| Objective Establishing the rats model of intermittent hypoxia, to study the chang es of cognitive function at different time of rats with intermittent hypoxia,Fas apo ptosis pathway related factors Caspase-8, FLIP and hippoocampal apoptosis, explor e the intervention mechanism of Fas apoptosis pathway effects on cognitive functi on in rats after hypoxia and the intervention effect of edaravone.Methods The selectioned 135 adult Wistar male rats, were freely divided into un handled control group(UC group), edaravone intervention group(ED group), intermit tent hypoxia group(IH group), then press3, 7, 14, 21, 28 d five time points. Each group divides into five subgroups which has 9 animal. IH group and ED group c yclic alternating give different nitrogen and compressed air flow rate per cycle 2m in, IH group and ED group box prompted the minimum oxygen concentration to5%, and then reply to 21%). The UC Group continued to air, The oxygen concen tration keep to 21%. In every period of time Morris water maze was used to Det erminate cognitive function after animal study, these rats were decapitated, the exp ression of FLIP and Caspase-8 were investigated by immunohistochemistry, Wester n blot assay,and the apoptosis of neurons was detected by the TUNEL method.Results 1 Morris water maze results: compared with group at different time: Rat s of IH group and ED group, the time of escape incubation period and through o riginal platform location were occurred at14 d, which started the animal from hypo xic exposure time is escape latencies and objective phenomenon across time is ob viously shortened, between rats of them in 14,21and28 d, the difference was obvio usly change(P<0.05), but 3d and 7d had no obviously difference(P>0.05); comp are the same point in time between each group: IH group and ED group, rats esc ape latencies and the target quadrant time is shortened in 14,21and28d(P<0.05); c ompared with IH group, ED group to find the target quadrant crossing time was significantly prolonged and the platform of time is shortened in 14,21and28d(P<0.05). 2 Rats of group Caspase8 results of each group by Western blot assay and i mmunohistochemistry: Compared with UC group, the expression of Caspase-8 in h ippocampal tissue of 3,7,14,21,28 d increased obviously in IH group(P<0.05); comp ared with IH group, the ED group expression of Caspase-8 at each time period re duced, but higher than the UC group(P<0.05). Expression of IH group and ED gr oup of Caspase-8 protein with the extension of hypoxia time has continued to inc rease, the highest 28 d, but in UC group no obviously change(P>0.05). 3 Rats of group FLIP results of each group rats by Western blot assay and immunohistoch emistry: Compared with UC group, IH group FLIP expression increased in 3, 7, 14, 21, 28 d at each time period of protein(P<0.05); compared with IH group, ED group at each time point of FLIP protein expression was obvious increased(P<0.05). The expression of FLIP protein in IH group and ED group with intermittent hypoxia prolonged decreases in reached peak at 14 d, then redused, but in UC gro up no obviously change(P>0.05). 4 The changes of rat hippocampal tissue cell ap optosis: The morphology of apoptotic cells were round or oval under light micros cope, nuclei showed brown or tan, which in irregular shapes, and nuclear of nonapoptotic cells were blue after countersstained using hematoxylin. Apoptotic cells c oncentrates mainly in the CAl area of hippocampus. Compared with UC group, I H group of 3,7,14,21,28 d at each time point hippocampal tissue cell apoptosis ind ex obviously increased(P<0.05); compared with IH group, the ED group at each ti me period of apoptosis index decreased significantly, but higher than the UC grou p(P<0.05). IH group and ED group cell apoptosis increased gradually as time pr olonged, arrivaled the peak in 28 d, but in UC group no obviously change(P>0.05).Conclusion 1 Expression of intermittent hypoxia activates the Fas death receptor pathway related protein Caspase-8 and FLIP protein, Fas death receptor pathway may play a certain role in nerve injury induced by IH. This may be sleep apnea / hypopnea syndrome is one of the pathophysiologic basis produces cognitive impairment syndrome patients. 2 Edaravone can reduce expression of apoptosis Caspase-8 and increase the expression of anti apoptosis of FLIP, thus resistance to nerve cell apoptosis because of IH and change the better of the rats’ learning and memory function which provide basis with medicine for the clinical therapy of OSAHS. |
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