| Objective: To observe the impact of Obstructive sleep apnea syndrome(OSAS) on spatial learning and memory ability in rats, measure the hippocampus volume and detect in the Tau protein Phosphorylation level in OSAS hippocampus neurons in rats, to further explore the mechanism of OSAS.Materials and methods: The 30 male SD rats were randomly divided into OSAS model group and blank control group, with 15 rats in each group. Hierarchical model group rats were injected into the sodium hyaluronategel of different month age(3 months, 6 months, 9 months of age) in the model group rats pharyngeal cavity parts, creating OSAS model, further observations made after the model rats, determination of 12 month old rat model was made successfully. At the same time, through the Morris water maze test of two groups of rats with spatial learning and memory ability of change; on this basis, using MRI scanning technique for the measurement of the two groups of rats brain and bilateral hippocampus volume change; finally, using immunohistochemistry method to detect the two groups of rats thr231, ser396 site of tau protein phosphorylation level in hippocampus neural cells, and analyze the difference.Results:The OSAS rat model was successful: the average sleep oxygen saturation, the lowest oxygen saturation of OSAS model rats were significantly decreased compared with the previous model, and the apnea index increased significantly. Navigation water maze test results show that in the blank control group rats escape latency were the first day(31.9 + 18.3) s, the second day(21.8 + 12.2) s, the third day(1.37 + 3.1) s, the forth day(7.1 + 4.2) s; obstructive sleep apnea syndrome(OSAS) model group rats escape latency were the first day(41.2 + 17.7) s, the second day(30.6 + 14.5) s, the third day(3.28 + 16.7) s, the forth day(21.4 + 9.8) s; Obstructive sleep apnea syndrome(OSAS) in the model group compared with blank control group rats escape latency, the two groups were statistically significant(P < 0.05). Spatial probe test and the test results show that, the blank control group rats crossing the platform number for(5.9 + 2.3), model group OSAS for(3.1 + 0.8), model group compared with the control group rats through the platform of the reduction in the number, two groups has significant difference(P < 0.05). MRI results show that compared with the control group, after modeling the total volume of rats with left hippocampus volume, right hippocampus volume and standardization of hippocampus were reduced, of which the left side is more obvious, the degree of reduction were 25%, 22.4% and 24.7%. Immunohistochemical assay showed that phosphorylation levels of two groups of rats with bilateral hippocampus nerve cell tau protein(Thr231, Ser396 site), under the light microscope, observed in control group of hippocampus nerve cell envelope and axonal staining less number and light color: Thr231 for(5.8+2.0), Ser396 for(2.0+0.5), OSAS model group hippocampus nerve cell envelope and axonal staining number and deep color Thr231 for(30.9+7.6), Ser396(23.4+6.2), and the blank control group rats were compared, OSAS model group hippocampus neural cells phosphate level increased significantly.Conclusion:OSAS can decrease the space learning-memory ability of rats, and its mechanism possibly related to decrease the volume of the hippocampus and increase the expression of Tau protein Hyperphosphorylation in Hippocampus Neurons in Rats. |
