The Mechanism And The Research Of Serum Proinflammatory Factor In Amniotic Fluid Embolism

AFE syndrome is an exceedingly rare and catastrophic complication of pregnancy that is related to the infusion of amniotic fluid into the maternal circulation. Because the onset of signs and symptoms is swift and with a high mortality , so when it happened, it always induce conflict. To date, the basic mechanism of this disease has not been consistent , it was first recognized by fetal material found in maternal pulmonary vasculature at autopsy. Recent studies have noted a striking similarity between AFE acid anaphylaxis, the clinical manifestations of AFE resemble an immediate allergic reaction, in accord with this new theory, further evidence supported the concept of AFE as an Anaphylactoid syndrome of pregnancy , as fetal antigens contained within the amniotic fluid gain entrance to the maternal bloodstream and endogenous mediators of inflammation may be released. The definitive diagnosis of this syndrome should be made on the basis of clinical presentation and excluding with reasonable certainty other diagnoses. In addition to the clinical findings, certain supportive laboratory tests may help to diagnose AFE, but there is no such a laboratory finding which by itself can either diagnose or exclude this syndrome, so it is urgent to standardize the diagnosis of AFE .Although fetal material such as Squames, lanugo hairs and meconium found within the maternal organ suggests the diagnosis and was a key feature in early descriptions of the disease , its absence in women who otherwise had clinical manifestations of AFE is problematic. Furthermore, squamous cells have been identified in blood in nonpregnant patients, so the finding of foetal elements in the maternal circulation can no longer be considered specific to AFE, a variety of medical indications have suggested that the detection of squamous cells in the maternal pulmonary artery circulation is a common finding, some amniotic fluid may routinely enter the venous circulation of many pregnant women.Many articles have recently appeared suggesting that amniotic fluid embolism may be the result of anaphylactic reactions to fetal antigens. The release of cellular mediators can explain many of the signs of AFE, in the light of this theory, immunological way using antibody to demonstrate the fetal antigens is thought to snore specific and sensitive. But there is no enough evidence thus far that anaphylaxis or mast cells are involved. Because of the characteristic of the clinical manifestations of AFE, it is difficult to obtain sufficient clinical data , and because of the limitation of methodology, it is so hard to find the true allergen, so the animal model and cell culture is more useful.Mast cells (MC) are one of important immunocyte , which can secret many bioactive substance , such as histamine, 5-HT, SRS-A and heparin . They have a pivotal role in allergic reactions and take part in many other pathophysiological conditions such as wound healing, fibrosis, tumors and autoimmune diseases. Tryptase and chymase , important and highly specific proteins in MC, are important markers to different of MC subtype , while basophils have little of them . Tryptase is a kind of serine proteases which can be found in many mammals. Compared with histamine , tryptase is a more selective marker of MC . Thus , tryptase are regarded as a characteristic marker of human MC presently. MC can produce many cell activating factors .Now we have found after the activation of MC , it can synthesize many proinflamation factors, such as TNF-α, IL-1, IL-8, GM-CSF and IFN-γ. Through these cytokines, MC take part in many pathophysiological conditions.This experiment study the distribution of MC when AFE occurred through the immunohistochemistry of tryptase and IL-8 staining of 10 mice of AFE with the amniotic fluid , 10 mice of AFE with meconium and 10 mice of solution with NaCl .The results are as follows:1 .HEMice of solution with NaCl : lung and intestinal mucosa are normal (picture 1,4). Mice of AFE (picture 2, 5) with the amniotic fluid: lung is congestion and edema, alveolar ectasia and the intervals collaped forming lung edema .The alveoli are filled with exudates. Bronchial muscosa is infiltrated by eosinophils. Lamina propria of intestinal mucosa is infiltrated by large number of eosinphils. Mice of AFE with meconium is more(picture 3,6).2.tryptaseMice of solution with NaCl (picture 7, 10, 13) : there is no positive cell in lung, intestinal mucosa and kidney. Mice of AFE with the amniotic fluid(picture 8,11,14): there are a lot of positive cells in lung , mainly around the vessels. There are a lot of positive cells on intestinal mucosa. There are also positive cell in other tissues, especially in distal convoluted tubule and proximal convoluted tubule. Mice of AFE with meconium is more(picture 9,12,15).3. TNF-αMice of solution with NaCl(picture 16) :the positive is weak . Mice of AFE with the amniotic fluid(picture 17): there is positive in lungs. Mice of AFE with meconium (picture 18):there is positive in lungs.4. IL-8Mice of solution with NaCl (picture 19, 22, 25) :the positive is weak. Mice of AFE with the amniotic fluid(picture 20,23,26): the smooth muscle cells of lung-bronchi are strong positive. The intestinal mucosa is also strong positive. Compared with first group, the different is significance. There is also positive in kidney. Mice of AFE with meconium is more(picture21,24,27).According to the study above, the conclusion is as follows:1. A large number of eosinophils in intestine,lung and other tissues indict anaphylactic reaction .2. Mice of AFE: MC is increased in the tissues, especially in lung and intestine.3. MC takes part in the pathophysiological conduction of AFE.4. tryptase can be selected to special mark MC, using this we can count the number of MC in tissues. 5. tryptase can be used to indict AFE in forensic medicine.6. TNF-αand IL - 8 take part in the pathophysiological condition of AFE.This experiment using immunohistochemistry to study the morphologic change of MC, confirm the function of tryptase,TNF-αand IL-8 in AFE . It provide exact theoretical base for the application of them in forsensic pathology.