Expression and significance of glial fibrillry acidic protein in the plerosis of brachial plexus injury

Abstract

Aim: To observe the expression of glial fibrillry acidic protein (GFAP) in the plerosis of brachial plexus injury and probe into its significance. Methods: The experiment was conducted in the Staff Room of Anatomy, Zhongshan Medical College, Sun Yat-sen University from September 2004 to March 2005. Sixty-five male adult SD rats were randomly divided into control group (n=5) and experimental group (n=60). Rats in the experimental group were made into three kinds of brachial plexus injury models: Right C 7 anterior root avulsion group (group A), C 7 anterior root avulsion with right C 5-T 1 posterior roots breaking group (group B), right C 7 anterior root avulsion with hemi-transect between C 5 and C 6 segment of spinal cord group (group C). Nerve anesthesia symptoms were assayed with combined behavioral score at the 1st, 3rd, 7th, 14th, days postoperatively. Immunohistochemical method and image analysis were used to observe the expression of GFAP in astrocytes of spinal cord in C 7 section. Results: Of 65 included rats in the experiment, one rats in the C 3 group of experimental group died 12 days after operation, and 64 rats were involved in the analysis of results. 1 Expression of GFAP in astrocytes after brachial plexus injury: Group A < group B < group C, and it was higher in these. 3 groups than that in the control group (Group A at the 1st, 3rd, 7th, 14th days were 141.5±2.1, 150.1°6.4, 158.4±5.0, 169.3±1.6 respectively; Group B were 156.7±1.9, 160.2±1.9, 172.5±3.5,190.1±3.2 respectively; Group C were 162.7±5.1, 183.3±1.7, 191.2±3.7, 228.7±4.2 respectively; Control group were 127.6±2.19, 127.6±2.19, 127.6±2.19, 127.6±2.19 respectively;P < 0.01). 2 Combined behavior score of each injured group showed a decreasing tendency from the 1st to the 14th day. 3 Expressions of GFAP in groups A, B, C were negatively correlated with combined behavior score of corresponding group (r=-0.956to-0.993, P < 0.01). Conclusion: The expression of GFAP induced by brachial plexus injury is increased progressively, which indicates that astrocytes take part in the whole process of nerve injury and repair.