山羊烧伤和脓毒症中能量代谢动态变化的实验研究

Dynamic changes in metabolism in sheep after thermal injury and in sepsis

目的 观察和分析烧伤早期和脓毒症状态下的能量代谢动态变化及其影响因素。方法以山羊烧伤和脓毒症为模型检测血流动力学、静息能量消耗 (REE)、血内毒素、肿瘤坏死因子 α(TNF α)、白介素 6 (IL 6 )、白介素 8(IL 8)水平及有关代谢激素的水平 ,监测血糖、血乳酸及氨基酸谱的动态变化。 结果 (1)烧伤早期充分复苏的情况下REE即显著升高 ,随着合并内毒素血症的确立 ,REE升高更为显著 (35 2 5± 17 6 )J·h-1·m-2 ;(2 )烧伤及烧伤合并内毒素血症的情况下 ,血中内毒素、TNF α、IL 6、IL 8水平显著增高 ,在时相上与REE的升高相平行 ;(3)在烧伤后氧输送和氧耗量短暂下降 ,随休克复苏及脓毒症的确立逐渐升高 ,组织氧摄取率在烧伤早期短暂增高 ,之后则基本恢复正常水平 ;(4 )血清胰岛素、胰高血糖素、皮质醇等代谢相关激素水平在伤后均高于伤前 ;(5 )血乳酸、血糖、尿3 甲基组氨酸在烧伤后和脓毒症中均显著高于伤前水平。 结论 在烧伤尤其是合并脓毒症的情况下 ,机体存在显著的代谢增强过程。其与炎症介质 (TNF α、IL 6、IL 8的过度释放 )有关 ,并受相关代谢激素的调控。该模型较好地反映烧伤和脓毒症中以高代谢为特征的机体代谢紊乱过程。

Objective[WT5”BZ] To investigate the dynamic changes in contributory factors of energy expenditure and metabolism of glucose, proteins and fatty acid in early postburn phase and in sepsis. [WT5”HZ]Methods[WT5”BZ] Using flame burn and intravenous injection of endotoxin in sheep, we established an animal model of burn and sepsis. Changes in hemodyamics and REE were monitored continuously and circulating levels of endotoxin, TNF-α, IL-6, IL-8, and certain metabolic hormones were assayed accordingly. Dynamic changes in serum contents of glucose and lactate as well as the plasma amino acid spectrum were analyzed. [WT5”HZ]Results[WT5”BZ] The level of REE elevated significantly despite sufficient resuscitation in early postburn periods[(201 4±6 3) J·h -1 ·m -2 vs (165 2±14 3) J·h -1 ·m -2 ] and further elevated (352 5±17 6)J·h -1 ·m -2 with the establishment of endotoxemia after thermal injury. Systemic LPS[(0 19±0 02)-(0 33±0 04)EU·ml -1 vs (0 14±0 02)EU·ml -1 ], TNF-α[(156±31)-(330±45)pg·ml -1 vs (66±15)pg·ml -1 ], IL-6[(298±106)-(448±91)pg·ml -1 vs (213±65)pg·ml -1 ] and IL-8[(247±53)-(389±121)pg·ml -1 vs (180±98)pg·ml -1 ] increased significantly and were chronologically proportional to the elevation of REE. Oxygen delivery[(176±28)ml·min -1 ·m -2 vs (375±45)ml·min -1 ·m -2 ] and tissue oxygen consumption [(97±12)ml·min -1 ·m -2 vs (120±20)min -1 ·m -2 )]decreased temporarily in early postburn period and gradually elevated with resuscitation and the onset of sepsis. Plasma contents of insulin[(16 4±6 2)-(26 2±5 3)MU·ml -1 vs 15 3±4 8MU·ml -1 ), glucagon(219 6±77 0-330 4±96 1 ng·L -1 vs (200 3±166 8)ng·L -1 and cortisol[(25 2±6 7)ng·ml -1 vs (17 8± 3 5) ng·ml -1 ] increased in postburn period as compared with those of normal controls. Plasma contents of lactate[(9 8±1 7)-(15 0±5 0) mmol·ml -1 vs. (8 8±3 3) mmol·ml -1 , glucose[(5 8±0 8)-(10 8±2 1) mmol·ml -1 vs (4 7±0 7) mmol·ml -1 )]and urinary output of 3-MT[(275±148)-(351±140) mmol/24 h vs (187±99) mmol/24 h] were significantly higher in postburn period and in sepsis as compared with those in normal controls. [WT5”HZ]Conclusion[WT5”BZ] There is a significant metabolicenhancement in early postburn period and in sepsis which was closely related to the posttraumatic systemic inflammatory responses, finely tuned by certain metabolic hormones and motivated by the enhancement of cellular metabolism of certain tissues. The animal model of burn and sepsis in sheep provides an ideal subject for the analysis of metabolic derangement in thermal injury and in sepsis. [WT5”HZ]