Induction of Necrotizing Enterocolitis in Non-Premature Sprague-Dawley Rats and the Effect of Administering Breast Milk-Isolated <i>Lactobacillus salivarius</i> LPLM-O1

Abstract

Due to an increasing incidence of necrotizing enterocolitis (NEC), as well as its associated mortality and long-term complications seen in surviving patients, the main focus of research in NEC has shifted to the prevention and treatment of the disease. The hypothesis of this work is that the strain Lactobacillus salivarius LPLM-O1 can decrease the intestinal injuries in a model of induced NEC. 26 newborn Sprague-Dawley pups were used in this study and randomized in three groups: control group (n = 6), which were fed with infant formula (Similac Neosure TM , Abbott); probiotic group (n = 10), which were fed with the same infant formula but fortified with 109 colony-forming units (CFU) of Lactobacillus salivarius LPLM-O1, and the NEC-induced group (n = 10). Each group was fed with 100 μl of food formula every three hours, using a modified syringe. The probiotic and NEC groups were exposed to asphyxia- and cold-induced stress to develop experimental NEC. At the end of the experiment (96 hrs), animals were sacrificed, and their small intestines were carefully removed and evaluated for typical signs of NEC, microbiological count and histological analyses. The histological analysis of the NEC-induced group showed transmural necrosis (grade 4); in the probiotic group, the grade was comparatively lower (grade 2). Survival ratewas higher in the probiotic group (83%) than in the NEC-induced group (46%); however, the difference in not statistically significant (p = 0.14). Lactic acid bacteria counts were higher in the probiotic group than in the NEC-induced group (8.4 × 108 and 6.1 × 107 CFU/intestine tissue gram, respectively). According to these results, the model of artificial induction of NEC was effectively establishedin all pups, and the probiotic strain slightly decreases the injuries’ grade in newborn pups.