Expression Of Platelet-activating Factor In Necrotizing Enterocolitis And The Intervention Of Naloxone

ObjectiveTo explore the expression of platelet-activating factor (PAF) and its clinical significance in intestinal tissue with neonatal necrotizing enterocolitis (NEC). On that basis, the changes of platelet activation in NEC with naloxone (NX) intervention was observed to explore the role of anti-PAF drug in specific treatment for NEC.Methods1. The expression of PAF in 20 NEC necrotic intestinal tissue specimens were detected by immunohisto chemical study (using En Vision method).2.20 hospitalized infants with NEC and 19 control infants from October 2008 to December 2009 in The Tianjin Children's Hospital were enrolled in this study. The NEC infants were randomly divided into the NX group and the conventional group, the NX group was treated by routine therapy combined with NX, then the PAC-1 and CD62P were determined by Flow Cytometry (FCM) as markers for platelet activation before the treatment, treated in 4 days and 8 days, and compared with 19 control infants.Results1. Microscopic appearance of the normal intestine showed that the structure was complete, the villi arranged appropriately, the epithelial tissue was complete and continuous, and the glands were very regular. No abnormalities were seen in the normal intestine; While in the intestine with NEC, a large number villi fell off, even with the structure disappeared; The oedema could be seen in the submucosa and muscularis, the capillary was dilated and congestive; The damaged intestine was hemorrhagic, and friable; The necrosis were extended from villus to the submucosa, and often transmurally, with abundant infiltrated inflammatory cell, primarily neutrophils.2. Only weakly positive expression of PAF was seen in small amounts of mucosa and glands of normal intestine; While the strong positive expression of PAF in many areas of the necrotic intestinal tissue with NEC, including the bowel mucosa, glands, neutrophils and macrophages. The expression of PAF in NEC necrotic intestinal tissue (26.19±8.66) were significantly higher than the normal intestinal tissue (4.90±3.70)(P<0.05).3. (1) The positive expression percentage of PAC-1 and CD62P in the NEC infants before treatment were significantly higher than the control group (P<0.01). (2) As the treatment time prolonged, the positive percentage of PAC-1,CD62P in the NX group and routine group were significantly decreased. There were no significant difference when treated in 8 days compared with the control group (P>0.05). No significant difference of the two markers's expression were seen between the two groups in every time point (F=0.010,P＞0.05; F=0.747, P>0.05). There were no interaction effects between the time and the group (F=0.103, P>0.05; F=0.063, P>0.05). (3) The positive percentage of PAC-1 is positively related to CD62P (r=0.730, P<0.01).Conclusions1. The PAF plays an important role in the pathogenesis of NEC. It is involved in the pathophysiological process of NEC.2. Highly activated platelet is involved in the pathogenesis of NEC. Dynamic monitoring the platelet activation has an important clinical significance for the NEC diagnosis and illness change.3. No obvious effect is seen in platelet activation with NX intervention, further validation of the anti-PAF therapy in NEC is needed.