Changes in the expression of intercellular adhesion molecular 1 and interleukin-1 beta following spinal reperfusion injury

Lijun ZHAO; Hongqun LI; Qing SUN; Xiaoyu YANG; Yanguo QIN; Desheng DUAN

ABSTRACT

BACKGROUND:

At present, there are investigations on the expression of cytokines and adhesion molecular in ischemia-reperfusion injury at abroad,but they do not involve in the relative studies on endogenous cytokines and adhesion molecular on microvascular endothelial surface following injury.The expression of endogenous interleukin-1(IL-1) is limited only at mRNA level.

OBJECTIVE:

To prove into the mechanism of the expression of intercellular adhesion molecular 1 and its regulation factor IL-1 in spinal ischemia-reperfusion injury.

DESIGN:

A randomized grouping design, animal experiment.

SETTING:

Department of Sports Medicine, College of Physical Education Affiliated to Jilin UniversityMATERIALS This experiment was carried out at the Central Laboratory,China-Japan Union Hospital, Jilin University between March 2003 and January 2004. Totally 77 healthy male Wistar rats were randomly divided into normal control group (n=7), simple ischemia group (n=14) and ischemia-reperfusion group (n=56). Among the rats in the simple-ischemia group, 7 rats suffered from blood flow block for 30 minutes and 7 rats for 60 minutes; Rats in the ischemia-reperfusion group were assigned into 8 subgroups according to 8 time phases, respectively at reperfusion for 30,60 minutes, 2, 4, 6,9, 12 and 24 hours following spinal ischemia, with 7 rats at each time phase.

METHODS:

Spinal ischemia-reperfusion injury animal models were created with Zivin method. The expressions of vascular endothelial intercellular adhesion molecule-1 (ICAM-1) mRNA and IL-1β mRNA following spinal ischemia-reperfusion injury were detected with reverse transcriptionpolymerase chain reaction, immunohistochemistry and immunofluorescent confocal laser scanning microscope technique.MAIN OUTCOME

MEASURES:

The expression of IL-1β mRNA, activity of IL-1 polypeptide, expression of ICAM-1 mRNA and protein and activity of myeloperoxidase (MPO).RFSULTS Totally 77 animals were enrolled and all of them entered the stage of result analysis. ① The expression of IL-1β mRNA (A value)was significantly higher in the ischemia-reperfusion group than in the simple ischemia group and normal control group, with significant difference (respectively 1.07±0.33,0.60±0.22,0.57±0.12,t=3.751 7,11.852 6,P ＜ 0.01).② Activity of IL-1 polypeptide (A value )was significantly higher in the ischemia-reperfusion group than in the simple ischemia group and normal control group, with significant difference [respectively (33.7±3.2),(23.8±4.5), (23.1±2.1),t=2.798 8,9.962 7,P ＜ 0.01]. ③ ICAM-1 mRNA(A value)was significantly higher in ischemia-reperfusion group than in simple ischemia group and normal control group, with significant difference[respectively 0.94±0.12,0.52±0.11,0.51±0. 10,t=0.327 0,6.127 4, P＜0.01].④The expression of ICAM-1 protein was significantly higher at ischemiareperfusion for 4,6 and 12 hours than in simple ischemia group and normal control group, with significant difference [Respectively (316.90±26.00),(361.40±18.00),(406.00±23.00),(164.21±2.00),(180.00±32.00) μg/L,t=1.410 3,9.119 3 ,P ＜ 0.01]. ⑤ The activity of MPO was significantly higher at ischemia-reperfusion for 12 hours than in simple ischemia group and normal control group, with significant difference [respectively (15.00±2.00),(7.50±1.67),(6.67±1.00) nkat/g, t=3.012 2,P ＜ 0.01].

CONCLUSION:

Following reperfusion injury, inflammatory reaction in spinal cord is important molecular basis for causing blood spinal barrier impairment, and plays an important role in the process of secondary spinal cord injury.