Count and role of Paneth cells in neonatal necrotizing enterocolitis

Abstract

Objective To detect the number of Paneth cells in necrotizing enterocolitis (NEC), to explore the changes of secreted antimicrobial peptides and to elucidate the role of Paneth cells in NEC. Methods From January 2015 to June 2018, 12 cases of intestinal tube specimens were collected from NEC children. For control group, there were intestinal volvulus (n=2), Meckel's diverticulum (n=2) and small intestine atresia (n=6). All samples were harvested from leading edge or marginal zone of surgical samples for preventing collecting necrotic tissue. Paneth cell was counted by AB/PAS staining and immunohistochemistry. The expressions of Paneth cell antibacterial peptides (lysozyme, α-defensin 5 & secretory phospholipase A2)were detected by immunohistochemistry and Western blot. Quantitative polymerase chain reaction (qPCR) was employed for detecting the RNA expressions of inflammatory factors and antibacterial peptides. The average value of optical density was measured by Image-J software. Mean was analyzed by t test and statistical analysis was performed by SPSS 22.0 software. Results Goblet and Paneth cells were lightly stained and counts decreased. And lysozyme, α-defensin 5 and secretory phospholipase A2 proteins were predominantly expressed in the bottom of small intestine crypt and brown in cytoplasm of Paneth cells. As compared with control group (average optical density values: 0.45±0.06, 0.75±0.03 & 0.66±0.04), lysozyme, α-defensin 5, secretory phospholipase A2 decreased in NEC group (average optical density values: 0.05±0.02, 0.22±0.04 & 0.25±0.03) and the differences were statistically significant (P<0.05). As compared with control group (expression intensity: 0.58±0.14, 0.76±0.05 & 0.83±0.09), the expressions of lysozyme, alpha-defensin 5 and secretory phospholipase A2 decreased in NEC group (expression intensity: 0.30±0.08, 0.46±0.07 & 0.53±0.03) and the differences were statistically significant (P<0.05). The number of Paneth cells was lower in intestinal specimens of NEC children than that of control group. In control and NEC group, their counting scores were respectively 2.8±0.29, 2.5±0.27 and 2.7±0.26 and 0.67±0.19, 0.7±0.26 and 0.5±0.15 . The differences were statistically significant (P<0.05). As compared with control group, the inflammatory factors TNF-α and IL-6 mRNA showed a rising trend in NEC group and the difference was statistically significant (P<0.05). Lysozyme, α-defensin 5 and secretory phospholipase A2 mRNA decreased in NEC group as compared with control group and the difference was statistically significant (P<0.05). Conclusions The number of Paneth cells and contents of antimicrobial peptides are lower in intestinal tissues of NEC children than those in control group. Key words: Paneth cells; Enterocolitis; Neonate; Necrotizing