The Changes And Its Significance Of BFGF And GFAP In Rats After Acute Spinal Cord Injury

The changes and its significance of bFGF aid GFAPin rats after acute spinal cord injuryiPostgradute: Zhang Wei-HongSupervisor: Wang Dao-XinFirst Affiliated Hosptial of Nanjing Medical UniversityAbstractsObjective:To study the changes and relationship between basic fibroblast growth factor (bFGF) and glial fibrillary acidic protein (GFAP) in spinal cord after experimental spinal cord injury, and discuss the self-protective mechanism and the function of astrocytes in injured spinal cord.Method:Twenty -five SD rats with an average 250 grams weight were randomly divided into five groups: the group of 1 day after SCJ, the group of 4 day after SCI, the group of 7 day after SCI, the group of 14 day after SCI and control group; each group has 5 rats. We adopted Allen?s weight-drop (WD) technique with 25Ograrns (1 Og X 2.Scm)force onto the exposed dura at T8 to make rats acute spinal cord injury . All the rats injured groups were killed at the end of 1 St 4th th and 1 4th day after SCI, and two piece of 0.3-0.5cm tiusse parted from injured position were taken out to make paraffin-embedded specimens after 10% formalin fixation for 24h; the tissue of control group was taken out at the corresponded position at the same time. Immunohistochemical and histological staining techniques were used to evaluate the lever of GFAP and bFGF in spinal cord after acute spinal cord injury, and the staining was quantitated by imagine analysis technique, and with the assistance of light microscope to observe the state of hypertrophy and hyperplasia of astrocytes. The neurological function of spinal cord was graded3according to Gale combined behavioral score (CBS).Rcsults:(l ) In normal spinal cord of SD rats there expressed small quantity bFGFin the cytoplasm nuclei of astrocytes and some motor neurons ofanterior hom. Compared with control group the expression of bFGF... tin inJured spina1 cord existed significant difference (P<0.001). 1 dayafter SCI its expression increased prominently, and peaked at 7tl,day,and at the end of l4th began drop.(2) In normal spinal cord GFAP exited in cytoplasm of astrocytes; its.. lexPression was increased progressive1y from 1,, to l4',' day (P<0.05)after SCI.(3) From 1 st to 7tl1 day after SCI the change ofastrocytes was hypelPlasia,and at the end of l4,h the astrocytes showed hyperPlasia andhypertrophy.(4) The expression lever of GFAP was negative correlated with thedegree of SCI according as Gale combined behavioral score,(r=-0.775, P=0.000), however bFGF was not correlated with CBS(rv-0.294, P==0.208). The expression of bFGF was positive correlatedwith that of GFAP (r=0.777, P=0.000).ConcIusions:(l) The expression of bFGF increased in astrocytes and neurons was oneof the ear1y responses of SCI, and it might play an important role inkeepping neurons live and differentiation, and in extending neuraxon.(2) Reactive astrogliosis showed asterocytes hypertrophy and hyperPlasia,and it was important to improve 1ocal surrounding of nerve repaiY, atthe early period of SCI, but glial scar made by reactive astrogliosiscould hinder neuraxon regeneration and remyelination the late periodof SCI.(3) Reactive astrogliosis astrocytes caused by SCI effected neural4self-repairing and regeneration of spinal cord, so it suggested that there was a self-protective mechanism in spinal cord itself.(4)The expression lever of GFAP might act as one of indexes to evaluate the degree of SCI.