Abstract. In Saudi Arabia, the consumption of carbonated
soft drinks is common and often occurs with each meal.
Carbonated soft drink consumption has been shown to
exhibit effects on the liver, kidney and bone. However, the
effects of these soft drinks on brain activity have not been
widely examined, particularly at the gene level. Therefore,
the current study was conducted with the aim of evaluating
the effects of chronic carbonated soft drink consumption
on oxidative stress, brain gene biomarkers associated with
aggression and brain histology. In total, 40 male Wistar rats
were divided into four groups: Group 1 served as a control
and was provided access to food and water ad libitum; and
groups 2‑4 were given free access to food and carbonated
soft drinks only (Cola for group 2, Pepsi for group 3 and
7‑UP for group 4). Animals were maintained on these diets
for 3 consecutive months. Upon completion of the experimental
period, animals were sacrificed and serological and
histopathological analyses were performed on blood and
tissues samples. Reverse transcription‑polymerase chain
reaction was used to analyze alterations in gene expression
levels. Results revealed that carbonated soft drinks increased
the serum levels of malondialdehyde (MDA). Carbonated
soft drinks were also observed to downregulate the expression
of antioxidants glutathione reductase (GR), catalase and
glutathione peroxidase (GPx) in the brain when compared
with that in the control rats. Rats administered carbonated
soft drinks also exhibited decreased monoamine oxidase
A (MAO‑A) and acetylcholine esterase (AChE) serum and
mRNA levels in the brain. In addition, soft drink consumption
upregulated mRNA expression of dopamine D2 receptor
(DD2R), while 5‑hydroxytryptamine transporter (5‑HTT)
expression was decreased. However, following histological
examination, all rats had a normal brain structure. The
results of this study demonstrated that that carbonated soft
drinks induced oxidative stress and altered the expression of
certain genes that are associated with the brain activity and
thus should be consumed with caution. |
