Chinese Tuina remodels the synaptic structure in neuropathic pain rats by downregulating the expression of N-methyl D-aspartate receptor subtype 2B and postsynaptic density protein-95 in the spinal cord dorsal horn.

OBJECTIVE: To investigate whether the Chinese massage system, Tuina, exerts analgesic effects in a rat model of chronic constriction injury (CCI) by remodeling the synaptic structure in the spinal cord dorsal horn (SCDH). METHODS: Sixty-nine male Sprague-Dawley rats were randomly and evenly divided into the normal group, sham group, CCI group, CCI + Tuina group, CCI + MK-801 [an -methyl D-aspartate receptor subtype 2B (NR2B) antagonist] group, and CCI + MK-801 + Tuina group. The neuropathic pain model was established using CCI with right sciatic nerve ligation. Tuina was administered 4 d after CCI surgery, using pressing manipulation for 10 min, once daily. Motor function was observed with the inclined plate test, and pain behaviors were observed by the Von Frey test and acetone spray test. At 19 d after surgery, the L3-L5 spinal cord segments were removed. Glutamate, interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) levels were detected by enzyme-linked immunosorbent assay. The protein expression levels of NR2B and postsynaptic density protein-95 (PSD-95) were detected by Western blot, and the synaptic structure was observed by transmission electron microscopy (TEM). RESULTS: CCI reduced motor function and caused mechanical and cold allodynia in rats, increased glutamate concentration and TNF-α and IL-1ß levels, and increased expression of synapse-related proteins NR2B and PSD-95 in the SCDH. TEM revealed that the synaptic structure of SCDH neurons was altered. Most of these disease-induced changes were reversed by Tuina and intrathecal injection of MK-801 ( < 0.05 or < 0.01). For the majority of experiments, no significant differences were found between the CCI + MK-801 and CCI + MK-801 + Tuina groups. CONCLUSIONS: Chinese Tuina can alleviate pain by remodeling the synaptic structure, and NR2B and PSD-95 receptors in the SCDH may be among its targets.

[Modified Kaixin San improves memory and synaptic damage of mice with Alzheimer's disease by modulating αCaMKâ ¡-PSD95 protein binding through inhibition of neuroinflammation:a study of mechanism].

To investigated the mechanisms underlying the effects of modified Kaixin San(MKXS) on improving memory and synaptic damage of Alzheimer's disease(AD) mouse model with conditional presenilin 1/2 conditional double knockout(PS cDKO). Specifically, 60 PS cDKO mice(3-3.5 months old) and their age-matched wild-type(WT) littermates were randomized into three groups: WT group(n=20), PS cDKO group(n=20), and PS cDKO+MKXS group(n=20). Mice in WT and PS cDKO groups were fed with standard chow and those in PS cDKO+MKXS group were given chow containing MKXS(at 2.55 g·kg~(-1)) for 60 days. Novel object reco-gnition task was employed to detect the recognition memory of mice, and Western blot to detect the protein levels of synapse-associated proteins in the hippocampus(HPC) of mice, such as NR1, NR2 A, NR2 B, p-αCaMKⅡ, tau, and p-tau. Microglial morphology in the HPC CA1 of mice was observed based on immunohistochemistry. Quantitative real time-PCR(qRT-PCR) was employed to detect the mRNA levels of the pro-inflammatory factors and synapse-associated proteins in the HPC of mice, including COX-2, iNOS, IL-1ß, IL-6, TNF-α, PSD95, NR1, NR2 A, NR2 B, and MAP2. The protein levels of IL-1ß, TNF-α, and IL-6 were tested by enzyme-linked immunosorbent assay(ELISA). The interaction between PSD95 and αCaMKⅡ and between PSD95 and p-αCaMKⅡ was tested by co-immunoprecipitation(Co-IP). The results showed that PS cDKO+MKXS demonstrated significantly higher preference index and recognition index of the new objects, lower protein level of p-tau(ser 396/404) and mRNA levels of COX-2, iNOS, TNF-α, IL-1ß, and IL-6 in HPC, higher protein levels of NR1, NR2 A, NR2 B, and p-αCaMKⅡ and mRNA levels of NR1, NR2 A, NR2 B, PSD95, and MAP2, and stronger interaction of αCaMKⅡ with PSD95 and interaction of p-αCaMKⅡ with PSD95 than the PS cDKO group. Immunohistoche-mical staining showed that MKXS inhibited the activation of microglia. In conclusion, MKXS improves memory and synaptic damage in mice with AD by modulating αCaMKⅡ-PSD95 protein binding through inhibition of neuroinflammation.

Hippocampal and Reticulo-Thalamic Parvalbumin Interneurons and Synaptic Re-Organization during Sleep Disorders in the Rat Models of Parkinson's Disease Neuropathology.

We investigated the alterations of hippocampal and reticulo-thalamic (RT) GABAergic parvalbumin (PV) interneurons and their synaptic re-organizations underlying the prodromal local sleep disorders in the distinct rat models of Parkinson's disease (PD). We demonstrated for the first time that REM sleep is a predisposing state for the high-voltage sleep spindles (HVS) induction in all experimental models of PD, particularly during hippocampal REM sleep in the hemiparkinsonian models. There were the opposite underlying alterations of the hippocampal and RT GABAergic PV+ interneurons along with the distinct MAP2 and PSD-95 expressions. Whereas the PD cholinopathy enhanced the number of PV+ interneurons and suppressed the MAP2/PSD-95 expression, the hemiparkinsonism with PD cholinopathy reduced the number of PV+ interneurons and enhanced the MAP2/PSD-95 expression in the hippocampus. Whereas the PD cholinopathy did not alter PV+ interneurons but partially enhanced MAP2 and suppressed PSD-95 expression remotely in the RT, the hemiparkinsonism with PD cholinopathy reduced the PV+ interneurons, enhanced MAP2, and did not change PSD-95 expression remotely in the RT. Our study demonstrates for the first time an important regulatory role of the hippocampal and RT GABAergic PV+ interneurons and the synaptic protein dynamic alterations in the distinct rat models of PD neuropathology.

Baicalin regulates depression behavior in mice exposed to chronic mild stress via the Rac/LIMK/cofilin pathway.

BACKGROUND: Depression is a common disease that endangers people's physical and mental health. Traditional Chinese medicine has advantages in treating the emotional and cognitive symptoms of depressive disorders. OBJECTIVE: To study the effects of baicalin on the behavior and to clarify the underlying mechanism through evaluation of the Rac1-LIMK1-cofilin pathway. METHODS: A chronic mild stress (CMS) model of depression was used. Baicalin was administered to the mice for the intervention, and the positive control group was treated with fluoxetine. Behavioral tests were conducted to observe the degree of depressive disorders. Synaptophysin (SYP), postsynaptic density protein-95 (PSD95), brain-derived neurotrophic factor (BDNF), tyrosine kinase receptors (TrkB), Rac1 and cofilin expression was determined using Western blot analysis, and mRNA was quantified using real-time PCR. RESULTS: Mice in the CMS group showed an increase in depression-like behavior (p < 0.01), while mice in the baicalin and fluoxetine groups showed a decrease in depression-like behavior (p < 0.01), compared with the control group. Electron microscopy showed ultrastructural changes in the hippocampal CA3 area of the CMS group, which were alleviated by baicalin treatment. SYP, PSD95, BDNF, TrkB, Rac1 and cofilin protein expression levels were decreased in the CMS group compared with the control group, while these levels were increased in the baicalin and fluoxetine groups (p < 0.01). There was no significant difference among the baicalin and fluoxetine groups (p > 0.05). CONCLUSION: Baicalin markedly alleviated depression-like behavioral changes, exerted effects on SYP, PSD95, BDNF, and TrkB expression, activated the Rac1-cofilin pathway, and subsequently improve synaptic plasticity.

The effects of omega-3 fatty acid deficiency during development on oxidative fatty acid degradation during maturity in a mouse model of Alzheimer's disease.

Metabolic conditions during brain development may have long-term consequences on brain metabolism, thereby influencing the risk of neurodegenerative disease in later life. To ascertain the long-term consequences of omega-3 (ω3) fatty acid deficiency during brain development on oxidative fatty acid degradation in the brain and the development of Alzheimer-like pathology, wild-type (WT) female mice were fed diets that were either replete or deficient in ω3 fatty acids for 5 weeks. These females were then mated with hemizygous 5xFAD male transgenic (TG) mouse models of Alzheimer's disease, and the progeny were continued on diets that were either ω3-replete or ω3-deficient. When the progeny were 6 months of age, they received radiolabeled arachidonic acid (ARA) by intracerebroventricular injection. Five days after these injections, the brains were harvested and oxidative degradation of the radiolabeled ARA was characterized. Among the progeny of female mice on an ω3-replete diet, TG progeny had lower PSD-95 expression and higher oxidative ARA degradation than WT progeny. Progeny on an ω3-deficient diet, however, had no significant differences in PSD-95 expression between TG and WT mice, or in the extent of ARA degradation. In TG mice, an ω3-deficient diet reduced oxidative ARA degradation to a greater extent than in WT mice. The reductions in oxidative ARA degradation occurred even if the progeny of female mice on an ω3-deficient diet resumed an ω3-replete diet immediately on weaning. These results demonstrate that dietary ω3 fatty acid deficiency during development can cause long-term changes in the expression of a synaptic marker and long-term reductions in the rate of ARA degradation in the WT brain, which are not completely alleviated by an ω3-replete diet after weaning. The elimination of differences between TG and WT mice by an ω3-deficient diet suggests that mechanisms regulating PSD-95 expression and the oxidative degradation of ARA are related and that the timing of dietary ω3 intake during development may influence Alzheimer's disease-related pathological changes later in life.