| ObjectiveNecrotizing enterocolitis(NEC) is a severe emergency as well as the first causeof death in nneonate.In spite of extensive epidemiologic ,clinic ,and basicresearch ,there is not preventative treatment for this disease.To prove the protectiveeffects of rhubarb in neonatal rat model of necrotizing neterocoliyis, and to make sureweather the protection is related to the decrease of contents (platelet-activatingfactor) PAF and (tumor necrosis factor-α) TNF-αin intestinal tissue.Methods30 neonate Sprague-Dewley 48 hours olds rats(breastfeeding, either sex,weighing 5～10g) were divided into 3 groups. After rats in group A and B were madeinto NEC models by exposing them in hypoxia(100% N2) for 90 seconds and 4°Ccold for 10 minutes, twice a day during 3 consecutive days. Rats in group A workedas positive control were given rhubarb twice a day, while rats in group B worked asnegative control were given saline ,and rats in group C were not with NEC. On the5th day, all subjects were sacrificed and intestinal tissue were obtained to examine.The intestine nearly 1 cm around ileocecal junction was for histological analysis andscore, by formalin-fixed, paraffin-embedded, sliced and HE staining . According tothe lamina propria separation, neutrophil infiltration villi shed, necrosis, blood vessel dilation, interstitial edema, intestinal injury will be divided into 0 to 4 levels,histologic score≥2 identified as NEC. Remaining intestine used to detect thecontents of PAF, TNF-αin intestinal tissue by ELISA, and the contents wereexpressed pg per mg protein in intestinal tissue as (pg/mg pro). One way ANOVA,Brown-Forsythe, Kruskal-Wallis H tests, fisher exact test were used to analysisdifference among various groups, and Spearman correlation analysis were used toshow the relationship of PAF, TNF-αcontents in intestinal tissue and the extent ofintestinal damage.α=0.05 was considered statistical significance.ResultAfter induced by hypoxia and cold exposure several continual times, neonatalrats in groups A and B were activity decreased, unresponsive. Neonatal rats in groupB showed abdominal distension obviously, the activity decreased significantly , poorstimulated reaction, emaciated appearance, less subcutaneous fat and the skin fold inthe fifth day, while newborn rats in group A were diarrhea obviously, their activitiesand the appearance of the thin light than in group B, group C without diarrhea,activities, and subcutaneous fat fullness. Weight adding values of groups A, B, C were3.451±0.368, 2.103±0.404±0.206,4.429, and those values were significantlydifferent, F = 119.632, P <0.01. Gross inspection of intestine was observed thatintestines in group A were thin wall, with some small bubbles in the lumens, that ingroup B were easy fracture, hemorrhage, more small bubbles in lumens, and group Cwere normal. Intestinal mucosa necrosis , submucosa hemorrhage and muscle layerwere found in group B. As compared with group B, those histopathological injurieswere remarkably relieved after given rhubarb. The scores of histological evaluation ingroup A, Band C were 1.3±0.48,2.9±0.57,0.2±0.42, the score of histopatholigicalhad significant difference among groups, H=24.870, P<0.01.Compared with group B,the degree of injury in group A was decreased, but still higher than group C. The incidences of NEC in Group A and B were 30%(3/7),90%(9/1). The content of PAPin intestinal tissue in group A, Band C were 13520.98±2427.93,23021.14±2064.85,5628.21±1023.52, and the content of TNF-a were 29.23±4.73,42.30±3.65,16.00±5.02, there were significant difference among groups. The contents ofTNF-a,PAF in intestinal tissue in group A were much lower than group B.ConclusionsRhnbarb showed significant effects to prevent necrotizing enterocolitis in neonatal ratmodel, and meanwhile, it reduced hypoxia-induced intestinal injury, declined theinflammatory factors, had anti-apoptosis effect . The degree of injury in intestinaltissue after hypoxia were declined obviously when given rhbarb. Its mechanisms maybe related to decrease the contents of TNF-a,PAF in intestinal tissue ,which weretriggers of the inflammatory cascade reaction.
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