Effects of Taurine on Broiler Aortic Endothelial Apoptosis Induced by Heat Stress

Heat stress is an environmental factor that causes severe economic loss to the current intensive breeding industry and induces huge impact on the long-term growth in livestock and poultry industry. Many animal experiments confirmed that heat stress is a major cause of heat stroke death, which is due to severe damage to endothelial cells. In order to provide a theoretical basis for the treatment or mitigation of heat stress related diseases in broilers, the effect of taurine on injury and apoptosis of aortic endothelial cells in broilers under heat stress was investigated in the present study. Ten days healthy broilers were sacrificed, then aortic tissue was used to isolate and cultivate primary broiler aortic endothelial cells. The third to the fifth generations of cells were used in the experiment. The cells were randomly divided into five groups, including control group (C), heat stress group (HS), low taurine (HS+LTau) group, mild taurine (HS+MTau) group and high taurine (HS+HTau) group. Cells in all groups were cultivated for 24 h in cell incubator (37 °C, 5% CO₂). Then the heat stress group cells were cultivated in a 43 °C thermostatic water bath for 6 h under heat stress, and then re-incubated under 37 °C for 1 h. The results showed that compared with the control group, expression levels of Bax, Caspase-9, Caspase-3, Cyt-c, P53 and other pro-apoptosis factors in HS groups were significantly increased (P < 0.05), while expression levels of anti-apoptosis factor Bcl-2 showed a significant decrease (P < 0.05). Compared with HS group, expression levels of Bcl-2 in endothelial cells were significantly increased by taurine administration (P < 0.05), while expression of Bax, Caspase-9, Caspase-3, Cyt-c and P53 were significantly increased by taurine (P < 0.05). In summary, the present data indicated that taurine could protect against injury and apoptosis of aortic endothelial cells under heat stress by inhibiting the activation of mitochondria-mediated apoptotic pathways.