High-fat diet consumption promotes adolescent neurobehavioral abnormalities and hippocampal structural alterations via microglial overactivation accompanied by an elevated serum free fatty acid concentration.

Mounting evidence suggests that high-fat diet (HFD) consumption increases the risk for depression, but the neurophysiological mechanisms involved remain to be elucidated. Here, we demonstrated that HFD feeding of C57BL/6J mice during the adolescent period (from 4 to 8 weeks of age) resulted in increased depression- and anxiety-like behaviors concurrent with changes in neuronal and myelin structure in the hippocampus. Additionally, we showed that hippocampal microglia in HFD-fed mice assumed a hyperactive state concomitant with increased PSD95-positive and myelin basic protein (MBP)-positive inclusions, implicating microglia in hippocampal structural alterations induced by HFD consumption. Along with increased levels of serum free fatty acids (FFAs), abnormal deposition of lipid droplets and increased levels of HIF-1α protein (a transcription factor that has been reported to facilitate cellular lipid accumulation) within hippocampal microglia were observed in HFD-fed mice. The use of minocycline, a pharmacological suppressor of microglial overactivation, effectively attenuated neurobehavioral abnormalities and hippocampal structural alterations but barely altered lipid droplet accumulation in the hippocampal microglia of HFD-fed mice. Coadministration of triacsin C abolished the increases in lipid droplet formation, phagocytic activity, and ROS levels in primary microglia treated with serum from HFD-fed mice. In conclusion, our studies demonstrate that the adverse influence of early-life HFD consumption on behavior and hippocampal structure is attributed at least in part to microglial overactivation that is accompanied by an elevated serum FFA concentration and microglial aberrations represent a potential preventive and therapeutic target for HFD-related emotional disorders.

Voluntary wheel exercise ameliorates cognitive impairment, hippocampal neurodegeneration and microglial abnormalities preceded by demyelination in a male mouse model of noise-induced hearing loss.

Acquired peripheral hearing loss (APHL) in midlife has been identified as the greatest modifiable risk factor for dementia; however, the pathophysiological neural mechanisms linking APHL with an increased risk of dementia remain to be elucidated. Here, in an adult male mouse model of noise-induced hearing loss (NIHL), one of the most common forms of APHL, we demonstrated accelerated age-related cognitive decline and hippocampal neurodegeneration during a 6-month follow-up period, accompanied by progressive hippocampal microglial aberrations preceded by immediate-onset transient elevation in serum glucocorticoids and delayed-onset sustained myelin disruption in the hippocampus. Pretreatment with the glucocorticoid receptor antagonist RU486 before stressful noise exposure partially mitigated the early activation of hippocampal microglia, which were present at 7 days post noise exposure (7DPN), but had no impact on later microglial aberrations, hippocampal neurodegeneration, or cognitive decline exhibited at 1 month post noise exposure (1MPN). One month of voluntary wheel exercise following noise exposure barely affected either the hearing threshold shift or hippocampal myelin changes but effectively countered cognitive impairment and the decline in hippocampal neurogenesis in NIHL mice at 1MPN, paralleled by the normalization of microglial morphology, which coincided with a reduction in microglial myelin inclusions and a restoration of microglial hypoxia-inducible factor-1α (HIF1α) expression. Our results indicated that accelerated cognitive deterioration and hippocampal neuroplastic decline following NIHL are most likely driven by the maladaptive response of hippocampal microglia to myelin damage secondary to hearing loss, and we also demonstrated the potential of voluntary physical exercise as a promising and cost-effective strategy to alleviate the detrimental impact of APHL on cognitive function and thus curtail the high and continuously increasing global burden of dementia. Furthermore, the findings of the present study highlight the contribution of myelin debris overload to microglial malfunction and identify the microglial HIF1α-related pathway as an attractive candidate for future comprehensive investigation to obtain a more definitive picture of the underlying mechanisms linking APHL and dementia.

Clinical study on the treatment of knee osteoarthritis of Shen-Sui insufficiency syndrome type by electroacupuncture.

OBJECTIVE: To study the clinical effificacy of electroacupuncture (EA) on treating knee osteoarthritis (KOA) of Shen ()-Sui () insuffificiency (SSI) syndrome type. METHODS: A total of 245 patients (279 knees) of KOA-SSI were randomly assigned to two groups by lottery: 141 knees in the treatment group and 138 knees in the control group. The treatment group was managed with EA at the dominant points of Neixiyan (Ex-LE4) and Waixiyan (Ex-LE5) as well as the conjugate points of Xuanzhong (GB39) and Taixi (KI3) for 30 min, once a day, with 15 days as one course; 2 courses were applied with a 5-day interval in between. The control group was treated with intra-articular injection of 2 mL hyaluronic acid into the affected joint every 7 days for 5 times in total. The clinical effects on the patients in different stages were observed, and their symptom scores of knee and contents of cytokines, including interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), prostaglandin E(2alpha) (PGE(2alpha)) and matrix metalloproteinases-3 (MMP-3), in the knee joint fluid were measured before and after treatment. RESULTS: The study was completed in 235 patients (263 knees); four patients (7 knees) in the treatment group and six patients (9 knees) in the control group dropped out. Comparison of therapeutic effects (excellent and effective rates) between the two groups showed insignificant differences (P>0.05). Symptom scores of knee and contents of cytokines in the knee flfluid after treatment were lowered signifificantly in the patients of stage I-III in both groups (P<0.05 or P<0.01). However, the lowering of the total symptom score of knee in the patients of stage III in the treatment group was more signifificant (P<0.05). CONCLUSIONS: EA could effectively alleviate the clinical symptoms in KOA patients of stage III, showing an effect superior to that of hyaluronic acid. EA also shows action in suppressing the secretion of IL-1, IL-6, TNF-alpha, PGE(2alpha) and MMP-3 in the knee flfluid.