叔丁基对苯二酚对热应激小鼠肝脏氧化损伤的缓解作用

Tert-Butylhydroquinone: Preventive Effects on Heat Stress-Induced Oxidative Damage in Liver of Mice

本试验旨在研究叔丁基对苯二酚(tBHQ)对热应激小鼠肝脏氧化损伤的影响。试验选用50只6周龄ICR雄性小鼠随机分为2组,每组25只,tBHQ(-)组饲喂基础饲粮,tBHQ(+)组饲喂基础饲粮中添加1%tBHQ的试验饲粮。饲喂14 d后,小鼠每天进行42℃2 h热应激处理,连续8 d。在热应激之前(热应激0 d)和热应激1、2、4、8 d,每组各取5只小鼠处死,采集肝脏,测定肝脏重量和抗氧化指标,免疫组织化学方法检测转录因子E2相关因子2(Nrf2)和血红素加氧酶1(HO-1)蛋白表达,实时定量PCR法测定Nrf2及其调控表达基因的表达量。结果表明:1)tBHQ(-)组肝脏指数在热应激4 d恢复正常水平,而tBHQ(+)组在热应激2 d即恢复正常水平。2)与tBHQ(-)组相比,热应激0 d,tBHQ(+)组肝脏总超氧化物歧化酶(T-SOD)活力显著升高(P<0.05),在热应激4 d时,还原型谷胱甘肽含量以及T-SOD、铜,锌超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶活力显著降低(P<0.05)。3)热应激2 d,tBHQ(-)组比tBHQ(+)组肝脏损伤情况更为严重。4)热应激0 d,tBHQ(-)组未检测到Nrf2蛋白在肝脏组织表达,热应激后各时间点都检测到Nrf2蛋白的表达,而tBHQ(+)组在各阶段均有表达;tBHQ(-)组在热应激0、1、4和8 d都检测到HO-1蛋白的表达,而tBHQ(+)组在热应激0、1和2 d时检测到了HO-1蛋白的表达。5)与tBHQ(-)组相比,tBHQ(+)组多个Kelch样ECH相关蛋白(Keap1)-Nrf2/ARE信号通路相关基因表达量均显著升高(P<0.05)。综上所述,饲粮添加1%tBHQ对热应激造成的小鼠肝脏氧化损伤能够起到一定的缓解作用。

To investigate the effects of tert-butylhydroquinone （tBHQ） on heat stress-induced oxidative dam- age in liver of mice, fifty six-week-old ICR male mice were divided into 2 groups with 25 mice in each group. tBHQ （-） group received a basal diet, and tBHQ （＋） group received the basal diet supplemented with 1% tBHQ. After 14 days of feeding, mice were exposed to the elevated ambient temperature （ 42 ℃ ） daily for 2 h. During the period of 8 consecutive days, five mice in each group were sacrificed to collect liver before heat stress （0 day after heat stress） and at 1, 2, 4 and 8 days after heat stress, respectively. Liver weight and an- tioxidative indices were determined, transcription factor E2 related factor 2 （Nrf2） and heine oxygenase-1 （HO-1） protein expressions in liver were determined by immunohistochemical detection, and the expressions of Nrf2 gene and Nrf2-regulated genes were analyzed by real time-PCR detection. The results showed as fol- lows ： 1 ） liver index of tBHQ （-） group recovered to normal level at 4 days after heat stress, while that of tB- HQ （＋） group recovered to normal level at 2 days after heat stress. 2） Compared with tBHQ （-） group, total superoxide dismutase （ T-SOD ） activity of tBHQ （＋） group was significantly increased at 0 day after heat stress （P〈0.05）, and reduced glutathione hormone （GSH） content and the activities of T-SOD, copper, zinc-superoxide dismutase （ Cu, Zn-SOD） , glutathione peroxidase （GSH-Px） and catalase （CAT） of tBHQ （＋） group were significantly reduced at 4 days after heat stress （P〈0.05）. 3） At 2 days after heat stress, liver injury of tBHQ （-） group was more serious than that of tBHQ （＋） group. 4） Nrf2 protein expression was not detected in liver at 0 day after heat stress, but it was detected at all the time points after heat stress of tBHQ （-） group and was detected at all the time points of tBHQ （＋） group; HO-1 protein expression was detected in liver at 0, 1, 4 and 8 days after heat stress of tBHQ （-） group, and at 0, 1 and 2 days after heat stress of tBHQ （＋） group. 5） Compared with tBHQ （-） group, multiple genes of kelch-like ECH-associated protein 1 （Keapl）-Nrf2/ARE signing pathway of tBHQ （＋） group were significantly increased （P〈0.05）. In conclusion, dietary supplementation of 1% tBHQ can alleviate heat stress-induced oxidative damage in liver of mice.