The effects of chromium histidinate on mineral status of serum and tissue in fat-fed and streptozotocin-treated type II diabetic rats

Understanding Cr(III) Action on Mitochondrial ATP Synthase and AMPK Efficacy: Insights from Previous Studies-a Review

Chromium supplementation has been notably recognized for its potential health benefits, especially in enhancing insulin sensitivity and managing glucose metabolism. However, recent studies have begun to shed light on additional mechanisms of action for chromium, expanding our understanding beyond its classical effects on the insulin-signaling pathway. The beta subunit of mitochondrial ATP synthase is considered a novel site for Cr(III) action, influencing physiological effects apart from insulin signaling. The physiological effects of chromium supplementation have been extensively studied, particularly in its role in anti-oxidative efficacy and glucose metabolism. However, recent advancements have prompted a re-evaluation of chromium's mechanisms of action beyond the insulin signaling pathway. The discovery of the beta subunit of mitochondrial ATP synthase as a potential target for chromium action is discussed, emphasizing its crucial role in cellular energy production and metabolic regulation. A meticulous analysis of relevant studies that were earlier carried out could shed light on the relationship between chromium supplementation and mitochondrial ATP synthase. This review categorizes studies based on their primary investigations, encompassing areas such as muscle protein synthesis, glucose and lipid metabolism, and antioxidant properties. Findings from these studies are scrutinized to distinguish patterns aligning with the new hypothesis. Central to this exploration is the presentation of studies highlighting the physiological effects of chromium that extend beyond the insulin signaling pathway. Evaluating the various independent mechanisms of action that chromium impacts cellular energy metabolism and overall metabolic balance has become more important. In conclusion, this review is a paradigm shift in understanding chromium supplementation, paving the way for future investigations that leverage the intricate interplay between chromium and mitochondrial ATP synthase.

Curcumin Mitigates Malathion-Induced Renal Injury: Suppression of Apoptosis and Modulation of NF-κβ/TNF-α and Nrf2, and HO-1 Signaling

Malathion is one of the most used organophosphorus pesticides that is used for many reasons such as agriculture and industry. Human exposure to malathion may occur through various means, such as eating food that has been treated with it. Malathion not only increases oxidative stress but also decreases the antioxidant capacity. Curcumin is a powerful antioxidant with many pharmacological actions. Curcumin can act as a free radical scavenger and inhibit the activation and nuclear translocation of NF-κB. Curcumin could combat the lipid peroxidation and antioxidant depletion that trigger the apoptotic pathways. This study aims to examine the antioxidant, anti-inflammatory, and antiapoptotic effects of curcumin. Twenty-four Sprague Dawley rats were divided into four groups (six rats each): control, curcumin, malathion, and malathion + curcumin groups. At the assigned time, blood samples were used for the assessment of serum creatinine, and the kidneys were excised and washed; parts of them were used for the assessment of total oxidant status (TOS), oxidative stress index (OSI), the oxidative stress marker malondialdehyde (MDA), total antioxidant capacity (TAC), and glutathione (GSH) activity, other parts were fixed in formalin for further staining. Histopathological evaluation was performed for the fixed specimens after staining with H&E, sirus red, and the immunohistochemical staining for NF-κβ, TNF-α, Caspase-3, Nrf2, and HO-1. Curcumin significantly decreases the serum creatinine after malathion exposure and significantly restores the oxidant/antioxidant balance by increasing TAC and GSH and decreasing TOS, OSI, and MDA. Curcumin exerts its reno-protective effect and restores the histological architecture of the kidney by downregulating the immune expression of NF-κβ, TNF-α, and Caspase-3 and upregulating the expression of Nrf2 and HO-1. This study concluded that curcumin protects against nephrotoxicity caused by malathion by exerting its antioxidant, anti-inflammatory, and anti-apoptotic capabilities.

Chemical Constituents, Bioactivities, and Pharmacological Mechanisms of Dendrobium officinale: A Review of the Past Decade

Dendrobium officinale, a plant in the Orchidaceae family, has been used in traditional Chinese medicine for thousands of years. Sweet and slightly cold in nature, it can invigorate the stomach, promote fluid production, nourish Yin, and dissipate heat. Over the past decade, more than 60 compounds have been derived from D. officinale, including flavonoids, bibenzyl, and phenanthrene. Various studies have explored the underlying pharmacological mechanisms of these compounds, which have shown antitumor, hypoglycemic, hypertensive, gastrointestinal-regulatory, visceral organ protection, antiaging, and neurorestorative effects. This paper presents a systematic review of the structural classification, biological activity, and pharmacological mechanisms of different chemical components obtained from D. officinale over the past decade. This review aims to provide a reference for future study and establish a foundation for clinical applications. Furthermore, this review identifies potential shortcomings in current research as well as potential directions and methodologies in future plant research.

ZIP14 is involved in iron deposition and triggers ferroptosis in diabetic nephropathy

Ferroptosis is caused by lipid peroxidation and iron accumulation and can cause cell death. Abnormally expressed iron transporters are involved in ferroptosis in a variety of diseases. ZRT/IRT-like protein 14 (ZIP14) is a transport protein that can mediate cellular uptake of iron, zinc and manganese. Herein, we have tested the hypothesis that the divalent metal transporter ZIP14 is involved in the initiation of ferroptosis in diabetic nephropathy (DN). DN was induced in eight-week old male rats by streptozotocin (STZ) before analysis of the degree of renal tubular injury. In addition, an in vitro model of DN in HK2 cells was used. We showed that ZIP14 was upregulated and Fe2+ levels increased both in vivo and in vitro. Expression of glutathione peroxidase 4 (GPX4) and the level of glutathione (GSH) were reduced, whereas that of malondialdehyde (MDA) increased. Ferrostatin-1(Fer-1) treatment reduced the expression of ZIP14 and the levels of Fe2+ and MDA, which is consistent with ferroptosis. Fer-1 improved kidney function in DN rats. This was characterized by urine levels of protein-to-creatinine ratio, α 1-microglobulin and N-acetyl-β-D-glucosaminidase. Our study demonstrates a novel role for ZIP14 in diabetic kidney injury mediated by ferroptosis, and suggests a potential new therapeutic approach for the treatment of diabetic nephropathy.

Examining the Potential Formation of Ternary Chromium-Histidine-DNA Complexes and Implications for Their Carcinogenicity

The mutagenic and carcinogenic properties of chromium(VI) complexes have been ascribed to the formation of ternary Cr(III)-small molecule-DNA complexes. As part of these laboratories efforts to establish the structure and properties of discrete binary and ternary adducts of Cr(III) and DNA at a molecular level, the properties of Cr(III)-histidine-DNA complexes formed from Cr(III) were examined. These studies determined the composition of previously described "prereacted" chromium histidinate and reveal the reaction of "prereacted" chromium histidinate with DNA does not form ternary complexes as previously proposed. The products instead are chromium histidinate complexes weakly bound, probably in the minor groove, to DNA. These weakly bound adducts cannot be responsible for the mutagenic and carcinogenic properties ascribed to ternary Cr(III)-histidine-DNA adducts. The results of biological studies where "ternary adducts" of Cr(III), histidine, and DNA were made from "prereacted" chromium histidinate must, therefore, be interpreted with caution.

Serum ferritin as a risk factor for type 2 diabetes mellitus, regulated by liver transferrin receptor 2

OBJECTIVE

The aim of this study was to evaluate the effect of TFR2 on iron storage in type 2 diabetes.

METHODS

A cross-sectional study was conducted among 1938 participants from the Jiangchuan Community of Shanghai. A total of 784 participants with T2DM and 1154 normal participants (non-T2DM) were enrolled in this study. Serum ferritin, fasting blood glucose, postprandial blood glucose, and HbA1C (glycated hemoglobin A1c) levels were determined. Eighteen Wistar male rats were randomly assigned into three groups (n = 6/group): rats in a high-fat diet streptozotocin (HFD+STZ) group were fed with HFD for 4 weeks and intraperitoneally injected with streptozotocin (STZ); rats in a control group were fed with a standard diet for 4 weeks and intraperitoneally injected with buffer; rats in an STZ group were fed with a standard diet for 4 weeks and intraperitoneally injected with streptozotocin. Glucose tolerance test was performed at the end of the study. Blood samples and liver tissues were assessed for liver TFR2, blood glucose, serum ferritin, and iron levels.

RESULTS

The mean serum ferritin level of T2DM participants was significantly higher than that of the control group (227 (140-352) vs 203.5 (130.5-312) ng/mL, P < 0.05). Serum ferritin level was an independent risk factor for T2DM (high ferritin group vs low ferritin group, 1.304 (1.03-1.651), P < 0.05). Diabetic rats showed reduced liver TFR2 levels, with increased serum ferritin levels.

CONCLUSION

T2DM participants exhibited iron disorder with elevated serum ferritin levels. Elevated serum ferritin levels in diabetic rats were accompanied by reduced liver TFR2 levels.

Chromium(III) Glycinate Complex Supplementation Improves the Blood Glucose Level and Attenuates the Tissular Copper to Zinc Ratio in Rats with Mild Hyperglycaemia

The aim of the study was to evaluate the hypoglycaemic potential of supplementary Cr in the form of chromium(III) glycinate (CrGly) in the diabetic model of rats. The experiment was conducted on 40 male Wistar rats, of which 30 were made diabetic by injection of a single dose of streptozotocin (55 mg/kg b.m.), while the remaining 10 rats served as the healthy control. After inducing hyperglycaemia, 2 groups of diabetic rats (10 rats each) were supplemented with Cr either as CrGly or chromium(III) picolinate (CrPic) given orally at a dose of 10 mg/kg diet (about 0.75 mg Cr/kg b.m.) with adequate AIN-93M diet for 7 weeks. At the termination of experiment, all animals were sacrificed to collect blood and internal organs for biochemical assays. Blood biochemical indices and tissular trace element contents (Fe, Zn, Cu, Cr) were measured and compared with the values of the untreated groups. It was found that CrGly significantly decreased blood glucose, total cholesterol, HDL cholesterol and triacylglycerol levels more efficiently than CrPic. Furthermore, both Cr compounds normalized disturbed the serum, renal and cardiac molar Cu/Zn ratio, as well as restored the kidney Zn and Cu levels in rats with hyperglycaemia. Supplementary Cr did not increase the tissular Cr levels in diabetic rats. The study confirmed the hypoglycaemic potential of CrGly in the diabetic model of rats.

Crocin treatment decreased pancreatic atrophy, LOX-1 and RAGE mRNA expression of pancreas tissue in cholesterol-fed and streptozotocin-induced diabetic rats

Objective

Oxidative stress in diabetic mellitus is a consequence of oxidative stress, which plays a critical role in the pathogenesis of diabetic tissue damage. Receptors for advanced glycation end products and for oxidized low-density lipoproteins (LDL) have critical contribution in oxidative tissue damage. The present study investigated whether anti-diabetic effects of Crocin via modulation of mRNA expression of RAGE and LOX-1 receptors in diabetic rats.

Methods

In the current study, high-fat cholesterol (HFC) and streptozotocin (40 mg/kg) used to induce type II diabetes. Experimental groups as follows: (Group 1: control); (Group 2: control treatment [Crocin]); (Group 3: DM [STZ]); (Group 4: DM treatment [STZ + Crocin]); (Group 5; DM + HFC [STZ + HFC]); (Group 6; DM + HFC treatment [STZ + HFC + Crocin]). Crocin (20 mg/kg/day, i.p.) administered in treatment groups for 60 days. Serum glucose and cholesterol levels evaluated on days 5, 30 and 60 after induction of DM. Pancreatic tissue from all group removed on day 60 for histological and RT-PCR analysis.

Results

Application of Crocin significantly decreased serum cholesterol levels on day 60 after induction of DM in diabetic + HFC rats. Moreover, Crocin significantly decreased serum glucose levels on days 30 and 60 both in diabetic and diabetic + HFC rats. Crocin partially prevented the atrophic effects of STZ on both exocrine and endocrine parts of pancreas. Additionally, Crocin significantly decreased LOX-1 and RAGE mRNA expression OF pancreas in diabetic rats.

Conclusion

The current study suggested that Crocin suppressed atrophic change of the pancreas by decrease of LOX-1 and RAGE mRNA expression in diabetic rats.

The Combined Effects of Cr(III) Supplementation and Iron Deficiency on the Copper and Zinc Status in Wistar Rats

The aim of the study was to assess the combined effects of chromium(III) supplementation and iron deficiency on the copper (Cu) and zinc (Zn) status in female rats. The Cr, Fe, Cu and Zn dietary and tissular levels were measured by Atomic Absorption Spectrometry (AAS) method. The data show that chromium(III) supplementation compensated for the negative effects of Fe deficiency on the Cu content but it deepened the effect on Zn levels in the female rats. Detailed data on the status of trace elements and their interactions in healthy subjects and patients with metabolic disorders (e.g. anaemia, diabetes mellitus) are strongly required for effective nutritional and therapeutic strategies.

The combined effects of Cr(III) propionate complex supplementation and iron excess on copper and zinc status in rats

It is suggested that both iron overload and chromium(III) deficiency may be risk factors of diabetes. It seems that both Fe and Cr(III) metabolism as well as copper and zinc metabolism are interrelated. However, the direction of these changes may depend on mutual proportions of these elements in the diet and organism. The aim of the study was to evaluate the combined effects of Cr(III) supplementation with Fe excess on the Cu and Zn status in female rats. Thirty-six healthy rats were divided into 6 experimental groups with different Fe levels in the diet. Groups marked with C (control) contained Fe at the recommended level (45 mg kg^-1). The excess groups (E) contained Fe at 180 mg kg^-1. At the same time the animals were supplemented with Cr(III) of doses 1, 50 and 500 mg kg^-1 of diet. The Cr, Fe, Cu and Zn dietary and tissular contents were measured with the AAS method.The excess Fe in the diet significantly decreased the Cu content in the liver and kidneys, but it increased the spleen Cu level. The Cr(III) supplementary did not affect the tissular Cu levels, regardless of Fe supply with diet. The experimental factors did not have significant interactional effect on the Cu status parameters under study.The Fe excess in the diet reduced the renal and splenic Zn content, but increased the heart Zn content. The Cr(III) supplementation decreased the Zn content in the kidneys. The Zn content in the liver and spleen tended to decrease as the Cr(III) supply in the diet increased. There was no significant interactional effect of Cr(III) supplementation and the Fe excessive supply in diet on the parameters of Zn metabolism in Wistar rats. Iron oversupply disturbed the rat's Cu and Zn status. However, Cr(III) supplementation did not affect the tissular levels of these elements, except the kidney Zn content. Simultaneous supplementation with the Cr(III) propionate complex did not deepen changes in tissular Cu and Zn levels caused by the Fe excess in the diet.

Neurodegenerative Changes in Rat Brain in Streptozotocin Model of Alzheimer's Disease

One of the most common models of sporadic form of Alzheimer's disease is injection of streptozotocin into the lateral ventricles of rat brain. In 3 months after this injection, an increase in the expression of astroglia in the corpus callosum and a decrease in the thickness of the corpus callosum and intensity of its staining with luxol fast blue were observed. This can reflect a decrease in the content of myelinated fibers. In layer V of the sensorimotor cortex, intensive degeneration of neurons was revealed. The lateral ventricles were significantly enlarged and the expression of PSA-NCAM protein, a marker of immature neurons, was reduced in subventricular zone, which can be associated with disturbed neurogenesi.

The protective effects of Crocin on testopathy in fat-fed and streptozotocin-treated diabetic rats: An experimental study

Background

Male hypogonadism is associated with type II diabetes mellitus due to testicular dysfunction. Medicinal plants have received considerable attention for the management of diabetes and its complications.

Objective

The aim of present study was to evaluate the anti-diabetic and protective influence of Crocin on testopathy in diabetic rats.

Materials and Methods

In this experimental study, type II of diabetes mellitus was induced by high-fat diet and low dose of streptozotocin. Male Wistar rats (8 weeks, 150–200 gr, 18 rats; n= 6 per group) were divided into a control group (standard diet), diabetic group (streptozotocin+high-fat diet), and treatment group (High-fat diet+streptozotocin+Crocin at 20 mg/kg/day, i.p. for 60 days). After 60 days, animals were euthanized, testis and epididymis were dissected, and weights of testes and sperm count were analyzed. Hematoxylin-eosin-stained was done for histopathological examination. Blood samples were collected for the assessment of serum glucose and cholesterol.

Results

High-fat diet and streptozotocin significantly increased the serum glucose and cholesterol levels as compared to the control group (p≤ 0. 001). Moreover, there was a significant decrease in the weight of right (p= 0.008) and left testes (p≤ 0. 001) and also the total sperm count (p= 0.023) in the diabetic group compared with the control group. Current results also identified that type II diabetes mellitus induced degeneration in the morphology of seminiferous tubules. Application of Crocin could significantly decrease serum glucose and cholesterol levels (p= 0.003). Furthermore, Crocin treatment significantly increased the weight of the right (p= 0.026) and left (p= 0.014) testes and total sperm count (p= 0.000). Also, Crocin could attenuate the pathological changes of the testes in the treatment group.

Conclusion

Present findings concluded that Crocin treatment improved diabetic testopathy and impairment of seminiferous tubules induced by high-fat diet and streptozotocin.

Comparison of Chromium and Iron Distribution in Serum and Urine among Healthy People and Prediabetes and Diabetes Patients

The effect of chromium (Cr) and iron (Fe) on prevalence of diabetes has received great attention. This study investigated serum and urinary Cr and Fe levels among patients with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), type 1 diabetes (T1D), and type 2 diabetes (T2D) in the Northeast Chinese population. From January 2010 to October 2011, patients with IFG (n=12), IGT (n=15), T1D (n=25), T2D (n=137) and healthy controls (n=50) were enrolled in the First Hospital of Jilin University. Trace elements were detected using an inductively coupled plasma spectrometer. Serum Cr levels decreased in T2D without complications, diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), and diabetic nephropathy (DN) (P<0.05). The urinary Cr level in T1D was the highest of all, which significantly exceeded those of the T2D groups with and without complications. No significant differences of serum Fe levels were found among all groups. The urinary Fe level of T1D was significantly increased (P<0.05). The correlation between serum Cr and serum Fe in T2D was obviously positive (P<0.05). One month of simvastatin therapy exerted no effects on serum or urinary Cr and Fe levels. These results suggest the potential role of Cr and Fe in diabetes should receive attention.

Streptozotocin toxicity in vitro depends on maturity of neurons

Streptozotocin (STZ) is a glucosamine-nitrosourea compound that is particularly toxic to the insulin-producing beta-cells of the pancreas in mammals; it is used for experimental simulation of sporadic Alzheimer's disease by means of intracerebroventricular administration in vivo. Here we show that the application of 3-4 mM STZ to primary culture for 48 h induces neuronal death in immature (2-3 days in vitro) cultures of rat cerebellar granule cells. Mature cultures (7-8 days in vitro) were poorly sensitive to this toxic treatment. Immature cultures demonstrated a high expression of the protein PSA-NCAM, the marker of immature neurons, and they were insensitive to the toxic effect of glutamate. In mature cultures, this protein was poorly expressed, whereas neurons showed a very high sensitivity to the toxic effect of glutamate. Measurements of the concentration of intracellular free calcium ions ([Ca²⁺]_i) showed that the STZ-induced [Ca²⁺]_i increase in young neurons was six times higher than that in mature neurons. Our results show that STZ is very toxic for immature neurons and probably it can significantly impair neurogenesis.

Effects of the Oral Administration of K2Cr2O7 and Na2SeO3 on Ca, Mg, Mn, Fe, Cu, and Zn Contents in the Heart, Liver, Spleen, and Kidney of Chickens

This study aimed to investigate the effects of selenium on the ion profiles in the heart, liver, spleen, and kidney through the oral administration of hexavalent chromium. Approximately 22.14 mg/kg b.w. K₂Cr₂O₇ was added to water to establish a chronic poisoning model. Different selenium levels (0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg Na₂SeO₃/kg b.w.) around the safe dose were administered to the experimental group model. Ca, Mg, Mn, Fe, Cu, and Zn were detected in the organs through flame atomic absorption spectrometry after these organs were exposed to K₂Cr₂O₇ and Na₂SeO₃ for 14, 28, and 42 days. Results showed that these elements exhibited various changes. Ca contents declined in the heart, liver, and spleen. Ca contents also decreased on the 28th day and increased on the 42nd day in the kidney. Mn contents declined in the heart and spleen but increased in the kidney. Mn contents also decreased on the 28th day and increased on the 42nd day in the liver. Cu contents declined in the heart and spleen. Cu contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Zn contents declined in the heart and spleen. Zn contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Fe contents decreased in the heart and liver. Fe contents increased on the 28th day and decreased on the 42nd day in the spleen and kidney. Mg contents did not significantly change in these organs. Appropriate selenium contents enhanced Mn and Zn contents, which were declined by chromium. Conversely, appropriate selenium contents reduced Ca, Fe, and Cu contents, which were increased by chromium. In conclusion, the exposure of chickens to K₂Cr₂O₇ induced changes in different trace elements, and Na₂SeO₃ supplementation could alleviate this condition.

Combined oral supplementation of chromium picolinate, docosahexaenoic acid, and boron enhances neuroprotection in rats fed a high-fat diet

Background/aim: A novel complex of a nutritional supplement (CDB) contains chromium picolinate (CrPic), phosphatidylserine (PS), docosahexaenoic acid (DHA), and boron (B). The present study aimed to investigate the effects of CDB on the metabolic profile and memory acquisition in rats fed a high-fat diet (HFD). Materials and methods: Male Wistar rats were divided into six groups and received either a regular diet or HFD supplemented with or without different levels of CDB (0, 11, or 22 mg/kg BW). Results: Rats fed the HFD had greater glucose, insulin, lipid profile, and serum malondialdehyde concentrations, but lower serotonin and tryptophan in the serum and brain and lower Cr concentrations in serum, kidney, brain, and liver (P < 0.0001). CDB complex supplementation reversed all the effects, and the reversal effect was more pronounced with HFD for some parameters. Latency was less (P < 0.05) but probe was greater (P < 0.0001) for rats fed a regular diet. Increasing CDB complex levels in the diets resulted in a linear decrease in latency (P < 0.0002) but a linear increase in probe (P < 0.0002). Conclusion: Findings of the present work indicate that the CDB complex could be considered as an alternative treatment for preventing certain metabolic diseases and improving neurological functions, such as learning and memory.

The Effects of Supplementary Cr3 (Chromium(III) Propionate Complex) on the Mineral Status in Healthy Female Rats

More and more people use food supplements for various reasons, e.g. to prevent mineral deficiency and diseases (e.g. osteoporosis, diabetes, anaemia). Supplements containing Cr(III) are purchased primarily for weight loss and antidiabetic effects. The aim of this study was to evaluate the effects of supplementary Cr3 {chromium(III) propionate complex, [Cr3O(O2CCH2CH3)6(H2O)3]NO3)} on the mineral status in female Wistar rats. The study was carried out on 30 female Wistar rats, divided into five groups (six animals in each): a control group and test groups fed Cr3 supplemented diets with 100, 200, 500 and 1000 mg Cr · kg-1 diet (equivalent to 10, 20, 50 and 100 mg Cr ·kg-1 body mass (b.m.) per day) given as Cr3 for 4 weeks. Supplementary Cr3 increased the Cr content in tissues in a dose-dependent manner. High dietary doses of Cr3, 20 and 100 mg Cr · kg-1 b.m., increased the Cu content in the liver and spleen as well as the Zn content in the kidneys but decreased the liver Ca content. Doses of 50-100 mg Cr ·kg-1 b.m. decreased the serum Fe concentration and the Fe content in the liver and kidneys. Supplementation with Cr3 at doses of 10 and 100 mg Cr ·kg-1 b.m. did not affect the Mg content in the rats' tissues. In conclusion, high dietary doses of Cr3 (10 and 100 mg Cr· kg-1 b.m.) given for 4 weeks affected the mineral status of Fe, Zn, Cu and Ca in the tissues of healthy female Wistar rats.

Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency

Iron (Fe) deficiency is considered as the most common nutritional deficiency. Iron deficiency is usually associated with low Fe intake, blood loss, diseases, poor absorption, gastrointestinal parasites, or increased physiological demands as in pregnancy. Nutritional Fe deficiency is usually treated with Fe tablets, sometimes with Fe-containing multimineral tablets. Trace element interactions may have a significant impact on Fe status. Existing data demonstrate a tight interaction between manganese (Mn) and Fe, especially in Fe-deficient state. The influence of Mn on Fe homeostasis may be mediated through its influence on Fe absorption, circulating transporters like transferrin, and regulatory proteins. The existing data demonstrate that the influence of zinc (Zn) on Fe status may be related to their competition for metal transporters. Moreover, Zn may be involved in regulation of hepcidin production. At the same time, human data on the interplay between Fe and Zn especially in terms of Fe-deficiency and supplementation are contradictory, demonstrating both positive and negative influence of Zn on Fe status. Numerous data also demonstrate the possibility of competition between Fe and chromium (Cr) for transferrin binding. At the same time, human data on the interaction between these metals are contradictory. Therefore, while managing hypoferremia and Fe-deficiency anemia, it is recommended to assess the level of other trace elements in parallel with indices of Fe homeostasis. It is supposed that simultaneous correction of trace element status in Fe deficiency may help to decrease possible antagonistic or increase synergistic interactions.

Anti-diabetic effects of Inonotus obliquus polysaccharides-chromium (III) complex in type 2 diabetic mice and its sub-acute toxicity evaluation in normal mice

Polysaccharides are important bioactive ingredients from Inonotus obliquus. This study aimed to synthesize and characterize a novel I. obliquus polysaccharides-chromium (III) complex (UIOPC) and investigate the anti-diabetic effects in streptozotocin (STZ) induced type 2 diabetes mellitus (T2DM) mice and sub-acute toxicity in normal mice. The molecular weight of UIOPC was about 11.5 × 10 ⁴ Da with the chromium content was 13.01% and the chromium was linked with polysaccharides through coordination bond. After treatment of UIOPC for four weeks, the body weight, fasting blood glucose (FBG) levels, plasma insulin levels of the diabetic mice were significantly reduced when compared with those of the diabetic mice (p < 0.05). The results on serum profiles and antioxidant enzymes activities revealed that UIOPC had a positive effect on hypoglycemic and antioxidant ability. Histopathology results showed that UIOPC could effectively alleviate the STZ-lesioned tissues in diabetic mice. Furthermore, high dose administration of UIOPC had no obviously influence on serum profiles levels and antioxidant ability of the normal mice and the organ tissues maintained organized and integrity in the sub-acute toxicity study. These results suggested that UIOPC might be a good candidate for the functional food or pharmaceuticals in the treatment of T2DM.

POTENTIAL ADMINISTRATION OF LIPOIC ACID AND COENZYME Q AGAINST ADIPOGENSIS: TARGET FOR WEIGHT REDUCTION

Background:

Body overweight and obesity were considered as a risk factor for many systemic diseases as diabetic hypertension, cardiovascular diseases, and some cancers. The lipoic acid and Co Q are considered as coenzymes needed for enhancement metabolic rate. The goal of this study is to evaluate the anti-obese effect of lipoic acid alone or combined with Co-Q in rats.

Materials and Methods:

Ninety male albino rats (100-150g) were used in this study, divided into six groups (15 each). Group I: Normal rats fed normal diet. Group II: Rats fed high fat diet (HFD). Group III: Rats fed HFD were given lipoic acid (10 μg/kg b w/day) intra-gastric by stomach tube. Group IV: Rats fed HFD were given Co-Q (10 μg/kg b.w/day) intra-gastric. Group V: Rats fed HFD were given lipoic acid (50 mg/kg b w/day) and Co-Q (10 μg/kg b. w/day). Group VI: Rats were given orlistat intra-gastric (10 mg/kg b w/day) as positive control for 6 weeks. Serum was subjected for determination of lipid profile, liver function tests atherogenic factor and lipoprotein lipase.

Results:

It was found that treatment with lipoic acid or Co-Q or combined showed increase in the activity of lipoprotein lipase (P < 0.001) and reduction of atherogenic effect and obesity index (P <0.001). The effect of combined gives good results than orlistat or individual treatment.

Conclusion:

lipoic acid combined with Co-Q increase fat oxidation and prevent fat accumulation. The consumption of lipoic acid daily promotes fat oxidation and prevents its accumulation in visceral tissues. Further studies should be carried out to examine the mechanistic signals of these nutrients that helps in weight management.

Element-tracing of mineral matters in Dendrobium officinale using ICP-MS and multivariate analysis

Rare studies have been performed to trace the mineral elements in Dendrobium officinale. In this study, we aim to trace the mineral elements in D. officinale collected from ten geographical locations in China. ICP-MS system was used for simultaneous determination of mineral elements. Principal component analysis was performed using the obtained data in the quantification of mineral contents. Cluster analysis was performed using the Ward's method. Several of essential microelments were detected in D. officinale, including ferrum (Fe), manganese (Mn), zinc (Zn), chromium (Cr), nickel (Ni) and vanadium (V). Among these elements, three elements (i.e. Fe, Mn and Zn) were highly and simultaneously detected in the D. officinale collected from the ten locations. The level of Ni was positively associated with that of Zn (r = 0.986, P < 0.01). The level of titanium (Ti) was positively associated with that of V (r = 0.669, P < 0.05), and negatively associated with Cr (r = -0.710, P < 0.05). In addition, the level of Mn was positively associated with that of barium (r = 0.749, P < 0.05). Further, the level of Fe was positively associated with that of Ni (r = 0.664, P < 0.05), Zn (r = 0.742, P < 0.05), and rare earth elements (r = 0.847, P < 0.01), respectively. Three eigenvalues explained about 86.60 % of the total variance, which contributed significantly to the explanation of cumulative variance. Cluster analysis indicated the cultivars were categorized into 3 clusters. Ni, Zn, Fe, Cr, Ti and rare earth elements were designated as the characteristic elements. Cultivars collected from Yulin, Menghai, and Shaoguan ranked the top 3 in the comprehensive scores, indicating the content of the mineral elements was comparatively higher in these locations.

Effects of Oral Administration of CrCl3 on the Contents of Ca, Mg, Mn, Fe, Cu, and Zn in the Liver, Kidney, and Heart of Chicken

This study aimed to investigate the effects of oral administration of trivalent chromium on the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney. Different levels of 1/8, 1/4, and 1/2 LD50 (LD50 = 5000 mg/kg body mass) CrCl3 milligrams per kilogram body mass daily were added into the water to establish the chronic poisoning model. Ca, Mg, Mn, Fe, Cu, and Zn were detected with the flame atomic absorption spectrometry in the organs exposed 14, 28, and 42 days to CrCl3, respectively. Results showed that Cr was accumulated in the heart, liver, and kidney significantly (P < 0.05) with extended time and dose. The contents of Ca and Fe increased, whereas those of Mg, Mn, Cu, and Zn decreased in the heart, liver, and kidney of each treated group, which had a dose- and time-dependent relationship, but the contents of Mg and Zn in the heart took on a fluctuated change. These particular observations were different from those in the control group. In conclusion, the oral administration of CrCl3 could change the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney, which may cause disorders in the absorption and metabolism of the metal elements of chickens.

The Effects of High Dietary Doses of Chromium(III) Complex with Propionic Acid on Nutritional and Selected Blood Indices in Healthy Female Rats

People taking dietary supplements are usually determined to lose weight, supplement nutrition or reduce the risk of illness and negative effects of their state of health. Chromium(III) supplementation influence body composition and mass, glucose and lipid metabolism and it enhance insulin action. This fact could be of general interest because diabetes mellitus is an increasing health problem in many countries. The study describes the effects of high dietary doses of chromium(III) complex with propionic acid [Cr3] (from 100 to 1000 mg Cr · kg(-1) diet) on the organisms of healthy female rats, with special regard to overall nutritional, carbohydrate, lipid and blood biochemical and morphological and haematological indices. The study was carried out on 30 10-week-old female Wistar rats, which were divided into five equal groups (six animals in each): the control group and four groups of tested animals which had free access to the diet supplemented with 100, 200, 500 and 1000 mg Cr · kg(-1) (equivalent of 10, 20, 50 and 100 mg Cr · kg body weight (b.w.) · day(-1)), given as [Cr3O(O2CCH2CH3)6(H2O)3]⋅NO3, also known as Cr3, for 4 weeks. There were no significant differences in body mass gains, feeding efficiency ratio, internal organ masses or blood serum glucose concentrations, except for some changes in the serum triglycerides concentration, which decreased in the rats that received 500 and 1000 mg Cr · kg(-1) diet, as opposed to the group treated with 200 mg Cr · kg(-1) diet. The dietary supplementation of Cr3 for 4 weeks at doses of 100 to 1000 mg Cr · kg(-1) diet did not affect overall nutritional indices and most blood biochemical, morphological and haematological indices.

Chromium supplementation improved post-stroke brain infarction and hyperglycemia

Hyperglycemia is common after acute stroke and is associated with a worse outcome of stroke. Thus, a better understanding of stress hyperglycemia is helpful to the prevention and therapeutic treatment of stroke. Chromium is an essential nutrient required for optimal insulin activity and normal carbohydrate and lipid metabolism. Beyond its nutritional effects, dietary supplement of chromium causes beneficial outcomes against several diseases, in particular diabetes-associated complications. In this study, we investigated whether post-stroke hyperglycemia involved chromium dynamic mobilization in a rat model of permanent focal cerebral ischemia and whether dietary supplement of chromium improved post-stroke injury and alterations. Stroke rats developed brain infarction, hyperglycemia, hyperinsulinemia, glucose intolerance, and insulin resistance. Post-stroke hyperglycemia was accompanied by elevated secretion of counter-regulatory hormones including glucagon, corticosterone, and norepinephrine, decreased insulin signaling in skeletal muscles, and increased hepatic gluconeogenesis. Correlation studies revealed that counter-regulatory hormone secretion showed a positive correlation with chromium loss and blood glucose increased together with chromium loss. Daily chromium supplementation increased tissue chromium levels, attenuated brain infarction, improved hyperglycemia, and decreased plasma levels of glucagon and corticosterone in stroke rats. Our findings suggest that stroke rats show disturbance of tissue chromium homeostasis with a net loss through urinary excretion and chromium mobilization and loss might be an alternative mechanism responsible for post-stroke hyperglycemia.

The Technical and Financial Effects of Parenteral Supplementation with Selenium and Vitamin E during Late Pregnancy and the Early Lactation Period on the Productivity of Dairy Cattle

This study aimed to determine the effects of parenteral selenium (Se) and vitamin E supplementation on economic impact, milk yield, and some reproductive parameters in high-yield dairy cows in the dry period and in those at the beginning of lactation. At the beginning of the dry period, cows (n = 323) were randomly divided into three groups as follows: Treatment 1 (T1), Treatment 2 (T2), and Control (C). Cows in group T1 received this preparation 21 days before calving and on calving day, and cows in group T2 received it only on calving day. The cows in the control group did not receive this preparation. Supplementation with Se increased Se serum levels of cows treated at calving day (p<0.05). Differences in milk yield at all weeks and the electrical conductivity values at the 8th and 12th weeks were significant (p<0.05). Supplementation with Se and Vitamin E decreased the incidence of metritis, the number of services per conception and the service period, but had no effects on the incidence of retained fetal membrane. A partial budgeting analysis indicated that Se supplementation was economically profitable; cows in group T1 averaged 240.6$ per cow, those in group T2 averaged 224.6$ per cow. Supplementation with Se and Vitamin E has been found to increase serum Se levels, milk yield, and has positive effects on udder health by decreasing milk conductivity values and incidence of sub-clinical mastitis.

Curcumin protects renal tubular epithelial cells from high glucose-induced epithelial-to-mesenchymal transition through Nrf2-mediated upregulation of heme oxygenase-1

Curcumin has been observed to exhibit an anti-fibrotic effect in the liver, lung and gallbladder. However, the mechanisms underlying the cytoprotective effects of curcumin remain to be elucidated. The epithelial-to-mesenchymal transition (EMT) of mature tubular epithelial cells in the kidney is considered to contribute to the renal accumulation of matrix proteins associated with diabetic nephropathy. The EMT is also closely associated with the progression of renal interstitial fibrosis and oxidative stress. This process may occur through abrogation of high glucose (HG)-induced oxidative stress via activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) in kidney tubular epithelial cells. In the present study, the effect of curcumin on HG-induced EMT in the NRK-52E normal rat kidney tubular epithelial cell line was investigated, and whether the effect of curcumin was mediated by the induction of Nrf2 and HO-1 expression was examined. The present study revealed that curcumin was able to prevent events associated with EMT, including the downregulation of E-cadherin and the increased expression of α-smooth muscle actin. Further analysis revealed that the expression levels of Nrf2 and HO-1 protein were elevated to a greater extent in the curcumin pretreated NRK-52E cells compared with those of the control. Notably, knockdown of Nrf2 with small interfering RNA prevented the curcumin-induced elevation in expression of HO-1 and the associated anti-fibrotic effects. In conclusion, the present findings suggested that curcumin may be significant in cellular antioxidant defense, through the activation of Nrf2 and HO-1, thereby protecting the NRK-52E cells from HG-induced EMT.

Hypoglycemic activity and acute oral toxicity of chromium methionine complexes in mice

The hypoglycemic activity of chromium methionine (CrMet) in alloxan-induced diabetic (AID) mice was investigated and compared with those of chromium trichloride hexahydrate (CrCl3·6H2O) and chromium nicotinate (CrNic) through a 15-day feeding experiment. The acute oral toxicity of CrMet was also investigated in ICR (Institute for Cancer Research) mice by a single oral gavage. The anti-diabetic activity of CrMet was explored in detail from the aspects of body weight (BW), blood glucose, triglyceride, total cholesterol, liver glycogen levels, aspartate transaminase (AST) and alanine transaminase (ALT) levels. The obtained results showed that CrMet had beneficial effects on glucose and lipid metabolism, and might possess hepatoprotective efficacy for diabetes. Daily treatment with 500 and 1000μg Cr/kg BW of CrMet in AID mice for 15 days indicated that this low-molecular-weight organic chromium complex had better bioavailability and more beneficial effects on diabetics than CrCl3·6H2O. CrMet also had advantage over CrNic in the control of AST and ALT activities. Acute toxicity studies revealed that CrMet had low toxicity potential and relatively high safety margins in mice with the LD50 value higher than 10.0g/kg BW. These findings suggest that CrMet might be of potential value in the therapy and protection of diabetes.

Is chromium pharmacologically relevant?

Recent research, combined with reanalysis of previous results, has revealed that chromium can no longer be considered an essential trace element. Clinical studies are ambiguous at best as to whether Cr has a pharmacological effect in humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. Studies on the effects of Cr on rat models of diabetes are reviewed herein and suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr.

Effects of exposure to dietary chromium on tissue mineral contents in rats fed diets with fiber

This study evaluated the effects of diets with fiber (cellulose and/or pectin) supplemented with chromium(III) on homeostasis of selected minerals in femurs, thigh muscles, livers, and kidneys of rats. For 6 weeks, male rats were fed experimental diets: a fiber-free diet (FF), a diet containing 5% cellulose (CEL), 5% pectin (PEC), or 2.5% cellulose and 2.5% pectin (CEL+PEC). These diets had 2.53 or 0.164 mg Cr/kg diet. The tissue levels of Ca, Mg, Zn, Fe, and Cr were determined by using atomic absorption spectrometry. Supplementing diets with Cr resulted in significantly higher Cr levels in the femurs of rats fed the CEL diet and significantly higher Cr and Fe levels in the rats fed the CEL+PEC diet compared to the rats fed FF diet. Muscle Ca content was significantly lower in the rats fed the CEL+PEC+Cr diet compared to the rats fed FF+Cr diet. The rats consuming the PEC+Cr diet had the highest liver Cr content. The highest kidney Zn content was observed in the rats fed diets containing Cr and one type of fiber. These results indicate that diets containing chromium at elevated dose and fiber have a significant effect on the mineral balance in rat tissues.

Hepcidin is directly regulated by insulin and plays an important role in iron overload in streptozotocin-induced diabetic rats

Iron overload is frequently observed in type 2 diabetes mellitus (DM2), but the underlying mechanisms remain unclear. We hypothesize that hepcidin may be directly regulated by insulin and play an important role in iron overload in DM2. We therefore examined the hepatic iron content, serum iron parameters, intestinal iron absorption, and liver hepcidin expression in rats treated with streptozotocin (STZ), which was given alone or after insulin resistance induced by a high-fat diet. The direct effect of insulin on hepcidin and its molecular mechanisms were furthermore determined in vitro in HepG2 cells. STZ administration caused a significant reduction in liver hepcidin level and a marked increase in intestinal iron absorption and serum and hepatic iron content. Insulin obviously upregulated hepcidin expression in HepG2 cells and enhanced signal transducer and activator of transcription 3 protein synthesis and DNA binding activity. The effect of insulin on hepcidin disappeared when the signal transducer and activator of transcription 3 pathway was blocked and could be partially inhibited by U0126. In conclusion, the current study suggests that hepcidin can be directly regulated by insulin, and the suppressed liver hepcidin synthesis may be an important reason for the iron overload in DM2.

Supplementary chromium(III) propionate complex does not protect against insulin resistance in high-fat-fed rats

Improper eating habits such as high-fat or high-carbohydrate diets are responsible for metabolic changes resulting in impaired glucose tolerance, hyperinsulinemia, insulin resistance, and ultimately diabetes. Although the essentiality of trivalent chromium for humans has been recently questioned by researchers, pharmacological dosages of this element can improve insulin sensitivity in experimental animals and diabetic subjects. The aim of the study was to assess the preventive potential of the supplementary chromium(III) propionate complex (CrProp) in rats fed a high-fat diet. The experiment was conducted on 32 male Wistar rats divided into four groups and fed the following diets: the control (C, AIN-93G), high-fat diets (HF, 40% energy from fat), and a high-fat diet supplemented with CrProp at dosages of 10 and 50 mg Cr/kg diet (HF + Cr10 and HF + Cr50, respectively). After 8 weeks, high-fat feeding led to an increased body mass, hyperinsulinemia, insulin resistance, a decreased serum urea concentration, accumulation of lipid droplets in hepatocytes, and increased renal Fe and splenic Cu contents. Supplementary CrProp in both dosages did not alleviate these changes but increased renal Cr content and normalized splenic Cu content in high-fat-fed rats. Supplementary CrProp does not prevent the development of insulin resistance in rats fed a high-fat diet.

Changes in iron metabolism and oxidative status in STZ-induced diabetic rats treated with bis(maltolato) oxovanadium (IV) as an antidiabetic agent

The role of vanadium as a micronutrient and hypoglycaemic agent has yet to be fully clarified. The present study was undertaken to investigate changes in the metabolism of iron and in antioxidant defences of diabetic STZ rats following treatment with vanadium. Four groups were examined: control; diabetic; diabetic treated with 1 mgV/day; and Diabetic treated with 3 mgV/day. The vanadium was supplied in drinking water as bis(maltolato) oxovanadium (IV) (BMOV). The experiment had a duration of five weeks. Iron was measured in food, faeces, urine, serum, muscle, kidney, liver, spleen, and femur. Superoxide dismutase, catalase, NAD(P)H: quinone-oxidoreductase-1 (NQO1) activity, and protein carbonyl group levels in the liver were determined. In the diabetic rats, higher levels of Fe absorbed, Fe content in kidney, muscle, and femur, and NQO1 activity were recorded, together with decreased catalase activity, in comparison with the control rats. In the rats treated with 3 mgV/day, there was a significant decrease in fasting glycaemia, Fe content in the liver, spleen, and heart, catalase activity, and levels of protein carbonyl groups in comparison with the diabetic group. In conclusion BMOV was a dose-dependent hypoglycaemic agent. Treatment with 3 mgV/day provoked increased Fe deposits in the tissues, which promoted a protein oxidative damage in the liver.

Chromium modulates expressions of neuronal plasticity markers and glial fibrillary acidic proteins in hypoglycemia-induced brain injury

AIMS

This experiment investigated if chromium (Cr) as Cr-histidinate (CrHis) and Cr29 picolinate (CrPic) have a protective role in rats with hypoglycemia-induced brain injury, assessed by neuronal plasticity and regeneration potential.

MAIN METHODS

Male Sprague-Dawley rats were prospectively divided into 2 groups: control and hypoglycemic (induced by insulin administration, 15U/kg, i.p., n=56). Hypoglycemic rats were then received randomly 1) none, 2) dextrose (on the day of sampling), 3) CrHis, or 4) CrPic. Cr-chelates were delivered via drinking water (providing 8μg elemental Cr per day) for one week prior to the hypoglycemia induction. The expressions of neuroplasticity markers [neural cell adhesion molecule (NCAM), growth-associated protein-43 (GAP-43), glial fibrillary acidic protein (GFAP)], glucose transporters (GLUT), and nuclear transcription proteins [nuclear factor-kappa (NF-κB), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and 4-hydroxyl nonenal (HNE)] were determined using Western blot.

KEY FINDINGS

Hypoglycemia caused increases in the expressions of GLUT-1, GLUT-3, GFAP, NF-κB and HNE and decreases in the expression of NCAM's, GAP-43 and Nrf2 in the hippocampus, cerebellum, and cortex. Cr-chelates suppressed expressions of GLUTs, GFAP, NF-κB and HNE expressions and enhanced expressions of NCAM, GAP-43 and Nrf2, which were more notable for CrHis than for CrPic.

SIGNIFICANCE

In conclusion, hypoglycemia leads to cerebral injury and Cr-chelates, particularly CrHis have protective and regeneration potential in cerebral tissues through modulating neuroplasticity markers and nuclear transcription proteins as well as facilitating glucose transporters.

Comparison of tissue metal concentrations in Zucker lean, Zucker obese, and Zucker diabetic fatty rats and the effects of chromium supplementation on tissue metal concentrations

Diabetes results in several metabolic changes, including alterations in the transport, distribution, excretion, and accumulation of metals. While changes have been examined in several rat models of insulin resistance and diabetes, the metal ion concentrations in the tissues of Zucker lean, Zucker obese (an insulin resistance and early stage diabetes model), and Zucker diabetic fatty (ZDF, a type 2 diabetes model) have not previously been examined in detail. The concentration of Cu, Zn, Fe, Mg, and Ca were examined in the liver, kidney, heart and spleen, and Cr concentration in the liver and kidney of these rats were examined. Zucker obese rats have a reduction in the concentration of Cu, Zn, Fe, Mg in the liver compared to ZDF and/or lean Zucker rats, presumably as a result of the increased fat content of the liver of the obese rats. ZDF rats have increased concentrations of kidney Cu compared to the lean rats, while kidney Ca concentrations are increased in the Zucker obese rats. Spleen Fe concentrations are decreased in Zucker obese rats compared to the lean rats. No effects on metal concentrations in the heart were observed between the lean, obese, and ZDF rats, and no effects on Cr concentrations were identified. Cr(III) complexes have previously been shown to have beneficial effects on the signs of insulin resistance in Zucker obese and ZDF rats. The effects of daily gavage administration of chromium picolinate ([Cr(pic)(3)]) (1 mg Cr/kg body mass), CrCl(3) (1 mg Cr/kg body mass), and Cr3 ([Cr(3)O(propionate)(6)(H(2)O)(3)](+)) (33 μg and 1 mg Cr/kg body mass) on metal concentrations in these tissues were examined. Treatment with CrCl(3) and Cr3, but not [Cr(pic)(3)], at 1 mg Cr/kg resulted in a statistically significant accumulation of Cr in the kidney of lean and obese but not ZDF rats but resulted in lowering the elevated levels of kidney Cu in ZDF rats, suggesting a beneficial effect on this symptom of type 2 diabetes.

Alterations in kidney tissue following zinc supplementation to STZ-induced diabetic rats

Diabetes mellitus is a chronic disease characterized by anomalies forming in carbohydrate, lipid, protein metabolisms and the incidence of this disease varies widely throughout the world. Zinc is an important element which is essential for life and is present in nature. In this study, the animals were divided into four groups. These groups were named as untreated; zinc sulfate; streptozotocin (STZ); STZ and zinc sulfate. STZ (65 mg/kg) was dissolved in a freshly prepared 0.01 M pH 4.5 citrate buffer and given with intraperitoneal injection in a single dose. Zinc sulfate (100mg/kg) was dissolved in distilled water and given to the animals by gavage at a daily dose for 60 days. The rats were sacrificed under ether anesthesia. This study was aimed to investigate histological and biochemical changes of zinc supplementation on the kidney tissue in STZ-induced diabetic rats. In the current study, histological and histochemical observations showed that the occurred degenerative changes decreased after giving zinc in the kidney tissue of diabetic group. Kidney glutathione (GSH) levels decreased and lipid peroxidation (LPO), nonenzymatic glycosylation (NEG), urea and creatinine levels increased in diabetic rats. GSH levels increased, while LPO, NEG, urea and creatinine levels decreased in the kidney with administration of zinc to diabetic rats. As a result, we observed curative effects of zinc given to diabetic rats. We can say that zinc may be an important antioxidant for the treatment of secondary complications of diabetes in kidney tissue.

Chromium: is it essential, pharmacologically relevant, or toxic?

Over fifty years ago, the element chromium (as the trivalent ion) was proposed to be an essential element for mammals with a role in maintaining proper carbohydrate and lipid metabolism. Evidence for an essential role came from dietary studies with rodents, studies on the effects of chromium on subjects on total parenteral nutrition, and studies of the absorption and transport of chromium. Over the next several decades, chromium-containing nutritional supplements became so popular for weight loss and muscle development that sales were second only to calcium among mineral supplements. However, the failure to identify the responsible biomolecules(s) that bind chromium(III) and their mode of action, particularly a postulated species named glucose tolerance factor or GTF, resulted in the status of chromium being questioned in recent years, such that the question of its being essential needs to be formally readdressed. At the same time as chromium(III)'s popularity as a nutritional supplement was growing, concerns over its safety appeared. While chromium has been conclusively shown not to have beneficial effects on body mass or composition and should be removed from the list of essential trace elements, chromium(III) compounds are generally nontoxic and have beneficial pharmacological effects in rodents models of insulin insensitivity, although human studies have not conclusively shown any beneficial effects. Mechanisms have been proposed for these pharmacological effects, but all suffer from a lack of consistent supporting evidence.

Effects of combined dietary chromium(III) propionate complex and thiamine supplementation on insulin sensitivity, blood biochemical indices, and mineral levels in high-fructose-fed rats

Insulin resistance is the first step in glucose intolerance and the development of type 2 diabetes mellitus, thus effective prevention strategies should also include dietary interventions to enhance insulin sensitivity. Nutrients, such as microelement chromium(III) and thiamine, play regulatory roles in carbohydrate metabolism. The objective of this study was to evaluate the insulin-sensitizing potential of the combined supplementary chromium(III) propionate complex (CrProp) and thiamine in insulin resistance animal model (rats fed a high-fructose diet). The experiment was carried out on 40 nine-week-old male Wistar rats divided into five groups (eight animals each). Animals were fed ad libitum: the control diet (AIN-93 M) and high-fructose diets with and without a combination of two levels of CrProp (0.1 and 1 mg Cr/kg body mass/day) and two levels of thiamine (0.5 and 10 mg/kg body mass/day) for 8 weeks. At the end of the experiment rats were sacrificed to collect blood and internal organs for analyses of blood biochemical and hematologic indices as well as tissular microelement levels that were measured using appropriate methods. It was found that both supplementary CrProp and thiamine (given alone) have significant insulin-sensitizing and moderate blood-lipid-lowering properties, while the combined supplementation with these agents does not give synergistic effects in insulin-resistant rats. CrProp given separately increased kidney Cu and Cr levels, while thiamine alone increased hepatic Cu contents and decreased renal Zn and Cu contents.

Hepatoprotective activity of CrPic against alloxan-induced hepatotoxicity in mice

This study focused on oxidation hepatic injury induced by alloxan treatment in mice and the hepatoprotective effect of chromium picolinate (CrPic) against such injury. The mice were randomly divided into three groups (control, alloxan, and CrPic). The CrPic mice were given Cr(3+) (40 μg/kg bm/day), and other mice were given equivalent intragastric doses of water every day. After 4 weeks, the groups alloxan and CrPic were treated with alloxan (40 mg/kg/day) through intraperitoneal injection daily for 6 days. Biochemical and enzymatic characteristics were assayed in these animals. The MDA levels of the control and CrPic groups were 33.93 % and 28.45 % lower, respectively, than that of the alloxan group. The levels of superoxide dismutase (SOD) and GSH-Px in the alloxan group were 15.30 % and 15.69 % higher, respectively,than those of the control group. Both the SOD and GSH-Px levels of the control and CrPic groups were about the same. Levels of CuZnSOD mRNA of the control and CrPic groups were 0.27 fold and 1.03 fold lower than in the alloxan group. The transcription levels of GSH-Px in the control and CrPic groups were 1.57 fold and 0.99 fold below those of the alloxan group. These results show that significant hepatic injury can be induced by alloxan treatment in mice; in addition, CrPic may be useful in health products meant to treat human liver disease.

Chromium picolinate modulates serotonergic properties and carbohydrate metabolism in a rat model of diabetes

Chromium picolinate (CrPic) has shown both antidepressant and antidiabetic properties. In this study, the effects of CrPic on serotonergic properties and carbohydrate metabolism in diabetic rats were evaluated. Sixty male Sprague-Dawley rats were divided into four groups. (1) The control group received only standard diet (8 % fat). (2) The CrPic group was fed standard diet and CrPic (80 μg CrPic per kilogram body mass (b.m.)/day), for 10 weeks (microgram/kilogram b.m./day). (3) The HFD/STZ group fed a high-fat diet (HFD, 40 % fat) for 2 weeks and then received streptozotocin (STZ, 40 mg/kg, i.p.) (i.v.) HFD-STZ-CrPic group treated as the previous group and then were administered CrPic. CrPic administration to HFD/STZ-treated rats increased brain chromium levels and improved all measurements of carbohydrate metabolism and serotonergic properties (P<0.001). CrPic also significantly increased levels of insulin, tryptophan, and serotonin (P<0.001) in the serum and brain, and decreased cortisol levels in the serum (P<0.01). Except chromium levels, no significant effect of CrPic supplementation was detected on the overall measured parameters in the control group. CrPic administration was well tolerated without any adverse events. The results support the use of CrPic supplementation which improves serotonergic properties of brain in diabetes.

Syzygium cumini ameliorates insulin resistance and β-cell dysfunction via modulation of PPAR, dyslipidemia, oxidative stress, and TNF-α in type 2 diabetic rats

Syzygium cumini (SC) is well known for its anti-diabetic potential, but the mechanism underlying its amelioration of type 2 diabetes is still elusive. Therefore, for the first time, we investigated whether SC aqueous seed extract (100, 200, or 400 mg/kg) exerts any beneficial effects on insulin resistance (IR), serum lipid profile, antioxidant status, and/or pancreatic β-cell damage in high-fat diet / streptozotocin-induced (HFD-STZ) diabetic rats. Wistar albino rats were fed with HFD (55% of calories as fat) during the experiment to induce IR and on the 10th day were injected with STZ (40 mg/kg, i.p.) to develop type 2 diabetes. Subsequently, after confirmation of hyperglycemia on the 14th day (fasting glucose level > 13.89 mM), diabetic rats were treated with SC for the next 21 days. Diabetic rats showed increased serum glucose, insulin, IR, TNF-α, dyslipidemia, and pancreatic thiobarbituric acid-reactive substances with a concomitant decrease in β-cell function and pancreatic superoxide dismutase, catalase, and glutathione peroxidase antioxidant enzyme activities. Microscopic examination of their pancreas revealed pathological changes in islets and β-cells. These alterations reverted to near-normal levels after treatment with SC at 400 mg/kg. Moreover, hepatic tissue demonstrated increased PPARγ and PPARα protein expressions. Thus, our study demonstrated the beneficial effect of SC seed extract on IR and β-cell dysfunction in HFD-STZ-induced type 2 diabetic rats.

Effects of zinc supplementation on the element distribution in kidney tissue of diabetic rats subjected to acute swimming

In this study, we report the effect of zinc supplementation on the distribution of elements in kidney tissue of diabetic rats subjected to acute swimming exercise. Diabetes was induced by two subcutaneous injections of 40 mg/kg of streptozotocin within a 24-h period. Zinc was given intraperitoneally at a dose of 6 mg/kg per day for a period of 4 weeks. The rats (n = 80) were equally divided into eight study groups: controls, zinc-supplemented, swimming, diabetic, zinc-supplemented diabetic, zinc-supplemented swimming, diabetic swimming, and zinc-supplemented diabetic swimming. The levels of lead, cobalt, molybdenum, chromium, boron, magnesium, iron, copper, calcium, zinc, and selenium were determined in the kidney tissue samples by ICP-AES. Higher molybdenum, calcium, zinc, and selenium values were found in both swimming and nonswimming diabetic rats. Significantly higher iron values were found in swimming, diabetic, diabetic swimming, and zinc-supplemented diabetic swimming rats (p < 0.001). Diabetic, zinc-supplemented diabetic, diabetic swimming, and zinc-supplemented diabetic swimming rats had the highest copper values. These results show that zinc supplementation normalized the higher levels of molybdenum, calcium, selenium, and iron levels seen in diabetic rats, indicating that zinc may have a regulatory effect on element metabolism in kidney tissue.