Thyme (Thymus vulgaris) is an herbal plant with pleiotropic medicinal properties. In this
study, we examined the possible protective effect of an ethanolic extract of thyme
leaves against the renal oxidative stress induced by sodium nitrite (NaNO2). Male
Swiss mice received either saline or thyme extract for 15 days (0.5 g/kg body weight,
orally). NaNO2 (60 mg/kg) was injected intraperitoneally at Day 14. The protective
group received the thyme extract for 15 days and NaNO2 on Day 14. Blood and kidney
samples were taken from all groups to measure serum urea, blood urea nitrogen
(BUN), creatinine, serum, tissue antioxidant activity, and the inflammatory cytokines
IL-1β
and IL-6.
Quantitative real-time
PCR (qRT-PCR)
was used to examine the expression
of kidney injury marker-1
(Kim-1),
TNF-α,
nuclear factor erythroid-2
related factor
2 (Nrf2), and hemoxygenase-1
(HO-1),
all of which are associated with kidney redox
and oxidative stress. Pretreatment with thyme extract reduced the effects of NaNO2
on urea, BUN, and creatinine, and reversed its effect on tissue and serum antioxidants.
NaNO2-induced
nephritis as demonstrated by the upregulation in mRNA expression
of Kim-1
and TNF-α,
which was, however, recovered and protected by pretreatment
with thyme extract. Expression of Nrf2 and HO-1
was upregulated by treatment with
thyme extract and downregulated by NaNO2 intoxication. NaNO2-induced
congestion
in glomeruli and dilatation of the renal tubules, conditions that were restored in
the group pretreated with thyme extract. NaNO2 upregulated Bax immunoreactivity
and caused apoptosis in renal structures. Thus, thyme extract is effective in managing
the renal toxicity associated with oxidative stress and renal redox. |
