Effects of Salmon Calcitonin and Omega - 3 Fatty Acids on Glucoregulatory Indices, Lipid Profile and Antioxidant Markers in Experimental Knee Osteoarthritis in Wistar Rats

Summary: It has been opined that a combined therapeutic approach should be considered in the optimal management of osteoarthritis (OA). Therefore, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids (N-3), relative to diclofenac sodium (DF) on selected biochemical parameters in induced osteoarthritic rats. Forty (40) adult male Wistar rats were used for this study. The rats were divided into 8 groups (n=5), viz: Group 1-Normal control; Group 2-OA control; Group 3-OA+N-3 (200 mg/kg, p.o.); Group 4-OA + low dose of Sct (Sct.Lw-2.5 IU/kg, i.m.); Group 5-OA + high dose of SCT (Sct.Hi-5.0 IU/kg, i.m.); Group 6-OA+N-3+Sct.Lw; Group 7-OA+N-3+Sct.Hi; and, Group 8-OA+DF (1 mg/kg, p.o.). Osteoarthritis was induced with 4 mg of sodium monoiodoacetate in 40 μl of saline. The solution was injected intra-articularly into the left knee joint space of anaesthetised (sodium pentobarbital - 40 mg/kg, i.p.) rats. Nine (9) days afterwards, treatments started, and they lasted for 28 days. The results showed that Sct has hypocalcaemic, hypocortisolism, and anti-dyslipidaemic effects. It significantly inhibited nitric oxide (NO) production and insulin release. Like Sct, N-3 have hypocortisolism and anti-dyslipidaemic actions. Nevertheless, they caused significant increases in hepatic glycogen content and plasma levels of calcium ion, insulin and NO. Although DF was also observed to stimulate insulin release and NO synthesis, it significantly increased plasma level of LDL-c, but significantly decreased HDL-C. In conclusion, N-3 annul the undesirable effect of Sct, presenting it as a better anti-arthritic drug. Moreover, the combined administration of both pharmacological agents proffer preferable therapeutic benefits in OA condition relative the single or DF therapy.

Keywords
Salmon calcitonin; Omega - 3 fatty acids; Osteoarthritis; Glucose homeostasis; Lipid profile; Antioxidant