Effects of L-Arginine on neutrophil apoptosis induced by heat stress in dairy cows
This study aims to investigate the effect of heat stress on the apoptosis of polymorphonu-clear granulocyte(PMN)in dairy cows,and to investigate whether L-arginine(L-Arg)has a pro-tective effect on PMN induced by heat stress.In vitro test models were constructed using isolated and cultured PMN from healthy dairy cows,which were divided into the control group(Con group,37 ℃)and the experimental group(HS group,cultured at 42 ℃ for 0.0,0.5,1.0,1.5,2.0,2.5,3.0 h).Cell activity was detected by CCK-8 method,the optimal heat treatment time was de-termined to be 2.5 h.Then,the PMN isolated from healthy cows was pre-incubated with L-Arg at different concentrations(2,4,6,8,10 mmol/L)for 30 min,and then cultured at 42 ℃ for 2.5 h.CCK-8 method was used to detect the cell activity,and the optimal concentration of L-Arg was found to be 4 mmol/L.Western blot was used to detect the activation of heat shock protein 70(HSP70)and c-CASP 3,a key protein of apoptosis,and flow cytometry was used to measure the apoptosis rate of PMN.The results showed that compared with the Con group,after PMN culture at 42 ℃ for 2.5 h,in the HS group,the expression of HSP70 protein was significantly increased(P＜0.01),and the protein abundance ratio of c-CASP 3 to CASP 3 was significantly increased(P＜0.01).The apoptosis rate of PMN was significantly increased(P＜0.01).After incubating PMN with 4 mmol/L L-Arg and then cultured at 42 ℃ for 2.5 h,it was found that compared with the HS group,L-Arg could significantly reduce the protein abundance ratio of c-CASP 3 to CASP 3(P＜0.01),and significantly reduce the apoptosis rate of PMN(P＜0.05).These results suggest that heat stress can induce the apoptosis of PMN in dairy cows,and L-Arg can alleviate the proapoptotic effect of heat stress on PMN in dairy cows.
NETL
NSTL
万方数据
