The Dynamic Changes Of Lymph Circulation In Burn Shock Stage: Lymphatic Motion, Cytokine, Endotoxin And Endothelium Ultrastructure

IntroductionA major burn injury results in hypovolemia induced burn shock, hypoxia. The acute post-burn period in the first 48h is marked by cardiovascular instability due to this hypovolemia from fluid shift and loss. The increasing levers of endotoxin and Tumor Necrosis Factor alpha (TNF-α ), Interleukin-6 (IL-6), IL-8 contribute to the development of subsequent immunosuppression, increased susceptibility to sepsis and multiple organ failure. The lymphatic system is critical to the maintenance of homeostasis of the circulatory system in that it returns critical amounts of extracellular fluid and macromolecular to the circulation daily. Thus, lymphatic vessels act as a primary route for fluid and plasma protein, which have filtrated through blood capillary walls to return to the blood circulation. Alterations in lymphatic activity play a critical role in determine lymph flow, hence impacting lymphatic function under both normal and pathophysidogical condition after thermal injury. Nevertheless, the definite molecularmechanisms have not been clearly elucidated both experimental and clinical. The levers of endotoxin and TNF- α ,IL-6,IL-8 in lymph circulation have not been clearly observed.The purpose of this study was to investigates the dynamic changes of endotoxin and TNF- α ,IL-6,IL-8 concentrations in lymph circulation during the acute period after a major burn injury. We hypothesized that there was a significant increase in lymph. Object:1,To study The dynamic changes of lymphatic motion and measure TNF- α ,IL-6, IL-8 levers in lymph of burn shock rats.2,To study the dynamic changes of endotoxin levers in lymph and plasma.3,To evaluate the method of study on lymphatic capillaries using the immunohitochemical double staining technique.4,To observe the ultrastructural changes of lymphatic endothelium. Methods:1, 42 male adult Wistar rats weighting between 250-300 g inflicted by 30% TBSA full-thickness scalding were employed as the model and were randomly divided into the burn resuscitation group (group A, n=18), the burn non- resuscitation group (group B. n=18) and the control (group C, n=6). Using inverted microscopy and digital image processing to observe the motive frequency (F) of the mesenteric lymphatic vessels and measure Ejection Fraction (EF), Pump Flow Index (PFI) in 48 hours post burn, and measure the speed of lymph and the concentrations of TNF- α , IL-6,IL-8 in lymph at 6,24,48 hours post burn.Lymphatic concentration of TNF- α , IL-6,IL-8 were measured by radioimmunoassay..2, After 6 female adult goats were inflicted with 30% TBSAfull-thickness skin burns, the speed of lymph flow and the lymphatic protein were measured. The concentrations of endotoxin in lymph and plasma were measured at 2,6,12,24,36,48 hours post burn. Lymphatic concentrations of LPS were determined by limulus amebocyte chromogenic assay test.3, An immunohistochemical double staining technique was utilized in skin and ileum using UEA - 1 in conjunction with a monoclonal antitype IV collagen anti - body to observe the lymphatic capillaries and blood capillaries.4, Mesentery lymphatic vessels were separated and fixed for examinations of scan electron microscopy.Results:1,In group A and B , the contractile frequency of the mesenteric lymphatic vessels were decreased, especially at 24h post burn(2.86±0.34 vs. 8.87±1.12,P<0.01) , and the same with the contractile indexes (EF, PFI) in 48 hours, despite the increasing lymph speed (P<0.01),and the levers of TNF-α ,IL-6,IL-8 in lymph were increased than group C(P<0.01) . The contractile frequency, the speed of lymph and the levers of TNF- a , IL-6,IL-8 in group A were significantly different with group B. The villi central lacteal of small intestine in group B were extremely dilated under microscope.2, The speed of lymph flow was increased, and the concentrations of total protein in lymph were increased, negatively correlated with those in plasma. The levers of endotoxin in lymph were increased, positively correlated with those in plasma.3, Single color was seen in lymphatic capillaries, and double colors were seen in blood capillaries.4,Ultrastructural disruptions such as swollen and contacts disruption oflymphatic endothelium after burns. ConclusionIn the burn shock stage, the motion of the lymphatic vessels were decreased and the levers of TNF- α , IL-6, IL-8 in lymph were increased. Fluid resuscitation could improve the lymph circulation. The increasing levers of endotoxin in lymph may cause the disorder of lymph circulation and endotoxemia. This immunohitochemical double staining technique could accurately differentiate lymphatic capillaries from blood capillaries and tissular space.