Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Hunan Research Center of Livestock and Poultry Sciences, South Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
University of Chinese Academy of Sciences, Beijing, 100008, China.
Sci China Life Sci. 2024 Feb;67(2):379-390. doi: 10.1007/s11427-022-2391-x. Epub 2023 Oct 9.
Weaning piglets usually suffer from severe diarrhea (commonly known as postweaning diarrhea, PWD) along with intestinal motility disorder. Intestinal peristalsis is mainly regulated by the longitudinal muscle-myenteric plexus (LM-MP). To understand the relationship between intestinal LM-MP function and the development of PWD, we compared the intestinal electrical activity, and the transcriptional profile of the LM-MP between 21-day-old piglets (just weaned, n=7) and 24-day-old piglets (suffered the most severe weaning stress, n=7). The results showed that 24-day-old piglets exhibited different degrees of diarrhea. A significant increase in the slow-wave frequency in the ileum and colon was observed in 24-day-old piglets, while c-kit expression in the intestinal LM-MPs was significantly decreased, indicating that PWD caused by elevated slow-wave frequency may be associated with loss of c-kit. The real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) showed that intestinal LM-MPs in 24-day-old piglets may undergo inflammation and oxidative stress. Significant increases in 8-hydroxy-2'-deoxyguanosine and decreases in thioredoxin suggest that weaning may lead to DNA damage in the LM-MP of 24-day-old piglets. In addition, activating transcription factor 3 was significantly upregulated, indicating nerve damage in the LM-MP of 24-day-old piglets. The transcriptomic results showed that most of the differentially expressed genes in the ileal LM-MP after weaning were downregulated and closely related to the cell cycle process. Subsequent RT-qPCR analysis showed that the relative expression of p21 was upregulated, while the expression of cyclin A2, cyclin B1, and proliferating cell nuclear antigen was downregulated in the ileal and colonic LM-MP of 24-day-old piglets, suggesting that weaning may inhibit cell proliferation and cause G1/S cell cycle arrest in ileal and colonic LM-MP. In conclusion, weaning may lead to cell cycle arrest by causing DNA damage in the LM-MP, impairing intestinal motility regulation, and ultimately leading to diarrhea in piglets.
断奶仔猪通常会遭受严重的腹泻（通常称为断奶后腹泻，PWD）以及肠道蠕动障碍。肠道蠕动主要由纵行肌-肌间神经丛（LM-MP）调节。为了了解肠道 LM-MP 功能与 PWD 发展之间的关系，我们比较了 21 日龄仔猪（刚断奶，n=7）和 24 日龄仔猪（断奶应激最严重，n=7）之间的肠道电活动和 LM-MP 的转录谱。结果显示，24 日龄仔猪出现不同程度的腹泻。与 21 日龄仔猪相比，24 日龄仔猪回肠和结肠慢波频率显著增加，而肠道 LM-MP 中的 c-kit 表达显著降低，表明由慢波频率升高引起的 PWD 可能与 c-kit 丢失有关。实时定量 PCR（RT-qPCR）和酶联免疫吸附测定（ELISA）显示，24 日龄仔猪的肠道 LM-MP 可能发生炎症和氧化应激。8-羟基-2'-脱氧鸟苷的显著增加和硫氧还蛋白的减少表明，断奶可能导致 24 日龄仔猪 LM-MP 的 DNA 损伤。此外，激活转录因子 3 显著上调，表明 24 日龄仔猪 LM-MP 的神经损伤。转录组学结果表明，断奶后回肠 LM-MP 中大多数差异表达基因下调，与细胞周期过程密切相关。随后的 RT-qPCR 分析显示，24 日龄仔猪回肠和结肠 LM-MP 中 p21 的相对表达上调，而 cyclin A2、cyclin B1 和增殖细胞核抗原的表达下调，表明断奶可能抑制细胞增殖并导致回肠和结肠 LM-MP 中的 G1/S 细胞周期停滞。综上所述，断奶可能通过导致 LM-MP 中的 DNA 损伤，损害肠道蠕动调节，从而导致仔猪腹泻，引起细胞周期停滞。
