The Effects of Resveratrol and Apigenin on Jejunal Oxidative Injury in Ducks and on Immortalized Duck Intestinal Epithelial Cells Exposed to H2O2.

Oxidative stress increases the apoptosis of intestinal epithelial cells and impairs intestinal epithelial cell renewal, which further promotes intestinal barrier dysfunction and even death. Extensive evidence supports that resveratrol and apigenin have antioxidant, anti-inflammatory, and antiproliferative properties. Here, we investigated the ability of these two compounds to alleviate diquat-induced jejunal oxidative stress and morphological injury, using the duck as a model, as well as the effects of apigenin on oxidative stress induced by H2O2 in immortalized duck intestinal epithelial cells (IDECs). Ducks were randomly assigned to the following four groups, with five replicates: a control (CON) group, a diquat-challenged (DIQ) group, a resveratrol (500 mg/kg) + diquat (RES) group, and an apigenin (500 mg/kg) + diquat (API) group. We found that serum catalase (CAT) activity and total antioxidant capacity (T-AOC) markedly reduced in the RES and API groups as compared to the DIQ group (p < 0.05); moreover, serum S superoxide dismutase (SOD) levels increased significantly in the API group as compared to the DIQ group (p < 0.05). In jejunal mucosa, the malondialdehyde (MDA) content in the RES and API groups decreased more than that in the DIQ group (p < 0.05). In addition, the jejunal expression levels of the NRF2 and GCLM genes in the RES and API groups increased notably compared with those in the DIQ group (p < 0.05); meanwhile, CAT activity in the RES and API groups was markedly elevated compared with that in the CON group (p < 0.05). In IDECs, apigenin significantly restrained the H2O2-mediated increase in MDA content and decrease in CAT levels (p < 0.05). Furthermore, apigenin increased the protein expression of p-NRF2, NRF2, p-AKT, and p-P38; downregulated that of cleaved caspase-3 and cleaved caspase-9; and reduced the ratio of Bax/Bcl-2 in H2O2-treated IDECs (p < 0.05). In conclusion, resveratrol and apigenin can be used as natural feed additives to protect against jejunal oxidative stress in ducks.

Effect of resveratrol treatment on apoptosis and apoptotic pathways during boar semen freezing.

Resveratrol (3,5,4'-trihydroxystilbene, RSV) has been widely used in mammalian cells, but whether it can be used during freezing boar semen is still unknown. The effects of RSV treatment during boar semen freezing on its anti-freezing ability, apoptosis, and possible apoptotic pathways were observed in this study. Sperm motility, mitochondrial membrane potential (ΔΨm), adenosine triphosphate (ATP) content, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic state, and messenger RNA (mRNA) expression levels of apoptotic genes involved in different apoptotic pathways after freezing with or without RSV treatment were tested. The results showed that: (1) Compared with fresh sperm, the motility, normal acrosome rate, and plasma membrane integrity rate of frozen boar sperm decreased significantly (P<0.05), and RSV did not significantly increase the sperm motility (0.44 vs. 0.40, P>0.05), but it did significantly improve the normal acrosome rate (57.65% vs. 47.00%, P<0.05) and plasma membrane integrity rate (46.67% vs. 38.85%, P<0.05). (2) After freezing, most boar sperm showed low mitochondrial ΔΨm. RSV treatment could increase the rate of high mitochondrial ΔΨm of boar sperm. (3) RSV treatment significantly decreased reactive oxygen species (ROS) levels (58.65% vs. 88.41%, P<0.05) and increased the ATP content (0.49 µmol/L vs. 0.25 µmol/L, P<0.05) of boar sperm during freezing. (4) The apoptotic rate of the freezing group (80.41%) with TUNEL detection increased significantly compared to the fresh group (9.70%, P<0.05), and RSV treatment greatly decreased the apoptotic rate (68.32%, P<0.05). (5) Real-time polymerase chain reaction (RT-PCR) showed that not only the genes from the death receptor-mediated apoptotic pathway (tumor necrosis factor-α (TNF-α), Fas ligand (FasL), and Caspase-8), but also the genes from the mitochondria-mediated apoptotic pathway (manganese superoxide dismutase (MnSOD), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-9) were both significantly changed after freezing. RSV treatment during freezing greatly changed their expression levels. Although RSV treatment during boar semen freezing did not significantly increase motility after thawing, it still played an efficient antioxidant role, which could enhance the mitochondrial function and decrease the apoptotic level induced by both the death receptor- and mitochondria-mediated apoptotic pathways.

The Signaling Mechanism of TGF-ß1 Induced Bovine Mammary Epithelial Cell Apoptosis.

The present study showed that Transforming growth factor beta 1 (TGF-ß1) can induce apoptosis of bovine mammary epithelial cells. This apoptosis was also observed with phosphorylation of Smad2/3 within 0.5-2 h. Afterwards the signal transferred into the nucleus. Moreover, intracellular free Ca(2+) concentration was significantly elevated as well as Caspase-3 activated and DNA lysised, thereby inducing the programmed cell death. This signaling pathway of TGF-ß1 was blocked by SB-431542 (10(-2) µM) via inhibiting ALK-5 kinase activity, which thus reversed the anti-proliferation and apoptosis effect of TGF-ß1 in mammary epithelial cells. These results indicated that TGF-ß1 induced apoptosis of bovine mammary epithelial cells through the ALK-5-Smad2/3 pathway, which plays an important role in inhibiting survival of mammary epithelial cells. Moreover, intracellular Ca(2+) also played a critical role in TGF-ß1-induced cell apoptosis.

[Establishment of a bovine epithelial mammary cell line and its ultrastructural changes when exposed to heat stress].

A simple method of trypsin/collagenase I alternative digestion and iterative culture flask adherence to discard fibroblasts for bovine mammary cell culture was established in this study. By immunohistochemistry, flow cytometry, western blot, Electron microscopy analysis, the characteristics of bovine mammary cells were investigated in vitro. Effect of hyperthermia on the cell ultrastructures was also observed. The results showed that the mammary cells were diploid epithelia with intact 30 pairs chromatins, which could secrete alpha-casein into the medium. After exposed to hyperthermia, the cell condensed chromatin like crescent on the nuclei verges, mitochondria occurred expansion and vacuolization, and apoptotic bodies appeared, which suggested that heat stress could induce apoptosis of the mammary epithelia.

[Comparative study on in vitro stationary culture system or superfusion culture system of cow mammary tissue].

Dairy cow mammary tissue was cultured in superfusion system or stationary system, and the influence of these two methods in the activity and ultrastructure of tissue was investigated according to LDH vigor, trypan blue dying, agrose gel electrophoresis, transmission microscope observation. The results showed that the mammary tissue cultured in superfusion system could keep normal tissue activity and ultrastructure within 12-60 h in DMEM plus 10% calf serum, while mammary tissue stationary culture could keep normal tissue activity and ultrastructure within 60-108 h. Both culture systems had some advantages and disadvantages.