Whole Body Hypoxic Preconditioning On GFAP/NEUN Expression In Rats With Cerebral Ischemia-reperfusion

ObjectiveIschemic cerebrovascular disease characterized by high mortality and high mutilation, is one of the main reason that seriously endangers human health. Hypoxia or ischemia preconditioning considered an endogenous strongest neural protection phenomenon. But it is a kind of injury adaptability. Hypoxia or ischemia preconditioning has never progressed to detailed clinical practice. Because this was largely due inducing preconditioning ischemia in vital organs, such as the heart or brain, that would lead to myocardial infarction or stroke.Whole body hypoxic preconditioning (WHPC) is a major breakthrough of the application of preconditioning. It was proved that also has the organ protection. In application process, it has the following advantages:less danger and easier to control. Hemodynamics was caused serious influence in the process of implementation of WHPC, human being cannot tolerate when fully conscious, So it has become inevitable that application WHPC under general anesthesia.Astrocytes (AST), to participate in the formation of cytoskeleton, guide neuronal migration, promote the neuron survival and differentiate in the development of nervous system, support neuron function with nutrients and protective buffering, secrete numerous neurotrophic factors and growth factors, adjusts ions balance of internal and external cells, have a wide range of connection with nearby neurons. In recent years, studies substantiate that AST can be increased and activated repeatedly in pathologic state. It can protect neurons; promote its repair and rebirth in the early times. But the late, because of scarring hyperplasia by activation of glial cells. It will against the repair of neurons, even can cause further damage.This study was to explore the influence that Propofol combine with whole body hypoxic preconditioning on GFAP expression in rats with cerebral ischemia reperfusion; the mechanisms of WHPC effects of cerebral ischemia reperfusion disease. Provide some new referencesMethods1. Rat choice and group:130adult male SD rat, weight180-250g, randomly divided into ischemia reperfusion group (IR group, n=40); Hypoxic preconditioning group (WHPC group, n=40); Propofol with hypoxic preconditioning group (WHPC+P group, n=40); sham operation group (Sham group, n=10)2. Animal model evaluation:At1,3,7,14,21d after ischemia reperfusion injury, The behavioral score was tested. HE staining was used to study the pathological changes at ischemic core and the boundary zone3. Hypoxic preconditioning:Homemade normal atmosphere and hypoxic organic glass box, size100cm*80cm*60cm. Set the intake, outlet, and the testing port of the gas concentration, on both sides of the body with a small fans, to blending the gas. Put five rats into the box maximumly each time. The intake linked with nitrogen, Begins timer when the oxygen concentration dropped to8%, after3h, open the hypoxic organic glass box; allow free access to food and water, make MCAO model after24h.4. Middle cerebral artery occlusion reperfusion (MCAO/R) model:Rats in IR/WHPC/P+WHPC group were made MCAO/R model by Zea Longa [1] method. Rat in sham operation group were operated, but not insert monofilament nylon thread.5. GFAP, NEUN were detected:Rats in IR/WHPC/P+WHPC/sham group were detected the expression of GFAP/NEUN in the ischemic core and the boundary zone by immunohistochemistry technique in different point.6. Learning and memory test:Male SD rats were divided randomized IR/WHPC/P+WHPC/sham group. Rats were trained5days by Morris water maze before take organizations in the7d,14d and21d. Respectively processed cruise positioning test and space exploration test. Recorded escape latency and the times of through platform.Results1. No significant differences were found in the rat age, gender and weight (P>0.05)。2. In the ischemic core, Compared with sham group, the results of immunohistochemical were showed that the expression of GFAP was increased at1d,3d after MOCA (P<0.05). Compared with IR group, the expression of GFAP in WHPC/P+WHPC group were significantly increased (P<0.05). No statistically significant difference between the WHPC group and P+WHPC group (P>0.05). Compared with sham group the expression of GFAP in IR/WHPC/P+WHPC group was marked decreased at7d,14d after MOCA(P<0.05), no statistically significant difference between the sham group, WHPC group and P+WHPC group(P>0.05).3. In the boundary zone, compared with sham group, the expression of GFAP were significantly increased at Id,3d,7d,14d,21d after MOCA (P<0.05). WHPC/P+WHPC group expressed more GFAP than IR group at ld,3d,7d after MCAO (P<0.05). WHPC/P+WHPC group got the top at3d, and IR group at7d, WHPC/P+WHPC group reach the top earlier than IR group.4. in the ischemic core and the boundary zone, IR/WHPC/P+WHPC group’s NEUN expressed less than sham group(P<0.05), Compared with IR group, the expression of NEUN in WHPC/P+WHPC group were significantly increased(P<0.05).5. IR/WHPC/P+WHPC group’s escape latency were more than sham group (P<0.05), Compared with IR group, the escape latency in WHPC/P+WHPC group were significantly decreased (P<0.05).Conclusion1. WHPC can make astroglia proliferative and activated; make the expression of GFAP increased quantity, the peak in advance. Therefore, protect neurons in the early ischemia, promote neurons regenerate and repair.2. Protection neurons of focal cerebral ischemia reperfusion injury can be induced by WHPC. The expression of NEUN was more than IR group. WHPC is beneficial to the recovery of neurobehavioral and learning and memory capacity.3. WHPC combined application of propofol has no significant impact on the protection of ischemia-reperfusion injury.