Chronic ghrelin administration suppresses IKK/NF-κB/BACE1 mediated Aß production in primary neurons and improves cognitive function via upregulation of PP1 in STZ-diabetic rats.

Diabetic rats display cognition impairments accompanied by activation of NF-κB signalling and increased Aß expression. Ghrelin has been suggested to improve cognition in diabetic rats. In this study, we investigated the role of ghrelin on cognition and NF-κB mediated Aß production in diabetic rats. A diabetic rat model was established with streptozotocin (STZ) injection, and diabetic rats were intracerebroventricularly administered with ghrelin or (D-lys3)-GHRP-6 (DG). Our results showed that diabetic rats had cognition impairment in the Morris water maze test, accompanied by the higher expression of Aß in the hippocampus. Western blot analysis showed that diabetic rats exhibited significantly decreased levels of GHSR-1a and protein phosphatase 1 (PP1) in the hippocampus and increased activation of the IKK/NF-κB/BACE1 pathway. Chronic ghrelin administration upregulated hippocampal PP1 expression, suppressed IKK/NF-κB/BACE1 mediated Aß production, and improved cognition in STZ-induced diabetic rats. These effects were reversed by DG. Then, primary rat hippocampal neurons were isolated and treated with high glucose, followed by Ghrelin and DG, PP1 or IKK. Similar to the in vivo results, high glucose suppressed the expression levels of GHSR-1a and PP1, activated the IKK/NF-κB/BACE1 pathway, increased Aß production. Ghrelin suppressed IKK/NF-κB/BACE1 induced Aß production. This improvement was reversed by DG and a PP1 antagonist and was enhanced by the IKK antagonist. Our findings indicated that chronic ghrelin administration can suppress IKK/NF-κB/BACE1 mediated Aß production in primary neurons with high glucose treatment and improve the cognition via PP1 upregulation in diabetic rats.

Chronic Sleep Restriction Induces Aß Accumulation by Disrupting the Balance of Aß Production and Clearance in Rats.

Amyloid-ß (Aß) plays an important role in Alzheimer's disease (AD) pathogenesis, and growing evidence has shown that poor sleep quality is one of the risk factors for AD, but the mechanisms of sleep deprivation leading to AD have still not been fully demonstrated. In the present study, we used wild-type (WT) rats to determine the effects of chronic sleep restriction (CSR) on Aß accumulation. We found that CSR-21d rats had learning and memory functional decline in the Morris water maze (MWM) test. Meanwhile, Aß42 deposition in the hippocampus and the prefrontal cortex was high after a 21-day sleep restriction. Moreover, compared with the control rats, CSR rats had increased expression of ß-site APP-cleaving enzyme 1 (BACE1) and sAPPß and decreased sAPPα levels in both the hippocampus and the prefrontal cortex, and the BACE1 level was positively correlated with the Aß42 level. Additionally, in CSR-21d rats, low-density lipoprotein receptor-related protein 1 (LRP-1) levels were low, while receptor of advanced glycation end products (RAGE) levels were high in the hippocampus and the prefrontal cortex, and these transporters were significantly correlated with Aß42 levels. In addition, CSR-21d rats had decreased plasma Aß42 levels and soluble LRP1 (sLRP1) levels compared with the control rats. Altogether, this study demonstrated that 21 days of CSR could lead to brain Aß accumulation in WT rats. The underlying mechanisms may be related to increased Aß production via upregulation of the BACE1 pathway and disrupted Aß clearance affecting brain and peripheral Aß transport.

Depression as a risk factor for dementia and mild cognitive impairment: a meta-analysis of longitudinal studies.

BACKGROUND: This study examined whether depression was a risk factor for onset of dementia including Alzheimer's disease (AD), vascular dementia (VD) and any dementia, and mild cognitive impairment (MCI) by using a quantitative meta-analysis of longitudinal studies. METHODS: EMBASE and MEDLINE were searched for articles published up to February 2011. All studies that examined the relationship between depression and the onset of dementia or MCI were included. Pooled relative risk was calculated using fixed-effects models. RESULTS: Twelve studies met our inclusion criteria for this meta-analysis. All subjects were without dementia or MCI at baseline. Four, two, five, and four studies compared the incidence of AD, VD, any dementia, and MCI between subjects with or without depression, respectively. After pooling all the studies, subjects with depression had higher incidence of AD (relative risk (RR):1.66, 95% confidence interval (CI): 1.29-2.14), VD (RR: 1.89, 95% CI: 1.19-3.01), any dementia (RR: 1.55, 95% CI: 1.31-2.83), and MCI (RR: 1.97, 95% CI: 1.53-2.54) than those without depression. CONCLUSIONS: The quantitative meta-analysis showed that depression was a major risk factor for incidence of dementia (including AD, VD, and any dementia) and MCI.

Diabetes influences the fusion of autophagosomes with lysosomes in SH-SY5Y cells and induces Aß deposition and cognitive dysfunction in STZ-induced diabetic rats.

Diabetes has been regarded as an independent risk factor for Alzheimer's disease (AD). Our previous study found that diabetes activated autophagy, but lysosome function was impaired. Autophagy-lysosome dysfunction may be involved in Aß deposition in diabetic cognitive impairment. In the present study, we used STZ-induced diabetic rats and SH-SY5Y cells to investigate whether diabetes inhibits autophagosome fusion with lysosomes. We found that in the in vivo study, STZ-induced diabetic rats exhibited cognitive dysfunction, and the lysosome function-related factors CTSL, CTSD, and Rab7 were decreased (P < 0.05). In an in vitro study, the mRFP-GFP-LC3 assay showed that the fusion of autophagosomes with lysosomes was partly blocked in SH-SY5Y cells. High glucose treatment downregulated the number of autophagolysosomes, downregulated CTSD, CTSL, and Rab7 expression (P < 0.05), and then influenced the function of ACP2 to partly block the fusion of autophagosomes and lysosomes to inhibit Aß clearance. These findings indicate that high glucose treatment affected lysosome function, interfered with the fusion of autophagosomes with lysosomes, and partly blocked autophagic flux to influence Aß clearance.

Coptisine mitigates diabetic nephropathy via repressing the NRLP3 inflammasome.

Diabetic nephropathy is a microvascular complication of diabetes mellitus, threatening the health of millions of people. Herein, we explored a blood glucose independent function of coptisine on diabetic nephropathy. A diabetic rat model was established by intraperitoneal administration of streptozotocin (65 mg/kg). Coptisine treatment (50 mg/kg/day) retarded body weight loss and reduced blood glucose. On the other hand, coptisine treatment also decreased kidney weight and the levels of urinary albumin, serum creatinine, and blood urea nitrogen, indicating an improvement of renal function. Treatment with coptisine also mitigated renal fibrosis, with alleviative collagen deposition. Likewise, in vitro study showed that coptisine treatment decreased apoptosis and fibrosis markers in HK-2 cells treated with high glucose. Furthermore, after coptisine treatment, the activation of NOD-like receptor pyrin domain containing protein 3 (NRLP3) inflammasome was repressed, with decreased levels of NLRP3, cleaved caspase-1, interleukin (IL)-1ß, and IL-18, indicating that the repression of NRLP3 inflammasome contributed to the effect of coptisine on diabetic nephropathy. In conclusion, this study revealed that coptisine mitigates diabetic nephropathy via repressing the NRLP3 inflammasome. It is indicated that coptisine may have the potential to be used in the diabetic nephropathy treatment.

Berberine protects against palmitate induced beta cell injury via promoting mitophagy.

BACKGROUND: Destruction of pancreatic beta cells is the most typical characteristic of diabetes. OBJECTIVE: We aimed to evaluate the effect of berberine (BBR), a bioactive isoquinoline derivative alkaloid, on beta cell injury. METHODS: Rodent pancreatic beta cell line INS-1 was treated with 0.5 mM palmitate (PA) for 24 h to establish an in vitro beta cell injury model. RESULTS: BBR at 5 µM promoted cell viability, inhibited cell apoptosis and enhanced insulin secretion in PA-induced INS-1 cells. BBR treatment also suppressed PA-induced oxidative stress in INS-1 cells, as evidenced by the decreased ROS production and increased activities of antioxidant enzymes. In addition, suppressed ATP production and reduced mitochondrial membrane potential were restored by BBR in PA-treated INS-1 cells. It was further determined that BBR affected the expressions of mitophagy-associated proteins, suggesting that BBR promoted mitophagy in PA-exposed INS-1 cells. Meanwhile, we found that BBR facilitated nuclear expression and DNA-binding activity of Nrf2, an antioxidative protein that can regulate mitophagy. Finally, a rescue experiment was performed and the results demonstrated that the effect of BBR on cell viability, apoptosis and mitochondrial function in PA-induced INS-1 cells were cancelled by PINK1 knockdown. CONCLUSIONS: BBR protects islet ß cells from PA-induced injury, and this protective effect may be achieved by regulating mitophagy. The present study may provide a novel therapeutic strategy for ß cell injury in diabetes mellitus.

The Relationship Between Pre-existing Coronary Heart Disease and Cognitive Impairment Is Partly Explained by Reduced Left Ventricular Ejection Fraction in the Subjects Without Clinical Heart Failure: A Cross-Sectional Study.

Background: Coronary heart disease (CHD) is closely associated with cognitive impairment, especially in severe cases of heart failure. However, it is unclear whether cardiac systolic function plays a role in the relationship between pre-existing CHD and cognitive impairment in subjects without clinical heart failure. Methods: In total, 208 subjects from the First Affiliated Hospital of Xi'an Jiaotong University were recruited from June 2014 to January 2015, and were divided into CHD (n = 118) and non-CHD (n = 90) groups according to the inclusion and exclusion criteria. The global cognitive function of all subjects was assessed by the Mini-Mental State Examination (MMSE) and cognitive impairment was defined as the score lower than the cutoff value. Left ventricular ejection fraction (LVEF) was measured using transthoracic echocardiograms. The relationship among pre-existing CHD, LVEF, and cognitive impairment was analyzed by multivariate logistic regression. Results: In total, 34 subjects met the criteria of cognitive impairment. Univariate analysis showed that the cognitive impairment prevalence in the CHD group was significantly higher than that in the non-CHD group (22.0 vs. 8.9%, p = 0.011). Multivariate logistic analysis revealed that CHD was significantly associated with a higher risk of cognitive impairment (odds ratio [OR] = 3.284 [95% CI, 1.032-10.450], p = 0.044) after adjusting for confounds except for LVEF. However, the OR of CHD decreased (OR = 2.127 [95% CI, 0.624-7.254], p = 0.228) when LVEF was further corrected as a continuous variable, and LVEF was negatively associated with the risk of cognitive impairment (OR = 0.928 [95% CI, 0.882-0.976], p = 0.004). Conclusion: Pre-existing CHD is associated with a higher risk of cognitive impairment, and such an association can be considerably explained by reduced LVEF. An impaired cardiac systolic function may play a key role in the relationship between CHD and cognitive impairment among patients with pre-heart failure conditions.

Ghrelin-attenuated cognitive dysfunction in streptozotocin-induced diabetic rats.

Diabetic encephalopathy is clinically characterized by acquired behavior and cognitive dysfunction but its pathogenesis is not clear. This study aimed to explore the pathogenesis of diabetic encephalopathy and the mechanisms of ghrelin to ameliorate cognitive dysfunction in diabetic rats. Thirty-six streptozotocin diabetic rat models were established; 12 weeks later, all the rats were randomly divided into 3 groups [diabetic model group (D), ghrelin treatment group (T1), and ghrelin and D-lys-3-GHRP-6 treatment group (T2)] of 12 each. Twelve normoglycemic rats were classified in the normal group (N). Learning and memory behaviors were measured using a spatial version of the Morris water maze test. The brain-derived neurotrophic factor (BDNF), cAMP responsive element binding protein (CREB), phosphorylated CREB (p-CREB), phosphorylated ERK1/2 (p-ERK1/2), caspase-3, and Bcl-xl protein expressions in the hippocampi of all the rats were detected using immunohistochemistry. The mRNA expressions of BDNF, CREB, and caspase-3 were examined using reverse transcription-polymerase chain reaction. The hippocampus neuronal apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling method. We found that learning and memory level in the ghrelin treatment group improved significantly, expression of Bcl-xl, BDNF, CREB, p-CREB, and p-ERK1/2 in the hippocampus was increased in the ghrelin treatment group, and the number of apoptotic neurons in the hippocampus decreased remarkably. Our results showed that the changes of BDNF, CREB, and hippocampus neuronal apoptosis might be involved in the pathogenesis of diabetic encephalopathy. We suggested that ghrelin improved cognitive ability in streptozotocin-induced diabetic rats by improving the expressions of BDNF and CREB and by attenuating hippocampus neuronal apoptosis. The effects of ghrelin depend on the receptor of ghrelin, GHSR-1a, and ERK1/2 pathway.

Common Variants in NUS1 and GP2 Genes Contributed to the Risk of Gestational Diabetes Mellitus.

Background: Recently, NUS1 and GP2 genes were reported to be associated with the risk of type 2 diabetes (T2D) in a Japanese population. Given the sharing of pathogenic contribution from genetic factors between T2D and gestational diabetes mellitus (GDM), we conducted the study to systematically examine the relationship of NUS1 and GP2 genes with the susceptibility to GDM in Chinese Han population. Methods: A total of 4,250 subjects comprised of 1,282 patients with GDM and 2,968 controls were recruited, and 20 tag single nucleotide polymorphisms (SNPs) (10 from NUS1 and 10 from GP2) were selected for genotyping. Association analyses were conducted for GDM and its related biomedical indexes including fasting glucose and HbA1c levels. Results: Two SNPs, rs80196932 from NUS1 (P=2.93×10-5) and rs117267808 from GP2 (P=5.68×10-5), were identified to be significantly associated with the risk of GDM. Additionally, SNP rs80196932 was significantly associated with HbA1c level in both patients with GDM (P=0.0009) and controls (P=0.0003), while SNP rs117267808 was significantly associated with fasting glucose level in both patients with GDM (P=0.0008) and controls (P=0.0007). Serum levels of protein NUS1 and GP2 were measured for the study subjects, and significant differences were identified among groups with different genotypes of SNP rs80196932 and rs117267808, respectively. Conclusions: Our findings indicate that NUS1 and GP2 genes contribute to the risk of GDM, which would help to offer the potential to improve our understanding of the etiology of GDM and, in turn, could facilitate the development of novel medicines and treatments for GDM.

Coptisine ameliorates renal injury in diabetic rats through the activation of Nrf2 signaling pathway.

The present study has been designed and carried out to evaluate the potential of coptisine on diabetic nephropathy. Diabetes was induced in SD rats through one single intraperitoneal injection of streptozotocin (65 mg/kg) method, and then diabetic rats were orally administered with 25 mg/kg/day coptisine or 50 mg/kg/day coptisine for 8 weeks. Severe impairment of renal function in rats with diabetes was observed as indicated by increased urine protein excretion, kidney hypertrophy index, serum creatinine level, and blood urea nitrogen level. Oxidative stress damage was observed as indicated by increased levels of reactive oxygen species, malondialdehyde, and decreased levels of glutathione, superoxide dismutase, and catalase. However, these alterations in kidneys of rats with diabetes were alleviated by administration of coptisine. Furthermore, the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2) and its targeted antioxidative genes heme oxygenase 1 and NADPH quinone oxidoreductase 1 in the diabetic kidneys were significantly increased after coptisine treatment. These results suggested that coptisine ameliorated oxidative renal injury in diabetic rats, and the possible mechanisms for the renoprotective effects of coptisine may be related to activation of the Nrf2 signaling pathway.

Berberine protects against diabetic retinopathy by inhibiting cell apoptosis via deactivation of the NF­κB signaling pathway.

A number of studies have reported that diabetic retinopathy (DR) is the major cause of blindness. Berberine (BBR) is a bioactive constituent that displays effects on blood glucose; however, the mechanism underlying the role of BBR during the development of DR is not completely understood. In the present study, a rat model of DR was successfully established. The eye tissues were removed and subsequently assessed by hematoxylin and eosin staining and the TUNEL assay. The catalase, malondialdehyde, reactive oxygen species, glutathione and superoxide dismutase contents of the eye tissues were measured. Müller cells were chosen for further in vitro experiments. Cell apoptosis was examined by Annexin V­FITC apoptosis detection and Hoechst staining, and the mitochondrial membrane potential was assessed by JC­1 mitochondrial membrane potential detection. BBR decreased ganglion cell layer, cell apoptosis, reduced diabetic­induced oxidative stress and deactivated the NF­κB signaling pathway in the rat model of DR. High glucose enhanced oxidative stress and induced mitochondria­dependent cell apoptosis in Müller cells by activating the NF­κB signaling pathway. BBR reversed the high glucose­induced effects by decreasing the phosphorylation of IκB, inhibiting NF­κB nuclear translocation and deactivating the NF­κB signaling pathway. The results suggested that BBR protected against DR by inhibiting oxidative stress and cell apoptosis via deactivation of the NF­κB signaling pathway; therefore, suggesting that BBR may serve as a promising therapeutic agent for DR.

Activation of Inflammation is Associated with Amyloid-ß Accumulation Induced by Chronic Sleep Restriction in Rats.

Alzheimer's disease (AD) is the most common age-associated neurodegenerative disease featured by progressive learning and memory deficit, and Aß was identified as playing a key role in the process of AD and was theorized to be caused by the imbalance of production and clearance. Increasing evidence suggested an association between sleep deprivation and AD. Our recent study found that chronic sleep restriction (CSR) caused cognitive impairment and Aß accumulation in rats, but the underlining mechanism was unclear. In the present study, we investigated the effects of inflammation on Aß accumulation induced by CSR. We found that CSR significantly increased the expression of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and nitric oxide (NO) in brain, and the inflammatory factors levels were positively correlated with Aß42 deposition. Additionally, the inflammatory factors were correlated with BACE1, LRP-1, and RAGE levels in both the hippocampus and the prefrontal cortex. Furthermore, the plasma levels of IL-1ß, TNF-α, and NO were elevated after CSR, and the concentration of plasma inflammatory mediators were correlated with plasma levels of sLRP1 and sRAGE. These results suggested that the inflammation in brain and plasma might be involved in the CSR-induced Aß accumulation.

Interactive relations of type 2 diabetes and abdominal obesity to cognitive impairment: A cross-sectional study in rural area of Xi'an in China.

AIMS: Type 2 diabetes and obesity, which are frequently comorbid, have been associated with cognitive impairment. We aim to examine the potential modulating effect between obesity and diabetes on cognitive impairment. METHODS: We recruited 865 adults (aged ≥55years) lived in a village of Xi'an in China from October 2014 to March 2015. All participants underwent biomedical and neuropsychological assessment. Relations of diabetes and abdominal obesity to cognitive impairment were examined in multiple regression models. RESULTS: A total of 155 participants (17.9%) presented with the diagnosis of cognitive impairment. Diabetes or obesity alone wasn't significantly associated with cognitive impairment. Interaction analysis showed a significant interaction between abdominal obesity and diabetes on cognitive impairment. Stratified multivariate analysis revealed that the association between diabetes and cognitive impairment was positive in participants with abdominal obesity (OR 2.436, 95% CI 1.345-4.411, p=0.003, in diabetics with high WC, and OR 2.348, 95% CI 1.373-4.014, p=0.002, in diabetics with high WHR), but negative in those without abdominal obesity. CONCLUSIONS: Type 2 diabetes interacts with abdominal obesity to be associated with an increased risk of cognitive impairment by more than two times.

Autophagy-lysosome dysfunction is involved in Aß deposition in STZ-induced diabetic rats.

ß-Amyloid (Aß) deposition has a central role in the pathogenesis of Alzheimer disease (AD). Previous studies have indicated that as a risk factor for AD, diabetes mellitus (DM) could induce Aß deposition in the brain, but the mechanism is not fully elucidated. Autophagy-lysosome is a cellular pathway involved in protein and organelle degradation. In the present study, we used streptozotocin (STZ)-induced diabetic rats to investigate whether autophagy-lysosome is related to Aß1-42 clearance in DM. We found that DM rats had a longer escape latency and less frequent entry into the target zone than that of the control group (p<0.05) in the Morris water maze test. Meanwhile, hippocampal neuron damage and apoptosis (p<0.05) were found in the DM rats. The Aß1-42 expression in the hippocampus significantly increased in the DM group compared with the control group (p<0.05). The markers of autophagy, beclin-1 and LC3 II, were increased (p<0.05), whereas LC3 I was decreased (p<0.05), and the ratio of LC3 II / I was increased as the time advanced (p<0.01). LAMP1 and LAMP2, which are the markers of lysosome function, were decreased in the hippocampus of DM rats (p<0.05). The Aß1-42 deposition was correlated with beclin-1, LC3 II, and LC3 I positively (p<0.05), but with LAMP1 and LAMP2 negatively (p<0.05). These findings indicate that DM activated autophagy, but lysosome function was impaired. Autophagy-lysosome dysfunction may be involved in the Aß deposition in diabetic cognitive impairment.

Sleep Deprivation Induced Plasma Amyloid-ß Transport Disturbance in Healthy Young Adults.

BACKGROUND: Sleep is an important physiological process and beneficial in the removal of brain metabolites and functional recovery. Prior studies have shown that sleep disorders are significant risk factors for Alzheimer's disease (AD). OBJECTIVE: The present study was designed to characterize the effect of short-term total sleep deprivation (TSD) on plasma amyloid-ß (Aß) concentrations. METHODS: A clinical trial was conducted between March 1, 2016, and April 1, 2016. Twenty volunteers (age 27.3±3.4 years) with normal cognitive function and sleeping habits were recruited from the local population. Participants underwent 24 h of TSD. Periprocedural blood samples were collected to compare the changes of plasma Aß42, Aß40, low-density lipoprotein receptor-related protein (sLRP-1), soluble receptors for advanced glycation end products (sRAGE), and serum superoxide dismutase (SOD) and malonaldehyde (MDA). RESULTS: TSD increased morning plasma Aß40 levels by 32.6% (p < 0.001) and decreased the Aß42/Aß40 ratio by 19.3% (p < 0.001). A positive relationship was found between TSD duration and plasma Aß40 level (r = 0.51, p < 0.001) and Aß40/Aß42 ratio (r = 0.25, p = 0.003). Plasma concentrations of sLRP1 (p = 0.018) and sRAGE (p = 0.001) decreased significantly after TSD. Aß40 and Aß42 plasma concentrations correlated with plasma levels of sLRP1 and sRAGE. Serum SOD decreased after TSD (p = 0.005), whereas serum MDA was increased (p = 0.001). CONCLUSION: Sleep deprivation can lead to an elevation of plasma Aß40 and decrease of the Aß42/Aß40 ratio. The underlying mechanisms may be related to increased oxidative stress and impaired peripheral Aß clearance as pathomechanisms of AD.

The Research on the Relationship of RAGE, LRP-1, and Aß Accumulation in the Hippocampus, Prefrontal Lobe, and Amygdala of STZ-Induced Diabetic Rats.

Diabetes mellitus (DM) has been regarded as an important risk factor for Alzheimer's disease (AD), and diabetic patients and animals have shown cognitive dysfunction. More research has shown that the amyloid-ß (Aß), which is a hallmark of AD, was found deposited in the hippocampus of diabetic rats. This Aß accumulation is regulated by the receptor for advanced glycation end products (RAGE) and low-density lipoprotein receptor-related protein (LRP-1). However, the expression of RAGE and LRP-1 in diabetic rats is not very clear. In the present study, we used streptozotocin (STZ)-induced diabetic rats to investigate whether the expression of RAGE and LRP-1 is related to Aß1-42 deposition at the hippocampus, prefrontal lobe, and amygdala in DM. We found that diabetic rats had longer escape latency and less frequency of entrance into the target zone than that of the control group (P < 0.05) in the Morris water maze (MWM) test. The Aß1-42 expression in the hippocampus and prefrontal lobe significantly increased in the DM group compared to the control group (P < 0.05). RAGE increased (P < 0.05), while LRP-1 decreased (P < 0.05) in the hippocampus tissue and prefrontal lobe tissue of DM rats. The Aß1-42 deposition was correlated with RAGE positively (P < 0.05), but with LRP-1 negatively (P < 0.05). Further, the expression levels of Aß1-42, RAGE, and LRP-1 were not changed in the amygdala between the diabetic rats and the control group. These findings indicated that upregulating RAGE and/or downregulating LRP-1 at the hippocampus and the prefrontal lobe contributed to the Aß1-42 accumulation and then further promoted the cognitive impairment of diabetic rats.

Electroacupuncture alleviates nerve injury after cerebra ischemia in rats through inhibiting cell apoptosis and changing the balance of MMP-9/TIMP-1 expression.

Accumulating evidence demonstrates that acupuncture and electroacupuncture (EA) can exert a neuroprotective role for cerebral ischemia, but their precise mechanism remains largely unknown. Therefore, in this study, the effects of EA stimulation on cerebral ischemia reperfusion and its neuroprotective mechanisms were investigated. A rat model of middle cerebral artery occlusion (MCAO) was developed, and EA stimulation (2Hz, 1mA) at Baihui and Siguan acupoints was applied 30min after MCAO and then once daily for 7 consecutive days. The results indicated that EA stimulation significantly reduced the cerebral infarct area and neurological deficit scores, decreased the number of apoptotic cells, up-regulated Bcl-2 protein expression, and down-regulated Bax protein expression. EA stimulation resulted in a significant increase of proliferative cells in the cerebral tissues. Additionally, EA stimulation significantly down-regulated the expression levels of matrix metalloproteinase -9 (MMP-9) mRNA and protein, and simultaneously up-regulated the expression levels of tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA and protein, which resulted in an imbalance of MMP-9/TIMP-1expression, although it did not significantly change MMP-2 and TIMP-2 expression. These findings indicate that EA stimulation at Baihui and Siguan acupoints exerts a neuroprotective role against cerebral ischemia-reperfusion injury, which is probably associated with the inhibition of apoptosis and altering the balance of MMP-9/TIMP-1 expression.