芹菜素对深Ⅱ度烧伤模型大鼠急性肺损伤保护作用及机制研究

Protective effect of Apigenin on acute lung injury in a rat model of severe second-degree burn

目的探讨芹菜素对深Ⅱ度烧伤模型大鼠急性肺损伤的保护作用及其机制。方法Wistar大鼠180只,按随机数字表法分为假烧伤组(0.9%氯化钠溶液)、模型组(0.9%氯化钠溶液)、地塞米松5mg/kg组和芹菜素12.5、25、50mg/kg组,除假烧伤组外,均通过烫伤仪(温度106℃、压力0.03MPa、持续时间5s)制备深Ⅱ度烧伤模型大鼠,相应药物治疗14天。检测各组大鼠肺功能指标,计算肺指数,苏木精-伊红(HE)染色法行肺组织病理学检查并行损伤评分,原位末端转移酶标记(TUNEL)法观察肺细胞凋亡,透射电子显微镜观察肺细胞超微结构改变;生化分析法检测肺组织髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量,酶联免疫吸附试验(ELISA)检测炎症细胞因子[肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)]含量。结果与模型组比较,地塞米松5mg/kg组和芹菜素25、50mg/kg组大鼠呼吸频率降低[(100.13±5.69)次/min、(108.72±6.81)次/min、(98.27±5.58)次/min比(116.04±7.25)次/min,P<0.05或P<0.01]、肺泡通透指数降低[(2.74±0.42)、(2.88±0.46)、(2.19±0.37)比(3.92±0.57),P<0.01]、氧分压(PaO2)升高[(6.71±1.30)kPa、(6.59±1.34)kPa、(8.24±1.76)kPa比(4.05±0.86)kPa,P<0.01]、肺指数降低[(5.16±0.65)、(5.18±0.71)、(4.53±0.68)比(5.93±0.85),P<0.05或P<0.01];肺组织形态结构病变、细胞凋亡状况和肺细胞超微结构病变均明显改善,损伤评分降低[(7.76±0.91)分、(7.15±1.12)分、(4.89±0.75)分比(10.73±1.74)分,P<0.01],凋亡指数(AI)降低[(36.90±6.45)%、(34.19±6.28)%、(22.14±4.67)%比(51.27±8.03)%,P<0.01];SOD活性升高[(58.47±8.70)U/mg、(62.98±9.04)U/mg、(69.13±9.37)U/mg比(48.19±8.24)U/mg,P<0.05或P<0.01]且MDA含量降低[(4.56±0.92)nmol/mg、(4.29±0.82)nmol/mg、(3.02±0.71)nmol/mg比(5.64±1.10)nmol/mg,P<0.05或P<0.01]、TNF-α含量降低[(84.82±11.03)pg/mL、(94.17±12.68)pg/mL、(63.84±9.01)pg/mL比(126.75±15.41)pg/mL,P<0.01]、IL-1β含量降低[(0.69±0.16)pg/mL、(0.98±0.17)pg/mL、(0.57±0.13)pg/mL比(1.40±0.29)pg/mL,P<0.01]、IL-6含量降低[(104.17±13.99)pg/mL、(135.93±15.02)pg/mL、(97.85±12.16)pg/mL比(183.82±18.15)pg/mL,P<0.01];芹菜素25、50mg/kg组大鼠MPO活性升高[(1.29±0.37)U/g、(1.40±0.39)U/g比(0.99±0.24)U/g,P<0.05或P<0.01]、CAT活性升高[(24.05±5.36)U/mg、(26.24±5.48)U/mg比(17.92±4.33)U/mg,P<0.05或P<0.01]。与地塞米松5mg/kg组比较,芹菜素50mg/kg组大鼠呼吸频率、肺组织CAT、IL-1β及IL-6含量无明显差异(P>0.05),余指标芹菜素50mg/kg组改善更显著(P<0.05或P<0.01)。结论芹菜素对深Ⅱ度烧伤大鼠急性肺损伤具有保护作用,可能与抑制氧化应激和炎症反应有关。

Objective To investigate the protective effect of Apigenin on acute lung injury in a rat model of severe second-degree burn and the underlying mechanisms.Methods A total of 180 Wistar rats were randomly divided into six groups,i.e.,sham plus normal saline,model plus normal saline,model plus dexamethasone(5mg/kg),and model plus Apigenin(12.5,25,and 50mg/kg)groups.The model groups of rats underwent severe second-degree burn using an apparatus with 106℃and 0.03MPa pressure for five seconds.The drugs were then administrated i.p.for 14 days.The lung functions of mice were assessed and the lung function index was calculated,lung tissues were subjected to H&E staining and lung injury was evaluated using the injury score,and lung cell apoptosis was assayed using the TUNEL method.The lung ultra-structures were examined using the transmission electron microscope.The myeloperoxidase(MPO),superoxide dismutase(SOD),catalase(CAT),and MDA levels in lung tissues were analyzed by a biochemical analyzer,while levels of inflammatory cytokines,including tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6),were detected using the ELISA.Results Compared with the model group,the dexamethasone(5mg/kg)and Apigenin(25 or 50mg/kg)groups showed decreased respiratory rate(100.13±5.69,108.72±6.81,and 98.27±5.58time/min vs.116.04±7.25time/min;P<0.05 or P<0.01),decreased alveolar permeability index(2.74±0.42,2.88±0.46,and 2.19±0.37 vs.3.92±0.57;P<0.01),decreased lung function index(5.16±0.65,5.18±0.71,and 4.53±0.68 vs.5.93±0.85;P<0.05 or P<0.01),but increased PaO2(6.71±1.30,6.59±1.34,and 8.24±1.76KPa vs.4.05±0.86KPa;P<0.01).Moreover,these treatments significantly improved the lung tissue morphology and reduced lung cell apoptosis and lung cell ultrastructural lesions,i.e.,the injury score was decreased(7.76±0.91,7.15±1.12,and 4.89±0.75 vs.10.73±1.74;P<0.01)and lung cell apoptosis index(AI)was reduced(36.90±6.45,34.19±6.28 and 22.14±4.67 vs.51.27±8.03;P<0.01).In addition,activity of SOD was increased(58.47±8.70,62.98±9.04,69.13±9.37 vs.48.19±8.24U/mg;P<0.05 or P<0.01)and there was a decreased level of MDA(4.56±0.92,4.29±0.82,and 3.02±0.71 vs.5.64±1.10nmol/mg;P<0.05 or P<0.01),TNF-α(84.82±11.03,94.17±12.68,and 63.84±9.01 vs.126.75±15.41pg/mL;P<0.01),IL-1β(0.69±0.16,0.98±0.17,and 0.57±0.13 vs.1.40±0.29pg/mL;P<0.01),and IL-6(104.17±13.99,135.93±15.02,and 97.85±12.16 vs.183.82±18.15pg/mL;P<0.01).Compared with the model group,rats in the Apigenin 25 and 50mg/kg groups had an increased level of MPO(1.29±0.37 and 1.40±0.39 vs.0.99±0.24U/g;P<0.05)and CAT(24.05±5.36 and 26.24±5.48 vs.17.92±4.33U/mg;P<0.05 or P<0.01).Compared with dexamethasone(5mg/kg)group,rats in Apigenin(50mg/kg)group showed no significant changes in respiratory rate,CAT,IL-1βand IL-6(P>0.05), while improved significant,ly in other indicators(P<0.05 or P<0.01). Conclusion Apigenin possesses a protective effect against acute lung in,jury in a rat model of severe second-degree burns through inhibition of the oxidative stress and inflammation.