ABSTRACT
Objective To investigate the neuroprotective action of astragaloside Ⅳ (AS-Ⅳ) on spatial learning and memory impairment induced by amyloid-beta 1-42 (Aβ1-42) in rats and elucidate its underlying molecular mechanisms. Methods Adult-male Sprague-Dawley rats (230-250 g) were divided into six groups randomly: control, Aβ1-42, AS-Ⅳ, Aβ1-42 plus 5 mg/kg·d AS-Ⅳ, Aβ1-42 plus 25 mg/kg·d AS-Ⅳ, and Aβ1-42 plus 50 mg/kg·d AS-Ⅳ groups. Aβ1-42 were delivered by intracerebroventricular injection under the guidance of a brain stereotaxic apparatus. The Morris water maze test (hidden platform test, probe trials, visible platform test) was performed one week after Aβ1-42 injection to obtain the ability of rat spatial learning and memory. AS-Ⅳ (5, 25 and 50 mg/kg·d) was administrated intraperitoneally once per day from the 8th day after Aβ1-42 injection for 5 consecutive days. Average escape latencies, distances for searching for the platform under water and the percentage of total time elapsed and distance swam in the right quadrant after removing platform were determined by behavior software system. The vision and swim speeds of rats were also determined to exclude the effect of these factors on the parameters of learning and memory. After behavioral tests, the rats were sacrificed immediately by decapitation. Hippocampus were collected. The enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT) in the hippocampus obtained from different-treated rat brain were measured by following the manufacturer's instructions. The levels of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in tissue lysates were assayed with ELISA. Results The water maze test results indicated that chronic treatments with AS-Ⅳ effectively protected the rats from Aβ1-42-induced spatial learning and memory impairment. Furthermore, the activities of SOD, GSH-px and CAT decreased by Aβ1-42 were also restored by AS-Ⅳ treatment in the hippocampus of rats. In addition, AS-Ⅳ significantly decreased the levels of IL-1β and TNF-α in the hippocampus of Aβ1-42-induced amnesia's rats. Conclusion Our findings suggest that AS-Ⅳ might be a useful chemical in improving the spatial memory and relieving the oxidative stress and neuroinflammation in Alzheimer patients.
ABSTRACT
Spinal cord injury is a serious trauma of the spinal and nervous system, local tissue destruction and microcirculation disturbance can lead to a more serious spinal cord injury and extensive necrosis of neurons. Spinal cord injury often accompany with Inflammation reaction producing a variety of cytokines and bioactive substances, result in macrophage polarization. M1 macrophages polarization are induced by IFN-γ, LPS, TNF-α and so on, it show the damage and proinflammatory effect. M2 macrophages polarization are caused by IL-4, IL-10, IL-13 and show the recovery and anti-inflammatory effect. However, clinical treatment after spinal cord injury is very limited, inhibition of proinflammatory and promotion of anti-inflammatory by regulating the M1 macrophages and M2 macrophages is a new direction for the treatment of spinal cord injury. The article will review different phenotype and function of macrophages after spinal cord injury.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the effects of brain-derived neurotrophic factor (BDNF) pretreatment on beta amyloid protein (Abeta) induced impairment of in vivo hippocampal long-term potentiation (LTP) in the CA1 region of rats.</p><p><b>METHODS</b>Thirty-six adult male SD rats were randomly divided into six groups (n = 6): control, Abeta25-35, BDNF, (0.02 microg, 0.1 microg, 0.5 microg) BDNF + Abeta25-35. A self-made hippocampal local drug delivery catheter and a parallel bound stimulating/recording electrode were used to deliver drugs/stimulation and record field excitatory post-synaptic potentials (fEPSPs) in the hippocampal CA1 region of rats. High-frequency stimulation (HFS) was used to induce in vivo LTP.</p><p><b>RESULTS</b>(1) Abeta25-35 (2 nmol) injection into CA1 region of rats did not affect the baseline fEPSPs, but inhibited the HFS-induced LTP significantly (P < 0.01). (2) Hippocampal CA1 injection of BDNF (0.1 microg) alone did not affect the baseline fEPSPs and HFS-induced LTP. (3) Compared with Abeta25-35 alone group, the averaged amplitude of LTP in BDNF (0.1 microg and 0.5 microg) plus Abeta25-35 groups significantly increased at 0 min, 30 min, and 60 min after HFS (P < 0.01), indicating that pretreatment with BDNF effectively protected against the Abeta,25-35 induced depression of LTP in a dose-dependent manner.</p><p><b>CONCLUSION</b>Intrahippocampal injection of BDNF can protect against the Abeta25-35-induced LTP impairment, suggesting that the up-regulation of BDNF in the brain could maintain the normal hippocampal synaptic plasticity and may contribute to the improvement of learning and memory in Alzheimer's (AD) disease patients.</p>