| Background Ischemic cerebrovascular disease was seriously harmful to human health because of its high morbidity, high mortality and high incidence. Minocycline played a neuroprotective role. The present study had confirmed that it played the role through the inhibition of matrix metalloproteinase expression, product of nitric oxide class, generated free radicals waterfall effect and other mechanisms; However, it was not been reported at home and abroad that Minocycline played the neuroprotective role through the alteration of the expression of GFAP and Glutamate.Objectives To investigate the infarct volume,expressions of GFAP, Glu in rats’ brain tissues of ischemia-reperfusion and the intervention effect of minocycline and to probe into the mechanisms of cerebral protection of minocycline.Methods120healthy male Sprague-Dawley rats, weighting250-300g, were randomly divided into4groups:normal group(N), sham-operated group(F), ischemia-reperfusion group(IR) and schemia-reperfusion minocycline treatment group(M). Then all of the groups were further divided into4subgroups according to reperfusion time interval of6,12,24,48h after2h brain ischemia; All of the12h groups had12rats,6for immunohistochemistry image analysis,6for TTC staining, other subgroups with6rats. Minocycline of45mg/kg were delivered by gavage to rats of M group at reperfusion after2h ischemia, then every12hours administered the additional22.5mg/kg. Same doses of saline were administered to rats of N group and F group. The left focal cerebral ischemia by MCAO was induced according to thread embolism method. After model was established, neurological deficit score was obtained of each groups of rats.6rats were randomly selected from each12h group, full fresh brain tissues of each were removed and used for TTC staining. The rest brains were removed in the corresponding time points, after being routinely dehydration, embedded in paraffin, serial sections were obtained before and after the optic chiasm about2mm. Observed the infarction morphology change through HE staining and the expression of GFAP and Glu with immunohistochemistry technique.Results1Nerve defect symptoms and neurological deficit scoreThe neurological functional deficit was not seen in normal group and sham-operated group. However there were varying degrees of right hemiplegia in M group and IR group. Neurological deficit score from rats of ischemia-reperfusion minocycline treatment group was lower than the ischemia-reperfusion group at the same time. The difference was significant(P<0.05).2TTC dyeingThere was no obvious infarction in rats’brain tissues of sham-operated group and normal group with TTC stained. However, there was obvious infarction in rats’brain tissues of M group and IR group. The infarct volume of ischemia-reperfusion minocycline treatment group was smaller than that of ischemia-reperfusion group at the same time. The difference was significant(P<0.05).3HE stainingThe rats’brain tissues of normal group and sham-operated group were normal. The structure of brain cell was clear; The number of normal neurons was large; And there were not necrotic cells. The brain tissues of ischemic penumbra of ischemia-reperfusion group, observed from high power microscope, were lightly stained because of the neuronal degeneration or necrosis and the reduced number of nerve cells. Normal neurons in ischemic penumbra of ischemia-reperfusion minocycline treatment group were increased than that in ischemia-reperfusion group.4Immunohistochemical stainingThere were lowly expressed of GFAP and Glu in brain tissues of normal group and sham-operated group. But there were highly expressed in brain tissues around the infarct of ischemia-reperfusion group and ischemia-reperfusion minocycline treatment group. Studying showed that the expression of GFAP and Glu were decreased in brain tissues of ischemia-reperfusion minocycline treatment group than those in ischemia-reperfusion group. The difference was significant(P<0.05).Conclusions1When rats of model were intervenced by the certain amount of minocycline in the early states after ischemia-reperfusion, neurological deficit score was decreased, infarct volume and neuronal necrosis was reduced, indicating that minocycline had a protective effect.2GFAP and Glu were highly expressed after ischemia-reperfusion, the expression of GFAP and Glu were decreased in infarction areas when minocycline was administered. Minocycline played a neuroprotective role, probably by inhibiting the expression of GFAP and Glu. |
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