Objective: To investigate the effects of hydrogen on the lung damage of mice at early stage of severe burn. Methods: One hundred and sixty ICR mice were divided into sham injury, hydrogen, pure burn, and burn+ hydrogen groups according to the random number table, with 40 mice in each group. Mice in pure burn group and burn+ hydrogen group were inflicted with 40% total body surface area full-thickness scald (hereafter referred to as burn) on the back, while mice in sham injury group and hydrogen group were sham injured. Mice in hydrogen group and burn+ hydrogen group inhaled 2% hydrogen for 1 h at post injury hour (PIH) 1 and 6, respectively, while mice in sham injury group and pure burn group inhaled air for 1 h. At PIH 24, lung tissue of six mice in each group was harvested, and then pathological changes of lung tissue were observed by HE staining and the lung tissue injury pathological score was calculated. Inferior vena cava blood and lung tissue of other eight mice in each group were obtained, and then content of high mobility group box 1 (HMGB1) and interleukin-6 (IL-6) in serum and lung tissue was determined by enzyme-linked immunosorbent assay. Activity of superoxide dismutase (SOD) in serum and lung tissue was detected by spectrophotometry. After arterial blood of other six mice in each group was collected for detection of arterial partial pressure of oxygen (PaO(2)), the wet and dry weight of lung tissue were weighted to calculate lung wet to dry weight ratio. The survival rates of the other twenty mice in each group during post injury days 7 were calculated. Data were processed with one-way analysis of variance, LSD test and log-rank test. Results: (1) At PIH 24, lung tissue of mice in sham injury group and hydrogen group showed no abnormality. Mice in pure burn group were with pulmonary interstitial edema, serious rupture of alveolar capillary wall, and infiltration of a large number of inflammatory cells. Mice in burn+ hydrogen group were with mild pulmonary interstitial edema, alveolar capillary congestion accompanied by slight rupture and bleeding, and the number of infiltration of inflammatory cells was smaller than that in pure burn group. The lung tissue injury pathological scores of mice in sham injury group, hydrogen group, pure burn group, and burn+ hydrogen group were (0.7±0.5), (0.8±0.5), (6.1±1.0), and (2.8±0.8) points, respectively. The lung tissue injury pathological score of mice in pure burn group was significantly higher than that in sham injury group (P<0.001). The lung tissue injury pathological score of mice in burn+ hydrogen group was significantly lower than that in pure burn group (P<0.001). (2) At PIH 24, the content of HMGB1 and IL-6 in serum and lung tissue of mice in hydrogen group was close to that in sham injury group (with P values above 0.05). The content of HMGB1 and IL-6 in serum and lung tissue of mice in pure burn group was significantly higher than that in sham injury group (with P values below 0.001). The content of HMGB1 and IL-6 in serum and lung tissue of mice in burn+ hydrogen group was significantly lower than that in pure burn group (with P values below 0.001). (3) At PIH 24, the activity of SOD in serum and lung tissue of mice in hydrogen group was close to that in sham injury group (with P values above 0.05). The activity of SOD in serum and lung tissue of mice in pure burn group was significantly lower than that in sham injury group (with P values below 0.001). The activity of SOD in serum and lung tissue of mice in burn+ hydrogen group was significantly higher than that in pure burn group (with P values below 0.001). (4) At PIH 24, there was no statistically significant difference in PaO(2) among the mice in four groups (F=0.04, P>0.05). (5) At PIH 24, the ratios of lung wet to dry weight of mice in sham injury, hydrogen, pure burn, and burn+ hydrogen groups were 3.52±0.22, 3.61±0.24, 7.24±0.32, and 5.21±0.41, respectively. The ratio of lung wet to dry weight of mice in pure burn group was significantly higher than that in sham injury group (P<0.001). The ratio of lung wet to dry weight of mice in burn+ hydrogen group was significantly lower than that in pure burn group (P<0.001). (6) The survival rates of mice in sham injury group and hydrogen group during post injury days 7 were 100%. Compared with those in sham injury group, survival rates of mice in pure burn group from post injury days 3 to 7 were significantly decreased (with P values below 0.05). Compared with those in pure burn group, survival rates of mice in burn+ hydrogen group from post injury days 5 to 7 were significantly increased (with P values below 0.05). Conclusions: Hydrogen can significantly alleviate the infiltration of inflammatory cells and improve the pathological lesions of lung tissue of mice with severe burn. It has the effects of reducing inflammatory reaction and inhibiting oxidative stress, further showing the protective effect on the lung of burn mice.
目的： 探讨氢气对重度烧伤小鼠早期肺损伤的影响。 方法： 取160只ICR小鼠，按随机数字表法分为假伤组、氢气组、单纯烧伤组、烧伤＋氢气组，每组40只。单纯烧伤组和烧伤＋氢气组小鼠背部制作40%TBSA Ⅲ度烫伤(以下称烧伤)模型，假伤组和氢气组小鼠模拟致假伤。分别于伤后1、6 h，氢气组和烧伤＋氢气组小鼠吸入体积分数2%氢气1 h，假伤组和单纯烧伤组小鼠吸入空气1 h。伤后24 h，各组取6只小鼠肺组织，行HE染色，观察肺组织病理变化，并计算肺组织损伤病理学评分。各组另取8只小鼠，取下腔静脉血和肺组织，采用ELISA法检测血清和肺组织中高迁移率族蛋白B1(HMGB1)、IL－6的含量，分光光度法检测血清和肺组织中SOD活性。各组另取6只小鼠，取动脉血测定PaO(2)，取肺组织，称量肺湿干质量，计算肺湿干质量比。计算各组剩余20只小鼠伤后7 d内的存活率。对数据行单因素方差分析、LSD检验和log－rank检验。 结果： (1)伤后24 h，假伤组和氢气组小鼠肺组织未见异常；单纯烧伤组小鼠肺间质水肿，肺泡毛细血管壁严重破裂，出现大量炎性细胞浸润；烧伤＋氢气组小鼠肺间质轻度水肿，肺泡毛细血管充血伴少量破裂出血，炎性细胞浸润较单纯烧伤组少。假伤组、氢气组、单纯烧伤组和烧伤＋氢气组小鼠肺组织损伤病理学评分分别为(0.7±0.5)、(0.8±0.5)、(6.1±1.0)、(2.8±0.8)分，单纯烧伤组小鼠肺组织损伤病理学评分较假伤组显著升高(P<0.001)，烧伤＋氢气组小鼠肺组织损伤病理学评分较单纯烧伤组显著降低(P<0.001)。(2)伤后24 h，氢气组小鼠血清和肺组织中HMGB1、IL－6含量与假伤组相近(P值均大于0.05)，单纯烧伤组小鼠血清和肺组织中HMGB1、IL－6含量较假伤组显著升高(P值均小于0.001)，烧伤＋氢气组小鼠血清和肺组织中HMGB1、IL－6含量较单纯烧伤组显著降低(P值均小于0.001)。(3)伤后24 h，氢气组小鼠血清和肺组织中SOD活性与假伤组相近(P值均大于0.05)，单纯烧伤组小鼠血清和肺组织中SOD活性较假伤组显著降低(P值均小于0.001)，烧伤＋氢气组小鼠血清和肺组织中SOD活性较单纯烧伤组显著升高(P值均小于0.001)。(4)伤后24 h，4组小鼠PaO(2)总体比较，差异无统计学意义(F＝0.04，P>0.05)。(5)伤后24 h，假伤组、氢气组、单纯烧伤组和烧伤＋氢气组小鼠肺湿干质量比分别为3.52±0.22、3.61±0.24、7.24±0.32、5.21±0.41，单纯烧伤组小鼠肺湿干质量比明显高于假伤组(P<0.001)，烧伤＋氢气组小鼠肺湿干质量比明显低于单纯烧伤组(P<0.001)。(6)假伤组和氢气组小鼠伤后7 d内存活率为100%。与假伤组比较，单纯烧伤组小鼠伤后3～7 d存活率均明显降低(P值均小于0.05)。与单纯烧伤组比较，烧伤＋氢气组小鼠伤后5～7 d存活率明显升高(P值均小于0.05)。 结论： 氢气能够显著减轻重度烧伤小鼠肺组织炎性细胞浸润和改善肺组织病理损伤，具有减轻炎症反应、抑制氧化应激的作用，进而对烧伤小鼠肺起到了保护作用。.
Keywords: Burns; HMGB1 protein; Hydrogen; Interleukin-6; Lung; Superoxide dismutase.