Adrenaline induced disruption of endogenous melatoninergic system, antioxidant and inflammatory responses in the gastrointestinal tissues of male Wistar rat: an in vitro study

Abstract

The current study aimed to demonstrate the potentially adverse effects of adrenaline, an endogenous stressor, on the melatonergic system, oxidative status, antioxidative responses and inflammatory markers in different parts of gastrointestinal tract of Wistar rat. These included stomach, duodenum and colon and they were incubated with different concentrations (2.5, 5.0 and 10.0 µg/mL) of adrenaline for 1h, respectively. The levels of melatonin, gene expressions of arylalkylamine N-acetyltransferase (AANAT) and melatonin receptor 1 (MT1) as well as other stress-induced parameters including NF-kB expression, levels of cAMP, calcium, malondialdehyde, protein carbonyl content, reduced glutathione, nitrate, superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase, tumour necrosis factor-α, IL-1β, IL6 and IL10 were systemically measured in these tissues. An adrenaline dose-dependent decrease in level of melatonin, AANAT, MT1 and NF-kB in these tissues were observed. In contrast, the profound increases in the levels of cAMP, calcium and all oxidative stress markers, inflammatory cytokines (except IL10), and activities of antioxidant enzymes (except superoxide dismutase) were observed after adrenaline treatment. A maximum effect was found in tissues treated with 5 µg/mL of adrenaline. The Correlation studies between melatonin level and other parameters (any two at a time) indicated a potentially physiological interplay between adrenaline stress and melatonin tissue levels. Collectively, the results provided the novel data on the adverse effects of adrenaline on the endogenous melatonergic system, antioxidant and inflammatory responses in the gastrointestinal tissues of rats.

Amelioration of adrenaline induced oxidative gastrointestinal damages in rat by melatonin through SIRT1-NFκB and PGC1α-AMPKα cascades

“…Several animal studies have confirmed these similar observations (8,9,13,43,44). The PCO is a common marker of protein oxidative damage (8,9,45,46). The increased tissue levels of PCO indicate structural and functional damage of proteins linked to the auto-oxidation of adrenaline.…”

“…Increased levels of LPO in GI tissues might be a consequence of oxidative injury caused by high dose of adrenaline (42). Several animal studies have confirmed these similar observations (8,9,13,43,44). The PCO is a common marker of protein oxidative damage (8,9,45,46).…”

“…Levels of targeted proteins (Table 1) in the tissue homogenates and mitochondrial samples were evaluated by Western blot (9,25). In brief, 60 mg protein were loaded in each well and subjected to SDS-PAGE (12%) with the method of Laemmli (26).…”

“…Following wash (thrice), the blot was incubated with secondary antibody (Goat anti-rabbit IgG ALP conjugate; 1:3000 dilution) for 2 h at 4°C, washed thrice and then finally incubated in BCIP/NBT substrate. Band intensity of each immuno-blot was normalized by the intensity of β-actin (NIH, Bethesda, MD, USA) and quantified through densitometric analysis using ImageJ software and expressed in relative densitometric units (9). Details of antibodies are mentioned in Table- Tissue level of lipid peroxidation (LPO) was estimated in the form of TBARS (thiobarbituric acid reactive substances) (27).…”

Melatonin protects against cardiac damage induced by a combination of high fat diet and isoproterenol exacerbated oxidative stress in male Wistar rats

“…Melatonin plays a remarkable role in the synchronisation of circadian rhythm, regulation of seasonal reproduction and enhancement of immune function in vertebrates (3). It is also a potent and broad spectrum antioxidant (3)(4)(5). Melatonin executes its antioxidant activities by up-regulation of the antioxidant enzymes, down-regulation of the pro-oxidant enzymes and directly detoxification of the free radicals (6,7).…”