Beneficial Effects of Exogenous Melatonin in Acute Staphylococcus aureus and Escherichia coli Infection-Induced Inflammation and Associated Behavioral Response in Mice After Exposure to Short Photoperiod

Abstract

The administration of melatonin during acute bacterial infection was evaluated in this study. Mice pre-exposed to normal photoperiodic (NP), short photoperiodic (SP), and long photoperiodic (LP) day lengths were infected separately with live Staphylococcus aureus (5 × 10 cells/ml) or Escherichia coli (2.5 × 10 colony-forming units/ml) and treated with melatonin (10 mg/kg body weight). Behavioral studies were performed before bacterial infection and after melatonin administration. In mice pre-exposed to SP, exogenous melatonin administration resulted in better clearance of bacteria from blood and behavioral improvement. Reduced glutathione content and superoxide dismutase activities were increased, with concomitant decrease in lipid peroxidation content and catalase activities in the liver, brain, and spleen after exogenous melatonin administration. The overproduction of tumor necrosis factor-α, interferon-γ, and interleukin-6 during acute bacterial infection in mice exposed to different photoperiods was probably regulated by the administration of exogenous melatonin, by reducing neutrophil recruitment to spleen, expression of inducible nitric oxide synthase and cyclooxygenase-2 in hypothalamus, and C-reactive protein in the serum, and was also associated with improved behavioral response. Photoperiodic variations in inflammatory and oxidative stress markers might be correlated to serum melatonin and corticosterone levels. This study suggests that the administration of melatonin during SP exposure is protective in infection-induced inflammation than NP and LP exposure.

Melatonin attenuates detrimental effects of diabetes on the niche of mouse spermatogonial stem cells by maintaining Leydig cells

“…Group M mice served as melatonin-treated group. They were fed with normal mouse chow and treated with a daily single dose of melatonin (10 mg/kg/d) diluted in saline through gavage 65 – 67 . The disposal time points are shown in Fig.…”

Bacteriostatic Potential of Melatonin: Therapeutic Standing and Mechanistic Insights

“…Melatonin not only has antibacterial effect in vitro , but also plays a significant role in the clinical prevention and treatment of bacterial infections in vivo ( 61 ). The inhibitory effects of melatonin in vivo includes both on PGPB [e.g., S. aureus ( 56 ) and S. pneumoniae ( 127 )] and PGNB [e.g., E.coli ( 128 ), H. Pylori ( 129 ) and K. pneumonia ( 130 )]. For example, in many GNB-infected animal models (e.g., sepsis), melatonin has a favorable effect in improving survival rates, ameliorating tissue damage and reducing levels of pro-inflammation mediators (e.g., TNF-α and IFN-γ), and increasing levels of anti-inflammation mediators (e.g., IL-10) ( 131 , 132 ).…”

“…Also in mammals, several reports have demonstrated substantial effects of melatonin in protecting against or alleviating bacterial infections. In mice infected with S. aureus and E. coli , symptoms were strongly attenuated by melatonin ( 56 ). More impressive evidence has been obtained in septic mice treated with cecal ligation and puncture, in which the decisive effects of melatonin were related to inhibition of NO-mediated inflammation in connection with mitochondrial protection ( 57 – 59 ).…”

Potential utility of melatonin in deadly infectious diseases related to the overreaction of innate immune response and destructive inflammation: focus on COVID-19

“…Inflammation largely belongs to the innate immune response. Meanwhile, several studies have reported antiviral and antibacterial activities of melatonin in animals and in plants (50)(51)(52)(53). These reports are challenging with regard to the questions of whether and under which conditions melatonin enhances or suppresses the innate immunity in organisms.…”