Rutin, a common dietary
flavonoid, exhibits remarkable pharmacological activities such as
antioxidant and anti-inflammatory functions. Metabolic stress in mammals during the transition period affects mammary gland health. The aim of this experiment was to evaluate the protective effect of
rutin supplementing against metabolic stress in the mammary glands of sheep during the transition period, particularly after parturition. Transition Hu sheep (2-3 years old with 62.90 ± 2.80 kg) were randomly divided into three groups, the control group was fed a diet without
rutin, while
rutin (50 and 100 mg/kg
body weight/day) was administered to the two treatment groups (-28 day to +28 day relative to parturition). Serum and blood samples were collected from jugular vein on days -14, -7, +1, +2, +7, +14, +21, +28 relative to parturition. Mammary tissue biopsy samples of four sheep from the treatment group were harvested on day +28 postpartum. Compared to that in the control group,
rutin supplementation resulted in lower β-hydroxybutyrate (BHBA) while increasing the concentrations of non-
esterified fatty acids (
NEFA) and
globulin after lactation. Furthermore,
rutin treatment led to lower
hydrogen peroxide (H2O2) and
malonaldehyde (MDA) levels, resulting in increased
catalase (CAT),
glutathione peroxidase (GSH-Px),
superoxide dismutase (SOD) and total
antioxidant potential (T-AOC). Compared to that in the control group,
rutin inhibits the
mRNA expression of inflammatory markers such as
tumor necrosis factor-α (TNF-α). In addition,
rutin markedly downregulated the ratio of phosphorylated NF-κB p65 (p-p65) to total NF-κB p65 (p65). Meanwhile,
rutin supplementation resulted in high
mRNA abundance of the nuclear factor erythroid 2-like 2 (NFE2L2, formerly NRF2) and its target gene,
heme oxygenase-1 (HO-1), which plays critical roles in maintaining the redox balance of the mammary gland. Furthermore,
rutin treatment lowered the levels of various downstream apoptotic markers, including Bax, caspase3 and caspase9, while upregulating anti-apoptotic Bcl-2
protein. These data indicate the positive effect of
rutin against
inflammation, oxidative stress status, and anti-apoptotic activity in the mammary gland. The mechanism underlying these responses merits further study.