EFFECT OF CURCUMIN ON NITRIC OXIDE SYSTEM IN SKELETAL MUSCLES OF RATS EXPOSED TO EXPERIMENTAL METABOLIC SYNDROME UNDER ROUND-THE-CLOCK LIGHTING

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The aim of the study is to evaluate the effect of the polyphenol curcumin on the indicators of the nitric oxide system in the skeletal muscles of rats under experimental metabolic syndrome (MS) and 24-hour lighting exposure. The experiments were performed on 21 male white Wistar rats weighing 215-255 g. The animals were divided into 3 groups of 7 animals in each. The animals of the 1st group (control I) were kept on a standard vivarium diet under regular alternation of light / dark periods. The rats of the 2nd group were subjected to experimental diet-induced MS (a 2-month carbohydrate-lipid diet including 20% aqueous fructose solution for drinking and appropriate food) under the 24-hour lighting (control II). The rats of the 3rd group received curcumin intragastrically through a gavage in a dose of 200 mg/kg daily during the 24-hour lighting exposure. The activity of total NO-synthase (NOS), its constitutive and inducible isoforms (cNOS, iNOS), the peroxynitrite content in alkaline and alkaline earth metals were determined in the homogenate of femoral muscles. The administration of curcumin under the experimental conditions probably reduced the total NOS activity by 39.7% and iNOS activity by 44.6% in the femoral muscle homogenate compared to the respective values of control II. Under these conditions, cNOS activity increased in 3.42 times, and its coupling index increased in 5.8 times compared to control II. The peroxynitrite concentration of alkaline and alkaline earth metals decreased by 25.1%. We can suggest that the administration of curcumin to rats under the experimental metabolic syndrome and the round-the-clock lighting exposure significantly affects the indicators of the nitric oxide system in the tissue of the femoral muscles, and in particular, it removes the imbalance of cNOS / iNOS activity, and improves the cNOS coupling that is accompanied by reducing the concentration of highly toxic active forms of nitrogen – peroxynitrites.