Effects Of 3,4-oxo-isopropylidene Shikimic Acid (ISA) On The Inflammatory Reaction In Rats Subjected To Middle Cerebral Artery Ischemia And Reperfusion And Its Probable Mechanisms

Effects of 3,4-oxo-isopropylidene shikimic acid (ISA) on the Inflammatory Reaction in Rats Subjected to Middle Cerebral Artery Ischemia and Reperfusion and its Probable Mechanisms Ischemic cerebral vascular disease (ICVD) is the first cause of death in China. Therefore, it is extremely necessary to probe into its pathophysiological mechanisms. In recent years, it is proved that inflammatory reaction plays an important role in ischemic damage, whose histological sign is leukocyte infiltration. It has been recognized that cytokines, adhesion molecules, inflammatory mediums, transcription factors and leukocyte infiltration are associated with ICVD and related intimately to one another, which is so-called inflammatory reaction cascade. 3, 4-oxo-isopropylidene-shikimic acid (ISA) is one of synthetic derivatives of shikimic acid (SA) which was a component extracted from Illicium verum. The previous research has proved that SA has the anti-inflammation and analgesic effects. ISA can inhibit experimental thrombosis and platelet aggregation significantly. In vitro ISA can inhibit human umbilical vein endothelial cell (HUVEC) and neutrophil adhesiveness induced by H2O2 and HUVEC and leucocyte adhesiveness activated by TNF-α. In this paper, by the means of biochemical assay, radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) and molecular biology, effects of ISA on the inflammatory reaction in rats with transient middle cerebral artery occlusion (tMCAO) and probable mechanisms were studied from blood brain barrier (BBB) damage, cerebral edema, leukocyte infiltrate, cytokines expression, adhesion molecules expression, cyclooxygenase-2 expression and transcription factors activation. The chief results are as follows. 1 Protective effects of ISA on neurons in rats with tMCAO OBJECTIVE: To study the effects of ISA on nerve symptoms, infarction size, content of neuron-specific enolase (NSE) and morphological changes. METHODS: The tMCAO model was made according to Koizumi (1986) and Nagasawa (1989). The rats were subjected to MCAO for 3 hours, and then nerve symptoms were scored at different time-points (ischemia 3 hours, reperfusion 3 hours and reperfusion 21 hours). After 21 hours of reperfusion, the content of NSE in serum was assayed by RIA, and TTC staining of brains was made to determine the size of cerebral infarction. HE staining of brains was also performanced to observe morphological changes. RESULTS: After tMCAO, in the vehicle group, nerve symptoms, the size of cerebral infarction as well as the content of NSE rose greatly, ISA 200 mg/kg and ISA 100 mg/kg decreased significantly them (P<0.05 or 0.01). In the vehicle group, a number of neurons appeared degeneration, necrosis or disappearance, with tissue edema and leukocyte infiltration. In ISA 200 mg/kg group, the status was improved. CONCLUSION: ISA can relieve neuronal ischemic damage. 2 Intervention effects of ISA on inflammatory reaction in rats with tMCAO OBJECTIVE: To observe the effects of ISA on BBB damage, cerebral edema and leukocyte infiltrate. METHODS: The permeability test of Evans blue (EB) was determined after ischemia 3 hours and reperfusion 3 hours in rats with tMCAO. The content of water and the activity of myeloperoxidase (MPO) in brain as well as IHC staining of matrix metalloproteinase-9 (MMP-9) were assayed at 21 hours of reperfusion. RESULTS: After tMCAO, the cerebral microvessels can be permeated through by Evans blue and IgG, and MMP-9 expressed on them at in quantities. The content of water and the activity of MPO in brain increased obviously. ISA can observably decrease the content of water and Evans blue, reduce the expression of MMP-9 and the activity of MPO (P<0.05 or 0.01, compared with the vehicle group). CONCLUSION: ISA can relieve the inflammatory reaction leaded to by cerebral ischemia and reperfusion. 3 Effects of ISA on the adhesion molecules expression in rats with tMCAO OBJECTIVE: To examine the effects of ISA on the expression of intercellular adhesion molecule-1 (ICAM-1), lymphocyt...