A high concentrate diet inhibits forkhead box protein A2 expression, and induces oxidative stress, mitochondrial dysfunction and mitochondrial unfolded protein response in the liver of dairy cows.

High-concentrate diet induce subacute ruminal acidosis (SARA) and cause liver damage in ruminants. It has been reported that forkhead box protein A2 (FOXA2) can enhance mitochondrial membrane potential but its function in mitochondrial dysfunction induced by high concentrate diets is still unknown. Therefore, the aim of this study was to elucidate the effect of high-concentrate (HC) diet on hepatic FOXA2 expression, mitochondrial unfolded protein response (UPRmt), mitochondrial dysfunction and oxidative stress. A total of 12 healthy mid-lactation Holstein cows were selected and randomized into 2 groups: the low concentrate (LC) diet group (concentrate:forage = 4:6) and HC diet group (concentrate:forage = 6:4). The trial lasted 21 d. The rumen fluid, blood and liver tissue were collected at the end of the experiment. The results showed that the rumen fluid pH level was reduced in the HC group and the pH was lower than 5.6 for more than 4 h/d, indicating that feeding HC diets successfully induced SARA in dairy cows. Both FOXA2 mRNA and protein abundance were significantly reduced in the liver of the HC group compared with the LC group. The activity of antioxidant enzymes (CAT, G6PDH, T-SOD, Cu/Zn SOD, Mn SOD) and mtDNA copy number in the liver tissue of the HC group decreased, while the level of H2O2 significantly increased, this increase was accompanied by a decrease in oxidative phosphorylation (OXPHOS). The balance of mitochondrial division and fusion was disrupted in the HC group, as evidenced by the decreased mRNA level of OPA1, MFN1, and MFN2 and increased mRNA level of Drp1, Fis1, and MFF. At the same time, HC diet downregulated the expression level of SIRT1, SIRT3, PGC-1α, TFAM, and Nrf 1 to inhibit mitochondrial biogenesis. The HC group induced UPRmt in liver tissue by upregulating the mRNA and protein levels of CLPP, LONP1, CHOP, Hsp10, and Hsp60. In addition, HC diet could increase the protein abundance of Bax, CytoC, Caspase 3 and Cleaved-Caspase 3, while decrease the protein abundance of Bcl-2 and the Bcl-2/Bax ratio. Overall, our study suggests that the decreased expression of FOXA2 may be related to UPRmt, mitochondrial dysfunction, oxidative stress, and apoptosis in the liver of dairy cows fed a high concentrate diet.

Aqua-bis-(3,5-dimethyl-1H-pyrazole-κN)(oxydiacetato-κO,O',O'')copper(II) dihydrate.

In the title compound, [Cu(C(4)H(4)O(5))(C(5)H(8)N(2))(2)(H(2)O)]·2H(2)O, the Cu(II) cation assumes a distorted octa-hedral coordination geometry formed by two 3,5-dimethyl-1H-pyrazole ligands, one oxydiacetate (ODA) dianion and one coordinated water mol-ecule. The tridentate ODA ligand chelates to the Cu cation in a facial configuration with a longer Cu-O bond [2.597 (3) Å], and both chelating rings display envelope conformations. In the mol-ecule, the two pyrazole rings are twisted with respect to each other at a dihedral angle of 57.5 (3)°. Extensive inter-molecular O-H⋯O and N-H⋯O hydrogen bonding is present in the crystal structure.

Aqua-(2,2'-diamino-4,4'-bi-1,3-thia-zole-κN,N)(thio-diacetato-κO,S,O')nickel(II) monohydrate.

In the title compound, [Ni(C(4)H(4)O(4)S)(C(6)H(6)N(4)S(2))(H(2)O)]·H(2)O, the Ni(II) cation assumes a distorted octa-hedral coordination geometry formed by a diamino-bithia-zole (DABT) ligand, a thio-diacetate (TDA) dianion and a coordinated water mol-ecule. The tridentate TDA chelates to the Ni cation in a facial configuration, and both chelating rings display the envelope conformations. The two thia-zole rings of the DABT ligand are twisted with respect to each other, making a dihedral angle of 9.96 (9)°. Extensive O-H⋯O, N-H⋯O and weak C-H⋯O hydrogen bonding is present in the crystal structure.

Aqua-(2,2'-diamino-4,4'-bi-1,3-thia-zole-κN,N)(pyridine-2,6-dicarboxyl-ato-κO,N,O)zinc tetra-hydrate.

The title compound, [Zn(C(7)H(3)NO(4))(C(6)H(6)N(4)S(2))(H(2)O)]·4H(2)O, assumes a distorted octa-hedral coordination geometry around the Zn(2+) cation, formed by a diamino-bithia-zole (DABT) mol-ecule, a pyridine-2,6-dicarboxyl-ate anion and a water mol-ecule. The pyridine-2,6-dicarboxyl-ate anion chelates to the Zn(II) atom with a facial configuration. Within the chelating DABT ligand, the two thia-zole rings are twisted by a dihedral angle of 14.52 (8)° with respect to each other. O-H⋯O and N-H⋯O hydrogen bonds occur in the crystal structure.