ABSTRACT
In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack.
Subject(s)
Encephalomyelitis, Venezuelan Equine/metabolism , Light , Melatonin/metabolism , Olfactory Bulb/radiation effects , Animals , Circadian Rhythm , Dose-Response Relationship, Radiation , Encephalomyelitis, Venezuelan Equine/physiopathology , Male , Mice , Olfactory Bulb/metabolism , Olfactory Bulb/physiopathologyABSTRACT
To determine whether treatment with dehydroepiandrosterone (DHEA) improves the efficiency of immunization against the Venezuelan Equine Encephalomyelitis (VEE) virus, mice were vaccinated with the TC-83 VEE virus. DHEA (10 mg/kg) was administered in a single dose, 4 hours before vaccination. IgM antibody titers were determined at days 7, 14 and 21 post-immunization. Treatment with DHEA increased antibody titers at day 14 after immunization. Mice were challenged with live VEE virus at day 21, and viral titers were plaque assayed in chicken embryo fibroblasts from days 2 to 5 post-infection. After the challenge, viremia decreased on day 2 and brain virus levels were reduced at day 4 in mice treated with DHEA. These results suggest that DHEA treatment could enhance the efficiency of immunization against VEE virus in mice.
Subject(s)
Adjuvants, Immunologic/pharmacology , Dehydroepiandrosterone/pharmacology , Encephalitis Virus, Venezuelan Equine/immunology , Encephalomyelitis, Venezuelan Equine/prevention & control , Immunization , Viral Vaccines/immunology , Animals , Antibodies, Viral/blood , Brain/virology , Drug Evaluation, Preclinical , Encephalitis Virus, Venezuelan Equine/isolation & purification , Encephalomyelitis, Venezuelan Equine/virology , Immunoglobulin M/blood , Lethal Dose 50 , Male , Mice , Viral Load , Viremia/prevention & controlABSTRACT
When mice infected with the Venezuelan equine encephalomyelitis (VEE) virus were exposed to 2500 lux with a 12 h light: 12 h dark photoperiod, the serum levels of melatonin (MLT) remained constantly elevated. In mice exposed to 400 lux low levels of serum MLT were detected during the day and high levels during the night. An increase in the survival rate of the infected mice from 6 to 13 days after virus inoculation was also observed. The significant increment in the concentration of serum MLT produced by the high intensity light could be responsible for the longer survival rate of mice infected with the VEE virus.
Subject(s)
Encephalomyelitis, Venezuelan Equine/blood , Light , Melatonin/blood , Animals , Circadian Rhythm , Dose-Response Relationship, Radiation , Male , Mice , Survival RateABSTRACT
In the present study, we have evaluated whether melatonin (MEL) modulates Mn-induced decrease in spontaneous motor activity (SMA) and lipid peroxidation, estimated as malondialdehyde (MDA) formation, in several brain regions. In mice treated with manganese a decrease in SMA after 2 weeks of treatment was observed. In the group treated with Mn+MEL a significant greater reduction in SMA was detected at 4 weeks. MDA levels were reduced in both MEL and Mn treated mice. In the animals treated with MEL + Mn a higher reduction in MDA levels was observed. These results suggest that MEL modulates the effect of Mn on SMA and brain lipid peroxidation.
