低剂量胰岛素对重度烧伤早期大鼠脏器氧化还原的影响

Effects of low-dose insulin on oxidation-reduction in rat organs after major burns

目的 探讨低剂量胰岛素对重度烧伤早期大鼠心脏、肾脏组织氧化还原的影响.方法 24只雄性SD大鼠按随机数字表法分为假伤组、烫伤组与治疗组各8只.假伤组浸入37 ℃温水中15 s模拟烫伤,伤后不进行液体复苏;烫伤组及治疗组（95.0±0.5） ℃热水中15 s制作烧伤总面积30%、Ⅲ度烫伤模型,伤后立即腹腔注射生理盐水（40 ml/kg）;治疗组复苏补液后皮下注射胰岛素（1.0 U·kg-1·d-1）,烫伤组同法注射等量生理盐水.伤后24 h采集腹主动脉血及心脏、肾脏组织标本.采用分光光度法测定血糖及心脏、肾脏组织中氧化及抗氧化指标,包括丙二醛（MDA）、黄嘌呤氧化酶（XO）、髓过氧化物酶（MPO）、总超氧化物歧化酶（T-SOD）、超氧化物歧化酶（SOD）1和2、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPx）.结果 烫伤组心脏、肾脏组织MDA含量、XO及MPO活力均显著高于假伤组（均P＜0.05）;与烫伤组比较,治疗组心脏组织MDA含量、XO活力均显著降低[（0.85±0.07）比（1.11±0.07） nmol/mg,（69.72±1.94）比（77.21±2.10） U/g],心脏、肾脏组织MPO活力也均显著降低（均P＜0.05）;与假伤组比较,烫伤组心脏、肾脏组织的T-SOD、CAT、GPx活力均显著降低,肾脏组织SOD1活力显著降低而SOD2活力显著升高,心脏组织SOD2活力显著降低（均P＜0.05）;与烫伤组比较,治疗组心脏组织T-SOD、SOD1活力均显著升高[（83.5±2.5）比（79.6±3.2）、（62.8±2.3）比（58.8±3.0） U/mg],心脏、肾脏组织CAT、GPx活力也均显著升高（均P＜0.05）;烫伤组、治疗组血糖水平均显著高于假伤组[（7.81±0.30）、（7.19±0.22）比（6.30±0.24） mmol/L],而治疗组显著低于烫伤组[（7.81±0.30） mmol/L]（均P＜0.05）.结论 低剂量胰岛素可干预重度烧伤早期大鼠心脏组织的脂质过氧化,对心脏、肾脏氧化还原的影响存在差异.

Objective To explore the effects of low-dose insulin on oxidation-reduction of heart and kidney in rats immediately after severe bums. Methods Twenty four male Sprague-Dawley （SD） rats were randomly divided into 3 groups of sham bum, burn and treatment （ n = 8 each）. The sham burn group was placed into 37 ℃ warm water for 15 seconds to simulate burn process and received no fluid replacement. The burn and treatment groups were immmersed into （95 ± 0. 5） ℃ hot water for 15 seconds to make a rat model of 30% total bum surface area, 111 degree burn injury and immediately received an intraperitoneal injection of physiological saline （40 ml/kg）. At the same time, a subcutaneous injection of insulin （1.0 U · kg-1 · d-1 ） was given in the treatment group and a subcutaneous injection of same-volume physiological saline in the burn group. The rats were sacrificed after 24 post-scald hours （ PSH ）. Abdominal aortic blood was collected for an analysis of blood glucose. The oxidation and antioxidation parameters of heart and kidney, such as malondialdehyde （ MDA）, xanthine oxidase （ XO）, myeloperoxidase （ MPO）, total superoxide dismutase （T-SOD）, superoxide dismutase 1, 2 （SOD1, 2）, catalase （CAT） and glutathion peroxidase （GPx）, were detected by spectrophotometry. Results Compared with the sham burn group, MDA content, XO and MPO activities of heart and kidney were significantly higher in the burn group （ all P 〈 0.05 ） ; in the treatment group, MDA content and XO activity of heart were significantly lower than the burn group （ （0. 85 ± 0. 07） vs （1.11 ±0. 07） nmol/mg, （69.72 ± 1.94） vs （77. 21 ±2. 10） U/g） while the MPO activities of heart and kidney were significantly lower （ all P 〈 0.05 ）. compared with the sham burn group, the activities of T-SOD, CAT, GPx of heart and kidney were significantly lower in the burn group, SOD1 activity of kidney was significantly lower, but SOD2 activity of kidney was significantly higher while SOD2 activity of heart was significantly lower （ all P 〈 0. 05 ） ; Compared with the burn group, the activities of T-SOD and SOD1 of heart in the treatment group were significantly higher （ （ 83.5 ± 2. 5 ） vs （79. 6 ± 3.2）, （ 62. 8 ± 2. 3 ） vs （ 58.8 ± 3.0） U/mg）, CAT and GPx activity of heart and kidney were significantly higher （ all P 〈 0. 05 ）. Compared with the sham bum group, blood glucose in the burn and treatment group were significantly higher （（7.81 ± 0.30）, （7.19 ± 0.22） vs （6.30 ± 0.24） mmol/L） and blood glucose in the treatment group was significantly lower than the burn group（ （7.81 ±0. 30） mmol/L） （all P 〈0. 05）. Conclusions During an early stage, a low-dose insulin may intervene in heart tissue lipid peroxidation of severely burned rats. And differences exist in the effects of oxidation-reduction between heart and kidney.