PSD 95 and NMDAR Alteration as Plasticity Responses After Intermittent Hypobaric Hypoxia Induction in Sprague-Dawley Rats

Introduction: Intermittent hypobaric hypoxia (IHH) is believed to have neuroprotective effect. IHH induces changes in gene expression and intracellular signaling pathways that lead to the emergence of intracellular adaptation through the process of erythropoiesis, angiogenesis, glucose transport and anaerobic glycolysis through HIF-1 alpha gene activity. IHH induction decreases brain cortical tissue damage, and increases microvascular density. The aim of this study is to investigate whether preconditioning by intermittent hypoxia in a hypobaric chamber influences plasticity responses in rat brain tissue. PSD 95 is required for synaptic plasticity associated with NMDA receptor signaling. Method: A total of 25 Sprague-Dawley rats were divided into 4 groups of IHH and 1 group as control. The 4 IHH groups were exposed to intermittent hypobaric hypoxia in Indonesian Air Force Institute of Aviation Medicine hypobaric chamber, by 1 week interval for 4 times (day-1, 8, 15 and 22). The brain was taken for measuring PSD 95 using ELISA technique and expression of NMDAR using immunohistochemistry. Results: The group treated with 1, 2, 3, 4 times exposure to hypobaric hypoxia shows significant alteration in NMDAR expression, but there is no significant differences in PSD 95 compare to control group (p > 0.05). Conclusion: IHH shows plasticity responses after IHH induction in Sprague-Dawley rats brain.