The role of oxidative stress and inflammatory response in high-fat diet induced peripheral neuropathy

The effects of voluntary exercise on histological and stereological changes of sciatic nerve, nitric oxide levels, and peripheral neuropathy caused by high-fat diet-induced type 2 diabetes in male rats

This research was conducted to investigate the possible beneficial impacts of voluntary exercise on sciatic tissue, nitric oxide levels, stereological changes, and peripheral neuropathy caused by "high-fat-diet (HFD)"-induced "type 2 diabetes mellitus (T2DM)" in male rats. Rats were put into four experimental groups at random: "healthy control (C), voluntary exercise (VE), diabetic (D), and diabetic rats treated by voluntary exercise (VED)"; each group contain eight animals. Animals in VE and VED groups performed "voluntary exercise (VE)" for ten weeks. Animals in D and VED groups became diabetic after receiving a HFD for four weeks and an intraperitoneal injection (IP) of "streptozotocin (STZ)" (35 mg/kg). In order to evaluate mechanical and thermal algesia, hot plate, tail withdrawal, and von Frey tests were carried out. At the end of this study, serum NOx levels were assessed, and histological and stereological analyses were conducted. Mechanical nociceptive thresholds indicated considerable reduction (p < 0.001) which was followed by a remarkable enhance (p < 0.001) in thermal nociceptive threshold of D group. Tissue changes were also seen in sciatic nerve of D group. Voluntary exercise modified thermal and mechanical sensitivity in diabetic rats. It also improved the damaged sciatic nerve in diabetic animals.

Novel Insights into Total Flavonoids of Rhizoma Drynariae against Meat Quality Deterioration Caused by Dietary Aflatoxin B1 Exposure in Chickens

Aflatoxin B1 (AFB1) is a group of highly toxic mycotoxins that are commonly found in human and animal foods and threaten animal and human food safety. Total flavonoids of Rhizoma Drynaria (TFRD), a traditional Chinese medicinal herb, exert multiple biological activities such as immunomodulatory, anti-inflammatory, and anti-oxidation effects. Here, a total of 160 healthy 21-day-old male broilers were randomly divided into four groups: the CON group, the TFRD group, the AFB1 group, and the AFB1 + TFRD group. The study found that AFB1 exposure altered the breast meat quality-related indicators, including meat sensory and physical indicators. Metabolomics analysis further showed that the change in meat quality was closely associated with significantly differential metabolites of breast muscle. Furthermore, spotlighted amino acid content contributes to changes in the secondary structure of the myofibrillar protein by Raman spectroscopy analysis, which was associated with the oxidative stress and inflammatory response in AFB1-exposed breast meat. Meanwhile, dietary 125 mg/kg TFRD supplementation could effectively restore the changes in breast meat quality. Taken together, these results by multi-technical analysis revealed that AFB1 exposure causes deterioration of chicken meat quality and that TFRD may be a potential herbal extract to antagonize mycotoxicity.

Neuronal Inflammation is Associated with Changes in Epidermal Innervation in High Fat Fed Mice

Peripheral neuropathy (PN), a debilitating complication of diabetes, is associated with obesity and the metabolic syndrome in nondiabetic individuals. Evidence indicates that a high fat diet can induce signs of diabetic peripheral PN in mice but the pathogenesis of high fat diet-induced PN remains unknown. PURPOSE: Determine if neuronal inflammation is associated with the development of mechanical hypersensitivity and nerve fiber changes in high fat fed mice. METHODS: Male C57Bl/6 mice were randomized to a standard (Std, 15% kcal from fat) or high fat diet (HF, 54% kcal from fat) for 2, 4, or 8 weeks (n = 11-12 per group). Lumbar dorsal root ganglia were harvested and inflammatory mediators (IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-17, MCP-1, IFN-γ, TNF-α, MIP-1α, GMCSF, RANTES) were quantified. Hindpaw mechanical sensitivity was assessed using the von Frey test. Intraepidermal nerve fiber density (IENFD) and TrkA nerve fiber density were quantified via immunohistochemistry. RESULTS: After 8 weeks, HF had greater body mass (33.3 ± 1.0 vs 26.7 ± 0.5 g, p < 0.001), fasting blood glucose (160.3 ± 9.4 vs 138.5 ± 3.4 mg/dl, p < 0.05) and insulin (3.58 ± 0.46 vs 0.82 ± 0.14 ng/ml, p < 0.001) compared to Std. IL-1α, RANTES and IL-5 were higher in HF compared to Std after 2 and 4 weeks, respectively (IL-1α: 4.8 ± 1.3 vs 2.9 ± 0.6 pg/mg, p < 0.05; RANTES: 19.6 ± 2.2 vs 13.3 ± 1.2 pg/mg p < 0.05; IL-5: 5.8 ± 0.7 vs 3.1 ± 0.5 pg/mg, p < 0.05). IENFD and TrkA fiber density were also higher in HF vs Std after 4 weeks (IENFD: 39.4 ± 1.2 vs 32.2 ± 1.3 fibers/mm, p < 0.001; TrkA: 30.4 ± 1.8 vs 22.4 ± 1.3 fibers/mm). There were no significant differences in hindpaw sensitivity for Std vs HF. CONCLUSION: Increased inflammatory mediators preceded and accompanied an increase in cutaneous pain sensing nerve fibers in high fat fed mice but was not accompanied by significant mechanical allodynia. Diets high in fat may increase neuronal inflammation and lead to increased nociceptive nerve fiber density.

Protective effects of Aster yomena (Kitam.) Honda from cognitive dysfunction induced by high-fat diet

In our study, we investigated whether Aster yomena (Kitam.) Honda (AY) improved cognitive impairment which results from consumption of high-fat diet (HFD). When ethyl acetate fraction from AY (EFAY) was administered to C57BL/6J mice fed with 60% HFD, EFAY significantly enhanced cognitive ability that was impaired by HFD in T-maze test and novel object recognition test. Furthermore, EFAY increased memory and learning functions that were proven during Morris water maze test. We further elucidated protective mechanisms of EFAY against cognitive decline that resulted from obesity by western blotting. In the brain, HFD increased neuronal inflammation and disturbed insulin receptor substrate-1 (IRS-1)/Akt pathway. However, EFAY significantly downregulated inflammation-related protein expressions such as nuclear factor-κB interleukin-1β, inducible nitric oxide synthase and cyclooxygenase-2, compared with the HFD-fed control group. Furthermore, the IRS-1/Akt pathway was regulated by EFAY, indicating that EFAY ameliorated insulin resistance in the brain. PRACTICAL APPLICATIONS: Obesity and its complications increase the risk for developing cognitive dysfunction such as dementia. Administration of ethyl acetate fraction from AY (EFAY)-attenuated cognitive and memory impairment by inhibitions of neuronal oxidative stress and low-grade chronic inflammation in high-fat diet (HFD)-induced cognitive impairment mouse model. In addition, EFAY-administered mice disturbed cerebral insulin receptor substrate-1 (IRS-1)/Akt pathway. These data suggest that EFAY-improved cognitive impairment induced by HFD through modulation of insulin resistance and inflammation. Therefore, we proposed that AY could be a potential agent to prevent cognitive dysfunction induced by obesity and insulin resistance.

Unraveling the molecular mechanisms of hyperlipidemia using integrated lncRNA and mRNA microarray data

Long non-coding RNAs (lncRNAs) have key roles in various diseases; however, their functions in hyperlipidemia (HLP) have remained elusive. In the present study, microarray technology was utilized to analyze the differential expression of lncRNAs and mRNAs in liver tissues of apolipoprotein E^-/- mice as a model of HLP compared with control mice. A total of 104 and 96 differentially expressed lncRNAs and mRNAs, respectively, were identified. Differentially expressed genes were significantly enriched in biological processes such as nitric oxide biosynthesis, innate immune response and inflammatory response. Finally, two pairs of target genes and 38 transcription factors with regulatory functions in HLP were predicted based on the lncRNA and mRNA co-expression network. The lncRNA expression profile was significantly altered in liver tissues of the mouse model of HLP and may provide novel targets for research into treatments.

Designing a Logistic Regression Model for a Dataset to Predict Diabetic Foot Ulcer in Diabetic Patients: High-Density Lipoprotein (HDL) Cholesterol Was the Negative Predictor

OBJECTIVES

Although the risk factors for diabetic neuropathy and diabetic foot ulcer have been detected, there was no practical modeling for their prediction. We aimed to design a logistic regression model on an Iranian dataset to predict the probability of experiencing diabetic foot ulcers up to a considered age in diabetic patients.

METHODS

The present study was a statistical modeling on a previously published dataset. The covariates were sex, age, body mass index (BMI), fasting blood sugar (FBS), hemoglobin A1C (HbA1C), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), insulin dependency, and statin use. The final model of logistic regression was designed through a manual stepwise method. To study the performance of the model, an area under receiver operating characteristic (AUC) curve was reported. A scoring system was defined according to the beta coefficients to be used in logistic function for calculation of the probability.

RESULTS

The pretest probability for the outcome was 30.83%. The final model consisted of age (β1 = 0.133), BMI (β2 = 0.194), FBS (β3 = 0.011), HDL (β4 = -0.118), and insulin dependency (β5 = 0.986) (P < 0.1). The performance of the model was definitely acceptable (AUC = 0.914).

CONCLUSION

This model can be used clinically for consulting the patients. The only negative predictor of the risk is HDL cholesterol. Keeping the HDL level more than 50 (mg/dl) is strongly suggested. Logistic regression modeling is a simple and practical method to be used in the clinic.

The Potential Role of Fatty Acids in Treating Diabetic Neuropathy

PURPOSE OF REVIEW

This review will summarize recent findings of the effect of supplemental fatty acids, with an emphasis on omega-3 polyunsaturated fatty acids, as a treatment for diabetic peripheral neuropathy.

RECENT FINDINGS

Pre-clinical studies have provided evidence that treating diabetic rodents with δ linolenic acid (omega-6 18:3) and to a greater extent with eicosapentaenoic and docosahexaenoic acids (omega-3 20:5 and 22:6, respectively) improve and even reverse vascular and neural deficits. Additional studies have shown resolvins, metabolites of eicosapentaenoic and docosahexaenoic acids, can induce neurite outgrowth in neuron cultures and that treating type 1 or type 2 diabetic mice with resolvin D1 or E1 provides benefit for peripheral neuropathy similar to fish oil. Omega-3 polyunsaturated fatty acids derived from fish oil and their derivatives have anti-inflammatory properties and could provide benefit for diabetic peripheral neuropathy. However, clinical trials are needed to determine whether this statement is true.

Physical Training and Activity in People With Diabetic Peripheral Neuropathy: Paradigm Shift

Diabetic peripheral neuropathy (DPN) occurs in more than 50% of people with diabetes and is an important risk factor for skin breakdown, amputation, and reduced physical mobility (ie, walking and stair climbing). Although many beneficial effects of exercise for people with diabetes have been well established, few studies have examined whether exercise provides comparable benefits to people with DPN. Until recently, DPN was considered to be a contraindication for walking or any weight-bearing exercise because of concerns about injuring a person's insensitive feet. These guidelines were recently adjusted, however, after research demonstrated that weight-bearing activities do not increase the risk of foot ulcers in people who have DPN but do not have severe foot deformity. Emerging research has revealed positive adaptations in response to overload stress in these people, including evidence for peripheral neuroplasticity in animal models and early clinical trials. This perspective article reviews the evidence for peripheral neuroplasticity in animal models and early clinical trials, as well as adaptations of the integumentary system and the musculoskeletal system in response to overload stress. These positive adaptations are proposed to promote improved function in people with DPN and to foster the paradigm shift to including weight-bearing exercise for people with DPN. This perspective article also provides specific assessment and treatment recommendations for this important, high-risk group.

Effect of 2 different anesthesia methods on stress response in neurosurgical patients with hypertension or normal: A prospective clinical trial

Hypertensive patients in neurosurgery are becoming more common, which increased the risk of surgical stress response. Meanwhile, the relationship between hypertension and anesthesia methods is unclear on the stress response. The purpose of this study is to compare the effect of different anesthesia methods on high-sensitivity C-reactive protein (Hs-CRP), blood glucose, and leucocyte levels in neurosurgical patients with hypertension or normal.Eighty neurosurgical patients were randomly divided into 4 groups (n = 20): balanced anesthesia group (A), balanced anesthesia with hypertension group (B), total intravenous anesthesia group (C), total intravenous anesthesia with hypertension group (D). The levels of Hs-CRP, blood glucose, leucocyte count, and neutrophil percentage and were detected at before anesthesia (T0), during anesthesia (T1), 2 hours post anesthesia (T2), 24 hours post anesthesia (T3).Patients with hypertension had higher Hs-CRP expression, blood glucose, and neutrophil percentage at time T0 than those of normal, but not leucocyte count. At time T3, patients with hypertension in D group had lower Hs-CRP expression than those in B group (P < 0.01). Patients with normal in C group had lower Hs-CRP expression (P < 0.01), blood glucose (P < 0.05), and leukocyte count (P < 0.05) than those in A group. Both hypertension history and anesthesia method had significant effects on the Hs-CRP expression, blood glucose, and leukocyte count.Total intravenous anesthesia decreases Hs-CRP expressions more efficiently than balanced anesthesia in neurosurgical patients with hypertension or normal. Moreover, total intravenous anesthesia can availably reduce the perioperative stress response by attenuating the increase of blood glucose and leukocyte count in normal tensive patients.

An association analysis of lipid profile and diabetic cardiovascular autonomic neuropathy in a Chinese sample

Background

Recent studies have shown that triglyceride (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL) are related to the prevalence of cardiovascular autonomic neuropathy (CAN). However, little is known about the association of lipid profile with diabetic cardiovascular autonomic neuropathy (DCAN), or its severity in the Chinese population. The purpose of this study is to explore the extent of this phenomenon using a Chinese sample.

Methods

A subgroup analysis on 455 diabetic patients with undiagnosed DCAN was performed to evaluate the relationships of lipids profile and DCAN. DCAN was diagnosed if there were at least two abnormal cardiovascular autonomic reflex test results, based on short-term heart rate variability tests. Multivariable logistic regression (MLR)was carried out to control potential confounders for determining the independent association of variables with DCAN in different models.

Results

MLR analysis indicated that TG was significantly and independently associated with DCAN when controlling for confounding factors (P < 0.1 for two models). Additionally, TG combined with TC (LRS-1) and LDL (LRS-2) was associated with this outcome (P < 0.1 for LRS-1 and LRS-2).

Conclusion

Our findings indicate that TG and the severity of lipids profile is significantly and independently associated with DCAN, respectively.

Trial registration

ClinicalTrials.gov Identifier: NCT02461472, retrospectively registered 2 Jun, 2015

Effects of cepae extract, allantoin, and heparin mixture on developing andalready formed epidural fibrosis in a rat laminectomy model

BACKGROUND/AIM

The study was designed to investigate whether local administration of a mixture composed of cepae extract, allantoin, and heparin (CAH) decreased already formed epidural fibrosis (EF) at the laminectomy site.

MATERIALS AND METHODS

Twenty-four adult male Sprague Dawley rats were equally divided into four groups. Laminectomy was performed at the L5 level in all rats. The group 2 and group 4 rats were treated with local drug administration. While the group 1 and 2 rats were sacrificed after 6 weeks, the remaining rats were reoperated and CAH mixture was applied in group 4. The vertebral columns of all rats were removed en bloc. Fibroblast numbers, EF, and arachnoidal involvement (AI) were evaluated.

RESULTS

The results of the treatment groups were separately compared with the control groups. The numbers of fibroblasts in the treatment groups were significantly lower than those in the control groups (P < 0.001). The grade of EF in group 2 was significantly less than that in group 1 (P < 0.05). There was no statistically significant difference regarding EF and AI grade between group 3 and group 4, and local application of the drug on EF and AI yielded better results than in the control groups.

CONCLUSION

The mixture composed of CAH might be a successful candidate for preventing EF in clinical practice.

The effects of ankaferd blood stopper and microporous polysaccharide hemospheres on epidural fibrosis in rat laminectomy model

PURPOSE

To investigate whether topically administered hemostatic agents ankaferd blood stopper and microporous polysaccharide hemospheres can decrease epidural fibrosis after laminectomy in rats.

METHODS

Eighteen adult male Sprague-Dawley rats were equally and randomly divided into three groups. In the treatment groups, ankaferd blood stopper and microporous polysaccharide hemospheres topically administrated upon duramater surface after laminectomy. Fibroblast count, epidural fibrosis and arachnoidal involvement were evaluated and graded histopathologically.

RESULTS

Our data revealed that the count of fibroblasts, the grading of epidural fibrosis and arachnoideal involvement in the rats treated with microporous polysaccharide hemospheres were significantly less than the control group. Although the arachnoideal involvement in ankaferd blood stopper group were significantly less than the control group, there were no statistical differences when comparing the grading of epidural fibrosis and the fibroblasts count between the treatment groups and the control group.

CONCLUSION

The ankaferd blood stopper and microporous polysaccharide hemospheres reduced epidural fibrosis and arachnoideal involvement after laminectomy in rats.

Short-Term High Fat Intake Does Not Significantly Alter Markers of Renal Function or Inflammation in Young Male Sprague-Dawley Rats

Chronic high fat feeding is correlated with diabetes and kidney disease. However, the impact of short-term high fat diets (HFD) is not well-understood. Six weeks of HFD result in indices of metabolic syndrome (increased adiposity, hyperglycemia, hyperinsulinemia, hyperlipidemia, hyperleptinemia, and impaired endothelium-dependent vasodilation) compared to rats fed on standard chow. The hypothesis was that short-term HFD would induce early signs of renal disease. Young male Sprague-Dawley rats were fed either HFD (60% fat) or standard chow (5% fat) for six weeks. Morphology was determined by measuring changes in renal mass and microstructure. Kidney function was measured by analyzing urinary protein, creatinine, and hydrogen peroxide (H₂O₂) concentrations, as well as plasma cystatin C concentrations. Renal damage was measured through assessment of urinary oxDNA/RNA concentrations as well as renal lipid peroxidation, tumor necrosis factor alpha (TNFα), and interleukin 6 (IL-6). Despite HFD significantly increasing adiposity and renal mass, there was no evidence of early stage kidney disease as measured by changes in urinary and plasma biomarkers as well as histology. These findings suggest that moderate hyperglycemia and inflammation produced by short-term HFD are not sufficient to damage kidneys or that the ketogenic HFD may have protective effects within the kidneys.

Cutaneous expression of calcium/calmodulin-dependent protein kinase II in rats with type 1 and type 2 diabetes

Changes in calcium-calmodulin protein kinase II (CaMKII) have been well demonstrated in nervous tissue of diabetic animal models. Skin shares the same ectodermal origin as nervous tissue and it is often affected in diabetic patients. The goal of this study was to analyze expression of CaMKII in rat foot pad 2 weeks and 2 months after induction of diabetes type 1 and 2. Forty-two Sprague-Dawley rats were used. Diabetes mellitus type 1 (DM1) was induced with intraperitoneally (i.p.) injected 55 mg/kg of streptozotocin (STZ) and diabetes mellitus type 2 (DM2) with a combination of high-fat diet (HFD) and i.p. injection of low-dose STZ (35 mg/kg). Two weeks and two months following diabetes induction rats were sacrificed and skin samples from plantar surface of the both hind paws were removed. Immunohistochemistry was performed for detection of total CaMKII (tCaMKII) and its alpha isoform (pCaMKIIα). For detection of intraepidermal nerve fibers polyclonal antiserum against protein gene product 9.5 (PGP 9.5) was used. The results showed that CaMKII was expressed in the skin of both diabetic models. Total CaMKII was uniformly distributed throughout the epidermis and pCaMKIIα was limited to stratum granulosum. The tCaMKII and pCaMKIIα were not expressed in intraepidermal nerve fibers. Two weeks after induction of diabetes in rats there were no significant differences in expression of tCaMKII and pCaMKIIα between DM1 and DM2 compared to respective controls. In the 2-month experiments, significant increase in epidermal expression of tCaMKII and pCaMKIIα was observed in DM1 animals compared to controls, but not in DM2 animals. This study is the first description of cutaneous CaMKII expression pattern in a diabetic model. CaMKII could play a role in transformation of skin layers and contribute to cutaneous diabetic changes. Further research on physiological role of CaMKII in skin and its role in cutaneous diabetic complications should be undertaken in order to elucidate its function in epidermis.