RESUMO
Objective:To investigate the effect of ginkgo biloba extract (GBE) on oxidative stress in medial prefrontal cortex and excitatory/inhibitory balance of pyramidal neurons in chronic unpredictable mild stress (CUMS)-induced depressive model mice.Methods:Totally 48 SPF grade 7-week-old male C57BL/6J mice were divided into 4 groups according to random number table method: control+ saline group (CTRL+ Veh), control+ GBE group (CTRL+ GBE), model+ saline group (CUMS+ Veh), model+ GBE group (CUMS+ GBE), with 12 mice in each group.Mice in CUMS+ Veh group and CUMS+ GBE group were established by CUMS method, and mice in CTRL+ GBE group and CUMS+ GBE group were intraperitoneally injected with GBE (70 mg/kg) once a day, and mice in CTRL+ Veh group and CUMS+ Veh group were injected intraperitoneally with 0.9% sodium chloride solution.Then, the sucrose preference test, forced swimming test (FST) and tail suspension test (TST) were performed to evaluate the depressive-like behavior of mice, and open field test (OFT) was performed to evaluate the autonomous locomotion and exploration ability and anxiety-like behavior.The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in mPFC were determined by ELISA.Spontaneous excitatory postsynaptic currents (sEPSC) and spontaneous inhibitory postsynaptic currents (sIPSC) were detected by whole-cell recording.SPSS 23.0 was used for data analysis and two-factor analysis of variance(whether to get GBE, whether to mold, show as GBE×CUMS) was used for statistical analysis.Results:(1) Behavioral results: the the time spent in center and total distance of OFT and sugar preference rate of the four groups of mice were compared, and the interaction of GBE×CUMS was significant( F=24.90, 4.82, 3.91, all P<0.05). The results of simple effect analysis showed that the time spent in center ((47.15±3.58) s), the total distance((19.33±0.86) m) and the sugar preference rate((59.11±8.79)%) of the mice in CUMS+ Veh group were lower than those in the CTRL+ Veh group((61.55±2.49) s, (23.24±1.21) m, (84.02±7.45) %) (all P<0.01), and the above indexes in CUMS+ GBE group ((56.51±3.53) s, (20.75±1.31) m, (70.80±11.79)%) were higher than those in CUMS+ Veh group (all P<0.05). In the immobility time of FST and TST of mice in the 4 groups, the interaction of GBE×CUMS were significant( F=85.53, 83.39, both P<0.01). The immobility time of FST and TST in CUMS+ Veh group were higher than those in CTRL+ Veh group (both P<0.01 ), and the above indexes in CUMS+ GBE group were lower than CUMS+ Veh group(both P<0.05). (2)The results of ELISA showed that the interaction of GBE×CUMS of SOD level of mice in the 4 groups was not significant ( F=3.52, P=0.07), but the main effects of GBE factor and CUMS factor were both significant ( F=4.69, 46.93, both P<0.05). The interaction of GBE×CUMS of MDA level was significant( F=16.61, P<0.01). The level of SOD in the CUMS+ Veh group was lower than that in the CTRL+ Veh group ( P<0.01), and the level of SOD in the CUMS+ GBE group was higher than that in the CUMS+ Veh group ( P<0.05). The level of MDA in the CUMS+ Veh group was higher than that of the CTRL+ Veh group ( P<0.01), and the level of MDA in CUMS+ GBE group was lower than that of the CUMS+ Veh group ( P<0.01). (3) The results of whole-cell recording showed that the interaction of GBE×CUMS of frequency and quantification of sEPSC in the four groups were significant ( F=5.45, 6.94, both P<0.05). The sEPSC frequency and quantification in the CUMS+ Veh group were lower than those in the CTRL+ Veh group (both P<0.01), and the sEPSC frequency and quantification in CUMS+ GBE group were higher than those of CUMS+ Veh group (both P<0.05). The interaction of GBE×CUMS of frequency and quantification of sIPSC in the four groups were significant ( F=7.78, 8.96, both P<0.01). The sIPSC frequency and quantification of the CUMS+ Veh group were higher than those of CTRL+ Veh group (both P<0.01), and the above indexes of CUMS+ GBE group were lower than those of CUMS+ Veh group (both P<0.01). As for the sEPSC/sIPSC ratio, GBE×CUMS interaction was significant ( F=5.45, P=0.02). The sEPSC/sIPSC ratio of CUMS+ Veh group (0.09±0.01) was lower than that of CTRL+ Veh group (0.28±0.04) ( P<0.01), and the sEPSC/sIPSC ratio of CUMS+ GBE group (0.14±0.03) was higher than that of CUMS+ Veh group ( P<0.05). Conclusion:Ginkgo biloba extract can improve the depression-like behavior of mice induced by CUMS, reduce the oxidative stress of mPFC and improve the excitation/inhibition balance of pyramidal neurons in depressive model mice.
RESUMO
Objective • To investigate the mechanism of spinal chemokine C-C motif receptor 2 (CCR2)-mediated maintenance of bone cancer pain (BCP) in rats. Methods • Fifty-four SD rats were divided into BCP group, sham operation group, BCP+INCB3344 (CCR2 specific antagonist) group, and BCP+vehicle control group. Walker256 breast cancer cells were injected into the tibia medullary cavity of rats in the BCP group to establish the BCP model, while the rats in the sham operation group were injected with the same amount of saline. The rats in the BCP+INCB3344 group received intrathecal injection of INCB3344 on the 14th day after the establishment of BCP model, while the BCP+vehicle control group rats were injected with the same amount of vehicle. The mechanical pain thresholds of BCP group rats and sham operation group rats were measured to judge the success of BCP model. The expressions of CCR2 in the dorsal horn of spinal cord in the sham operation group rats and the BCP group rats were detected by Western blotting. The effects of intrathecal administration of INCB3344 on the mechanical pain threshold of BCP rats were observed by mechanical pain behavior test. Whole-cell patch-clamp recordings were used to investigate the differences of spontaneous excitatory postsynaptic currents (sEPSCs), α-amino-3-hydroxy-5-methyl-4-isoxazole-propionicacid (AMPA) and N-methyl-D-aspartic acid (NMDA)-induced currents of spinal substantia gelatinosa (SG) neurons of rats in the BCP group, the BCP+INCB3344 group and the BCP+vehicle control group. Results • Compared with the sham operation group, the mechanical pain threshold of BCP group rats reduced significantly on the 14th day after operation (P=0.000), and the expression of CCR2 in ipsilateral spinal cord of BCP group rats increased significantly (P=0.009). After intrathecal injection of INCB3344 for 4 h, the mechanical pain threshold of BCP+INCB3344 group rats was significantly increased (P=0.002). The frequency and amplitude of sEPSCs and the amplitude of AMPA and NMDA-induced currents in SG neurons of BCP group rats were significantly higher than those of the sham operation group rats (all P=0.000), while intrathecal administration of INCB3344 could significantly inhibit the above-mentioned indices in the BCP+INCB3344 group (all P<0.05). In addition, extracellular perfusion of INCB3344 could also significantly inhibit the frequency (P=0.001) and amplitude (P=0.020) of sEPSCs in SG neurons in BCP rats. Conclusion • CCR2 expressing in the spinal cord mediates the enhancement of excitatory synaptic transmission efficacy in the spinal dorsal horn of BCP rats by enhancing the functions of AMPA and NMDA receptors, which may be an important mechanism for the maintenance of BCP.