Effect of Electroacupuncture at GV20 on Sleep Deprivation-Induced Depression-Like Behavior in Mice

Abstract

Accumulating evidence suggests that sleep deprivation (S-Dep) is a critical risk factor for depression. Electroacupuncture (EA) treatment has been reported to ameliorate posttraumatic stress disorder- (PSTD-) like behavior and enhance hippocampal neurogenesis. However, whether EA treatment has any beneficial effect on S-Dep-induced depression-like behavior is still unknown. In the present study, we focused on whether EA at Baihui (GV20) can ameliorate the deterioration effect of S-Dep in mice. Mice were randomly divided into normal, S-Dep, S-Dep + EA, and S-Dep + sham EA groups. Cognitive behavior test and in vitro assay were performed separately to avoid the influence of behavior test on synaptic transmission and protein expression. Depression-like behaviors were determined by forced swimming test (FST), tail suspension test (TST), and Morris water maze (MWM). Neurogenesis was identified by BrdU, DCX, and NeuN immunofluorescence staining. In vitro long-term potentiation was detected by high frequency stimulation (HFS) at Schaffer collateral-CA1 synapses in hippocampal slices. Brain-derived neurotropic factor (BDNF) and tropomyosin receptor kinase B (TrkB) protein expression level were assayed by western blot. Our results indicated that D-Sep mice demonstrated depression-like behaviors determined by prolonged immobility duration in FST and TST; D-Sep mice also manifested spatial memory retention deficit in MWM. Furthermore, EA treatment ameliorated D-Sep-induced depression-like behaviors and spatial memory retention deficit. Mechanically, EA treatment alleviated neuron progenitor cell proliferation and differentiation, ameliorated the field excitatory postsynaptic potentials (fEPSPs) slope impaired by S-Dep, and elevated BDNF/TrkB protein expression. Taken together, our data suggested that EA treatment has a protective effect on S-Dep-induced depression-like behavior and cognitive impairment, which may be through regulating BDNF/TrkB protein expression.

Figure 1

Schematic illustration of the experimental procedure. All mice were assigned into four groups: normal, S-Dep, S-Dep + EA, and S-Dep + sham EA group. A set of mice containing 10 mice were exposed to MWM training phase test during 5 consecutive days, followed by 48 h of S-Dep and EA or sham EA treatment once daily; on the 7th day after the last EA treatment, mice were used for exploring phase test. Another set of mice containing 10 mice underwent TST and FST; 3 h recovery time was given after TST. Two separated sets of mice from each group were sacrificed after S-Dep and EA/sham EA treatment for LTP/western blot or immunofluorescence.

Figure 2

EA reversed depression-like behavior induced by S-Dep. The immobility time on FST (a) and TST (b). Data were presented as the mean ± SD, n = 10; ^∗∗∗p < 0.001 vs. normal group; ^##p < 0.01 vs. sleep deprivation group.

Figure 3

EA mitigated spatial memory retention deficits induced by S-Dep. The spatial memory retention of mice was determined by MWM. (a) Representative traces of activity of mice in the MWM. Number of times of platform crossing (b) and percentage of time spent in target quadrant (c) during the exploring phase. Data were presented as the mean ± SD, n = 10; ^∗∗p < 0.001, ^∗∗∗p < 0.001 vs. normal group; ^##p < 0.01, ^###p < 0.001 vs. sleep deprivation group.

Figure 4

EA alleviated neuron progenitor cell differentiation in the DG of hippocampus. (a) Representative microphotograph of BrdU (red) and NeuN (green) double immunostaining showing matured newborn neurons in the DG. (b) Quantification of BrdU and NeuN double positive cells (yellow). Data were presented as the mean ± SD, n = 6; ^∗∗∗p < 0.01 vs. normal group; ^##p < 0.01 vs. sleep deprivation group.

Figure 5

EA alleviated neuron progenitor cell proliferation in the DG of hippocampus. (a) Representative microphotograph of BrdU (red) and DCX (green) double immunostaining showing immature neurons in the DG. (b) Quantification of BrdU and DCX double positive cells (yellow). Data were presented as the mean ± SD, n = 6; ^∗∗p < 0.01 vs. normal group; ^##p < 0.01 vs. sleep deprivation group.

Figure 6

EA abolished LTP impairment induced by S-Dep. (a) Representative traces of the fEPSPs in the CA1 region of hippocampus before and after HFS in the Schaffer collaterals. (b) Plot of fEPSPs slope values as a percentage of baseline. (c) fEPSPs slope values were averaged from the duration 50–60 min after HFS. Data were presented as the mean ± SD, n = 8; ^∗∗p < 0.01 vs. normal group; ^##p < 0.01 vs. sleep deprivation group.

Figure 7

EA reversed BDNF/TrkB expression in S-Dep mice. Expression of BDNF and TrkB in hippocampal CA1 region was detected by western blot. (a) Western blot bands of BDNF and TrkB; GAPDH was used as an internal control. (b) Quantified protein expression level of BDNF and TrkB. Data were presented as the mean ± SD, n = 8; ^∗∗∗p < 0.001 vs. normal group; ^###p < 0.001 vs. sleep deprivation.