Histopathological and ultrastructural findings induced by heat-inactivated Lactobacillus plantarum and the culture supernatant on the intestinal mucosa of piglets: an ex vivo approach

ABSTRACT In the present study, histological, morphometrical and ultrastructural analysis were performed to investigate intestinal mucosa changes in piglets jejunal explants exposed to two concentration of heat-inactivated Lactobacillus plantarum and their respective culture supernatants. Jejunal explants were incubated for 4 hours in DMEM culture medium with a) only culture medium (control group), b) heat-inactivated Lactobacillus plantarum strain1 - LP1 (1.1 x 108CFU/ml), c) heat-inactivated Lactobacillus plantarum strain2 - LP2 (2.0 x 109CFU/ml), d) heat-inactivated Lactobacillus plantarum strain1 culture supernatant (CS1), and e) heat-inactivated Lactobacillus plantarum strain2 culture supernatant (CS2). Explants exposed to heat-inactivated L. plantarum strain 1 and 2 showed multifocal to difuse villi atrophy, villi apical necrosis and enterocyte flattening. Morphological assessment revealed similar results with bacterial adhesion to mucus and intestinal epithelial cells and, morphometric analysis showed a decreased villi height compared to the control group. Alterations in explants treated with the culture supernatant of both strains include mild villi atrophy and mild enterocyte apical necrosis. Morphological assesment reveled numerous well delineated villi and, morphometric analysis showed a significant increase in villi height compared to the control group. In general, exposure to the culture supernatants improved the intestinal morphology.

摘要 本研究通过组织学、形态计量学及超微结构分析，探究暴露于两种浓度的热灭活植物乳杆菌（Lactobacillus plantarum）及其对应培养上清液的仔猪空肠外植体的肠黏膜变化。将空肠外植体置于杜氏改良伊格尔培养基（DMEM）中孵育4小时，设置如下处理组：a) 仅添加培养液（对照组）；b) 热灭活植物乳杆菌菌株1-LP1（1.1×10⁸菌落形成单位每毫升）；c) 热灭活植物乳杆菌菌株2-LP2（2.0×10⁹菌落形成单位每毫升）；d) 热灭活植物乳杆菌菌株1培养上清液（CS1）；e) 热灭活植物乳杆菌菌株2培养上清液（CS2）。暴露于热灭活植物乳杆菌菌株1和2的外植体可见多灶性至弥漫性绒毛萎缩、绒毛顶端坏死及肠上皮细胞扁平化；形态学评估显示细菌黏附于黏液及肠上皮细胞的结果与此类似，形态计量分析则显示其绒毛高度较对照组降低。经两种菌株培养上清液处理的外植体病变表现为轻度绒毛萎缩及轻度肠上皮细胞顶端坏死，形态学评估可见大量边界清晰的绒毛，形态计量分析显示其绒毛高度较对照组显著升高。总体而言，暴露于培养上清液可改善肠道形态。