 0.3 mg/kg of glibenclamide (GLIB). Group V: Received normal rat feed + 10% fructose solution (FDR) + 125 μg/kg of Calcitriol (CTR). For the induction of hyperglycaemia and lipidaemia rats were given 10% fructose solution as drinking water for eight (8) weeks. The levels of fasting sugar and HbA1c were measured. Changes in body weights and lipid profile of rats were determined. Results: CTR group exhibited no significant (P ˂ 0.05) change in plasma glucose levels, HbA1c and body weights when compared to the control (5.09 ± 0.45 vs 5.20 ± 0.15 mmol/L and 4.57 ± 0.24 vs 4.29 ± 0.31 %, 193.0 ± 12.25 vs 189.2 ± 6.37 g). In FDR group fasting sugar levels, glycated haemoglobin (HbA1c) and weights were found to be significantly (P ˂ 0.05) increased compared group I (6.49 ± 0.16 vs 5.20 ± 0.15 mmol/L and 5.23 ± 0.17 vs 4.29 ± 0.31 %, 219.1 ± 17.36 vs 189.2 ± 6.37 g) respectively. Glibenclamide administration in GLIB + FDR group effectively abolished the fructose-induced hyperglycaemia and glycated haemoglobin in rats when compared to FDR group (5.53 ± 1.92 vs 6.49 ± 0.28 mmol/L and 4.10 ± 0.54 vs 5.23 ± 0.17 %). In FDR + CTR group calcitriol supplementation successfully blocked and prevented the fructose-induced increased in fasting sugar, HbA1c levels and weight in rats when compared with FDR group (5.12 ± 0.39 vs 6.49 ± 0.28 mmol/L, 4.43 ± 0.24 vs 5.23 ± 0.17 % and 192.2 ± 11.23 vs 219.1 ± 17.36 g) respectively. CTR group exhibited no significant (P ˃ 0.05) changes in lipid profile parameters compared control (3.88 ± 0.19 vs 3.89 ± 0.38 mmol/L, 1.20 ± 0.16 vs 1.12 ± 0.11mmol/L, 2.16 ± 0.17 vs 2.20 ± 0.22 mmol/L and 1.32 ± 0.22 vs 1.30 ± 0.16 mmol/L) for total cholesterol, triglyceride, LDL and HDL respectively. FDR exhibited a significant (P ˂ 0.01) increase in serum total cholesterol (4.90 ± 0.23 mmol/ L) when compared to control group (3.88 ± 0.19 mmol/L) Similarly, fructose feeding resulted in a significant elevation (P ˂ 0.01) in triglycerides levels (1.90 ± 0.27 vs 1.20 ± 0.16 mmol/L) in comparison to the corresponding control rats. In addition, FDR group rats had elevated levels of LDL-C which was significant (P ˂ 0.05) when compared with the corresponding control group (2.80 ± 0.26 vs 2.16 ± 0.17 mmol/L). Although, high density lipoprotein cholesterol was increased in FDR group, the increased was not significant (P ˃ 0.05) and the result was comparable to that of the control (1.22 ± 0.07 vs 1.32 ± 0.22 mmol/L). In FDR + CTR group, oral calcitriol supplementation potentially prevented fructose in inducing alterations in serum lipid profiles when compared to FDR group. Conclusion: The result showed that calcitriol supplemention infructose-drinking rats protects against hyperglycaemia and dyslipidaemia.