| The relationship between the antioxidant index and lymphocyte apoptosis wasstudied by investigating physiological changes, peripheral-blood lymphocyte apoptosis, cellcycle and the antioxidant index of 40 Holstein cows, which had identical body weight,parities and milk yield under different temperature. The results showed that:1 The influence of temperature on the rectal temperature and respiratoryrate of the cowsThe influence of temperature on the rectal temperature and respiratory of dairy cowswas analyzed in this part. The values of temperature-humidity index (THI) of the dairyhouse, were all above 72 in summer, that is to say, the dairy cows were all under thecondition of heat stress. The rectal temperature and respiratory rate were significantlyhigher in summer when the cows were suffering from heat stress (P＜0.01). The rectaltemperature and respiratory rate of the cows reached the highest point when the temperatureof dairy house was 33.17℃.2 The influence of temperature on lymphocyte apoptosis in peripheralbloodThe influence of temperature on lymphocyte apoptosis in peripheral blood was testedby FCM. The results were as follows:(1) When temperature reached 33.17℃, peripheral-blood lymphocyte apoptosis ratereached 17.79％, indicating that heat stress significantly increased peripheral-bloodlymphocyte apoptosis.(2) At 28.53℃, the percent of ceils at G0/G1 phase reached the lowest, while thepercent of cells at the highest at S and G2/M phase reached the highest. Compared with the control group, all of the three phases were extremely different (P＜0.01). Lymphocyteapoptotic peak appeared in summer, and it reached the highest at 33.17℃. The lymphocyte proliferationindex was reached the highest at 28.53℃.3 The influence of different temperature on the Antioxidant Index inperipheral blood.The changes of antioxidant index in peripheral blood of different experimental groupswere analyzed, the results suggested that: the activities of superoxide dismutase-(SOD)and glutathione peroxidase (GSH-PX) in peripheral blood of the dairy cows reducedsignificantly in summer than those in winter, and reached the lowest at 33.17℃. The valuesof SOD and GSH-PX decreased by 52.30％and 37.10％comparing to the control groups.The activity of malondialdehyde (MDA) increased significantly in summer (P＜0.01), andit reached the highest at 33.17℃. The activity of anti-reactive oxygen species (anti-ROS)reached the lowest at 33.17℃.4 The relationship between the antioxidant index in peripheral blood andlymphocyte apoptosisThe relationship between the antioxidant index and lymphocyte apoptosis wasanalyzed, the results indicated that: the activities of GSH-PX,SOD and anti-ROS werenegatively correlated with the ratios of apoptosis of lymphocytes (r=-0.564, P＜0.01), (r=-0.675, P＜0.01) and (r=-0.789, P＜0.01); the content of MDAwas positively correlatedwith the ratios of apoptosis of lymphocytes (r=0.589, P＜0.01).The results showed that:(1) Heat stress had significant influence on the rectal temperature and respiratory rateof the cows.(2) High temperature had significant influenced on the cell cycle, the antioxidant indexand peripheral-blood lymphocyte apoptosis.(3) The change of cell cycle and the antioxidant index had certain correlation withperipheral-blood lymphocyte apoptosis. |
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