Zinc alleviates the heat stress of primary cultured hepatocytes of broiler embryos via enhancing the antioxidant ability and attenuating the heat shock responses

Abstract

Zinc (Zn) has been shown to attenuate the adverse effects of heat stress on broilers, but the mechanisms involving this process remain unclear. We aimed to investigate possible protective mechanisms of Zn on primary cultured hepatocytes of broiler embryos subjected to heat stress. Three experiments were conducted. In Exp. 1, hepatocytes were treated with 0, 50, 100, 200, or 400 μmol/L added Zn as inorganic Zn sulfate (iZn) for 12, 24 or 48 h. In Exp. 2, cells were exposed to 40 °C (a normal temperature [NT]) and 44 °C (a high temperature [HT]) for 1, 2, 4, 6, or 8 h. In Exp. 3, cells were preincubated with 0 or 50 μmol/L Zn as iZn or organic Zn lysine chelate (oZn) for 8 h under NT, and then incubated with the same Zn treatments under NT or HT for 4 or 6 h. The biomarkers of antioxidative status and heat stress in cells were measured. The results in Exp. 1 indicated that 50 μmol/L Zn and 12 h incubation were the optimal conditions for increasing antioxidant ability of hepatocytes. In Exp. 2, the 4 or 6 h incubation under HT was effective in inducing heat shock responses of hepatocytes. In Exp. 3, HT elevated ( P < 0.01) malondialdehyde content and expressions of heat shock protein 70 ( HSP70 ) mRNA and protein, as well as HSP9 0 mRNA. However, Zn supplementation increased ( P < 0.05) copper zinc superoxide dismutase (CuZnSOD) activity and metallothionein mRNA expression, and effectively decreased ( P < 0.05) the expressions of HSP7 0 mRNA and protein, as well as HSP9 0 mRNA. Furthermore, oZn was more effective ( P < 0.05) than iZn in enhancing CuZnSOD activity of hepatocytes under HT. It was concluded that Zn (especially oZn) could alleviate heat stress of broiler hepatocytes via enhancing their antioxidant ability and attenuating heat shock responses.

Mechanisms Underlying the Protective Effect of Maternal Zinc (ZnSO4 or Zn-Gly) against Heat Stress-Induced Oxidative Stress in Chicken Embryo

“…CuZn-SOD and MT are considered as endogenous ROS scavengers that confer protection against oxidative stress in vivo [ 38 , 39 ]. Related studies have shown that heat stress can lead to increased CuZn-SOD and MT mRNA abundance expression in hepatocytes [ 40 ]. Against our experimental results, this may be due to the destructive effect of excessive ROS on post-transcriptional Nrf2.…”

“…Therefore, zinc plays an important role under heat stress conditions. Zinc can effectively attenuate the heat-shock responses with down-regulated expressions of HSP70 mRNA in broilers [ 40 ]. Meanwhile, zinc can also adjust abnormal levels of the MDA and 8-OHdG in tissue and serum to decrease the oxidative damage caused by heat stress in broilers [ 49 ].…”

The Effects of Inorganic Phosphorus Levels on Phosphorus Utilization, Local Bone-Derived Regulators, and BMP/MAPK Pathway in Primary Cultured Osteoblasts of Broiler Chicks

“…After 24 d treatments with various P concentrations, the mRNA expression levels of local bone-derived regulator genes ( FGF23, MEPE, DMP1 and PHEX ) and BMP/MAPK pathway-related genes [BMP2, extracellular signal-regulated kinase 1 (ERK1), c-Jun N-terminal kinase 1 (JNK1) and p38 mitogen-activated protein kinase alpha (p38α)] were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR) as described by Li et al ( 31 ). Briefly, according to the manufacturer's instruction, PrimeScriptTM RT Master Mix kit (TaKaRa, Dalian, China) was used to reverse RNA into cDNA.…”

Effect of in ovo manganese injection on the embryonic development, antioxidation, hatchability, and performances of offspring broilers under normal and high temperatures

“…The protocol for PCR was as follows: denaturation at 95°C for 2 min followed by 40 cycles of 95°C for 60 s, 60°C for 30 s, and 72°C for 30 s. The geometric means of β -actin and glyceraldehyde 3-phosphate dehydrogenase ( GAPDH ) were used as references to normalize the expression of the target gene. The internal references and calculation of the relative mRNA expression for MnSOD target gene were used as described previously ( Li et al., 2021 ). The primer sequences are listed in Table 3 .…”