脂多糖致炎时间对小鼠血液免疫与肠道组织形态的影响

Effects of Lipopolysaccharide Inflammation Time on Blood Immunity and Intestinal Morphology of Mice

本试验旨在通过给小鼠腹腔注射脂多糖(LPS),检测随着时间的推移小鼠血液细胞因子水平和肠道组织形态的变化。25只雄性ICR小鼠经腹腔注射LPS(5 mg/kg BW),在不同致炎时间[LPS注射前(0 h)以及注射后3、6、12、24、48和72 h]采血制备血清,通过酶联免疫吸附试验(ELISA)方法检测小鼠血清肠碱性磷酸酶(IAP)活性及炎性细胞因子肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1β、IL-4、IL-6和IL-8的水平;同时采集小鼠十二指肠、空肠、回肠和盲肠样品,苏木精-伊红(HE)染色制作组织切片,观察各肠段病理学变化,并测量各肠段绒毛高度(VH)和隐窝深度(CD),计算VH/CD(V/C)。结果显示:血清IAP活性,促炎细胞因子TNF-α、IL-6和IL-8以及抗炎细胞因子IL-4的水平在LPS注射后6 h时达到高峰,随后下降;而血清促炎细胞因子IL-1β的水平在LPS注射后6 h时略有升高,在注射后48 h时达高峰。与注射前(0 h)相比,LPS致炎小鼠在LPS注射后6 h肠道病理变化比较明显,小鼠肠黏膜损伤明显,上皮脱落、绒毛破裂、黏膜萎缩、水肿、且绒毛较短;随着时间的推移,肠黏膜在LPS注射后48 h时已开始缓慢恢复。与注射前(0 h)相比,LPS致炎小鼠十二指肠和空肠的V/C均在注射后6 h时出现显著或极显著下降(P<0.05或P<0.01),但在注射后72 h时已无显著差异(P>0.05)。由此得出,LPS(5 mg/kg BW)腹腔注射后6 h时小鼠血清促炎性细胞因子水平达到高峰,肠黏膜损伤明显,之后逐渐恢复正常。

This experiment was conducted to detect the changes in blood cytokine levels and intestinal tissue morphology of mice by intraperitoneal injection of lipopolysaccharide （LPS）. Twenty-five male ICR mice were intraperitoneally injected with LPS （5 mg/kg BW）, and the blood were sampled to prepare serum at different time points of inflammation [before LPS injection （0 h） and 3, 6, 12, 24, 48 and 72 h after injection]. The activity of intestinal alkaline phosphatase （IAP） and the levels of inflammatory cytokine, such as tumor necrosis factor-α （TNF-α）, interleukin （IL）-1β, IL-4, IL-6 and IL-8 in serum of mice were detected by enzyme-linked immunosorbent assay （ELISA） method. The samples of duodenum, jejunum, ileum and cecum were collected from the mice and hematoxylin-eosin （HE） staining was performed to observe the pathological changes of each intestinal segment. The villous height （VH） and crypt depth （CD） in each intestinal segment were measured and the VH/CD（V/C） was calculated. The results showed as follows： as time progressed, the activity of serum IAP and the levels of serum pro-inflammatory cytokines TNF-α, IL-6 and IL-8, and anti-inflammatory cytokines IL-4 peaked at 6 h after LPS injection, and then decreased continuously. The levels of IL-1β, a pro-inflammatory cytokine, increased slightly at 6 h after LPS injection and peaked at 48 h after injection. Compared with 0 h before LPS injection, the intestinal pathological changes of LPS-induced mice at 6 h after LPS injection were obvious. The mucous membranes of intestine were damaged, the epithelium was detached, the villus was broken, the mucous membranes were atrophic, edema, and the villus was short; over time, intestinal mucosa had slowly recovered at 48 h after LPS injection. Compared with 0 h before LPS injection, V/C in the duodenum and jejunum of LPS-inflamed mice were significantly decreased at 6 h after injection （ P 〈 0.05 or P 〈 0.01）; however, there was no significant difference at 72 h after injection （ P 〉0.05）. It is concluded that the levels of serum pro-inflammatory cytokines peaked at 6 h after intraperitoneal injection of LPS （ 5 mg/kg BW ）, intestinal mucosal damage is obvious, and gradually returns to normal afterwards.