Bioflavonoids as agents for correcting nitro-oxidative stress and salivary gland functions in rats exposed to alcohol during modeled lipopolysaccharide-induced systemic inflammatory response

Abstract

The aim: To investigate the effects of bioflavonoids (curcumin, epigallocatechin-3-gallate and quercetin) on nitro-oxidative stress and the functions of submandibular SGs in rats under alcohol exposure during SIR. Materials and methods: The studies were conducted on 35 rats of the Wistar line weighing 205-220 g, divided into 5 groups of seven animals in each: the 1st group, control group I, included animals receiving isotonic sodium chloride solution intragastrically twice a day; the 2nd group, control group II, included rats exposed to alcohol (in a dose of 24 mg/kg intragastrically through gavage a twice a day) for last 2 weeks during lipopolysaccharide (LPS)-induced SIR; the rats of the 3rd, 4th and 5th groups exposed to alcohol during LPS-induced SIR, which also received bioflavonoids. The bioflavonoids (“Sigma-Aldrich, Inc.”, USA) were as following: curcumin (in a daily dose of 200 mg/kg), epigallocatechin-3-gallate (in a daily dose of 40 mg/kg), and quercetin (in a daily dose of 200 mg/kg), respectively. SIR was induced by intraperitoneal administration of Salmonella typhi LPS (during the first week a dose of 0.4 µg/kg of body weight was administered 3 times a week; during the next 7 weeks of the experiment rats received 0.4 µg/kg of body weight once a week. The formation of superoxide anion radical (О2), activity of NO-synthase – total (NOS), its constitutive and inducible isoforms (cNOS, iNOS), and concentration of peroxynitrites and S-nitrosothiols were evaluated spectrophotometrically. To assess the functional status of submandibular SGs in their homogenate we determined α-amylase activity (spectrophotometrically) and the aquaporin-5 concentration (by enzyme-linked immunosorbent assay). through gav-agewithorogastriccannul. Results: When applying bioflavonoids under the conditions of alcohol administration during SIR, NADH-induced .О2 production decreased and yielded to the result in the control group II by 36.8% under administering curcumin, by 34.5% under administering epigallocatechin-3-gallate, and by 41.3% under administering quercetin. The total NOS activity in SGs tissues was inferior by 42.8% to the relevant data in the control group II (under curcumin administration), by 33.7% (under epigallocatechin-3-gallate administration) and by 46.6% (under quercetin administration); and the iNOS activity decreased by 47.0, 38.3 and 52.0%, respectively. Under the administration of bioflavonoids peroxynitrites concentration in the submandibular SGs tissues was inferior to the control group II by 35.6% (under curcumin administration), by 37.4% (under epigallocatechin-3-gallate administration), and by 39.3% (under quercetin administration); the content of S-nitrosothiols was lower by 34.5, 31.1 and 35.3%, respectively. The administration of bioflavonoids led to the changes in α-amylase activity in the submandibular SGs tissues: its values exceeded the relevant data in the control group II by 40.4% (under curcumin administration), by 38.2% (under epigallocatechin-3-gallate administration), and by 34.1% (under quercetin administration); under those conditions aquaporin-5 concentration grew in 2.66, 2.61 and 2.55 times, respectively. Conclusions: The use of bioflavonoids (curcumin, epigallocatechin-3-gallate, and quercetin) under the combined administration of 40% ethanol solution and LPS considerably limits the development of nitro-oxidative stress in the tissues of the submandibular SGs. The administration of the bioflavonoids increases the level of cNOS coupling, and improves the functional status of the submandibular SGs under the combined administration of alcohol and LPS enhancing the activity of α-amylase and concentration of aquaporin-5.