| Objective: Cerebral ischemia is the first leading cause of death and the most frequent cause of permanent disability in adults. The pathological mechanism for ischemic injury was a perplexing cascade reaction, including inflammation, oxidative stress and perturbation of calcium homeostasis, cytotoxic effect and reactive oxygen species/reactive nitrogen species (ROS/RNS). It is generally believed that excessive immunological reaction of and oxidative stress are two important pathophysiologic mechanisms which reside in necrosis and ischemic region, then result in brain injury. Therefore, it is a main measure to treat acute cerebral infarction by alleviating oxidative stress and inflammatory injury, however, anti-oxidant stress and anti-inflammation in combination have not reach the expected therapeutic effect. Developing anti-oxidant and anti-inflammation therapies in combination to combat ischemia-induced damage may bring progress in treatment of cerebral ischemia. are an effective lipid lowering medicine in clinical practice. Abundant of pharmacology and clinical research find that atorvastatin and probucol could elicit a vanity of biological effects through its anti-inflammatory and anti-oxidant properties respectively, but little is known regarding the synergetic effects and the mechanisms underlying of probucol and atorvastatin in combination on the brain parenchymatous tissue in cerebral ischemia in vivo. Prx2, Foxo3a and Nrf2 contribute to the pathophysiologic progress of cerebral ischemia, which play an important role in the damage of nerve cells. Our experiment observed the expressions of Prx2, Foxo3a and Nrf2 in rat model of focal cerebral ischemia; investigated the neuroprotective effects of probucol and atorvastatin in combination and its potential mechanisms. Methods: Male, healthy Sprague-Dawley rats were subjected to modified permanent middle cerebral artery occlusion (MCAO), as described by Longa previously. Experiment 1 was used to evaluate time course expression of Prx2 and Foxo3a after cerebral ischemia, including normal control group, 3 h, 6 h, 12 h, 24 h, 48 h and 72 h six time points. Experiment 2 was used to detect neuro-protection of probucol and atorvastatin in the acute phase of cerebral ischemia. Rats were randomly assigned to five groups: Sham operated group (Sham), MCAO group, Probucol group (MCAO + probucol 150 mg/kg), probucol and atorvastatin in combination group (MCAO + probucol 150 mg/kg + atorvastatin 10 mg/kg), atorvastatin group (MCAO + atorvastatin 10 mg/kg). The drugs was administrated by intraperitoneal injection according to different group after cerebral ischemia. At 24 h and 72 h after ischemia neurological deficit was evaluated, brain water content was measured by wet-dry method, infarct size were analyzed with 2, 3, 5- triphenyltetrazolium chloride (TTC) staining. Immunohistochemistry, reverse transcription–polymerase chain reaction (RT-PCR) and western blot were used to analyze the expression of Prx2, Foxo3a and Nrf2. Experiment 3 was used to detect influence of probucol and atorvastatin on blood brain barrier (BBB). Rats in this part were assigned to five groups as the same way of experiment 2. Confocal microscope was used to observe the extravascular IgG. Western blot was used to detect the expression of claudin-5.Results:1 After cerebral ischemia, the protein levels of Prx2 and Foxo3a were down-regulated beginning at 3 h, descending to the lowest values at 24 h after MCAO. But the mRNA levels of Prx2 and Foxo3a were down-regulated beginning at 3 h, descending to the lowest values at 48 h after MCAO.2 Rats in MCAO group, P group, A+P group and A group performed a right palsy. Compared with MCAO group, the scores in P group and A group were not lowered (P > 0.05). Although deficit scores in the combined treatment group were reduced, there were no significant differences in neurological deficit scores between the combined dose group and MCAO group (P > 0.05).3 In P group, A+P group and A group, the brain water content of ipsilateral hemispheres was reduced significantly compared with the MCAO group (P < 0.05). Moreover, the more striking decrease in the brain water content was observed for the combined treatment versus probucol or atorvastatin alone at 24 h (P < 0.05).4 Extensive lesion was developed in both striatum and lateral cortex in MCAO group. The combined treatment group significantly reduced the infarct volume after MCAO (P < 0.05). However, there was no significant difference in infarct volume between MACO group and P group or A group (P > 0.05).5 Probucol and the combined treatment upregulated the expression of Prx2, Foxo3a and Nrf2 after MCAO (P < 0.05). However, this reduction is not observed in A group.6 In sham operated group there was hardly any extravascular IgG in cortex. In MCAO group, P group and A group, a great deal of IgG leaked to brain tissue from cerebral circulation. Extravascular IgG were reduecd in the combined treatment group.7 Compared with sham operated group, MCAO induced sharply reduction of claudin-5 (P < 0.05). After treatment with probucol and atorvastatin in combination, the expression of claudin-5 in cerebral ischemia was significantly up-regulated (P < 0.05). However, the up-regulation of claudin-5 was not observed in P group or A group (P > 0.05).Conclusions: Probucol and atorvastatin in combination could contribute synergetic effect which can decrease neurologic impairment and tissue injury under cerebral ischemic conditions. This effect may be through up-regulation of Prx2, Foxo3a and Nrf2 expression, up-regulation of claudin-5 expression and reduction of extravascular IgG.
|
PDF Full Text Request