Accelerated wound healing and anti-inflammatory effects of physically cross linked polyvinyl alcohol–chitosan hydrogel containing honey bee venom in diabetic rats

Diabetes is one of the leading causes of impaired wound healing. The objective of this study was to develop a bee venom-loaded wound dressing with an enhanced healing and anti-inflammatory effects to be examined in diabetic rats. Different preparations of polyvinyl alcohol (PVA), chitosan (Chit) hydrogel matrix-based wound dressing containing bee venom (BV) were developed using freeze–thawing method. The mechanical properties such as gel fraction, swelling ratio, tensile strength, percentage of elongation and surface pH were determined. The pharmacological activities including wound healing and anti-inflammatory effects in addition to primary skin irritation and microbial penetration tests were evaluated. Moreover, hydroxyproline, glutathione and IL-6 levels were measured in the wound tissues of diabetic rats. The bee venom-loaded wound dressing composed of 10 % PVA, 0.6 % Chit and 4 % BV was more swellable, flexible and elastic than other formulations. Pharmacologically, the bee venom-loaded wound dressing that has the same pervious composition showed accelerated healing of wounds made in diabetic rats compared to the control. Moreover, this bee venom-loaded wound dressing exhibited anti-inflammatory effect that is comparable to that of diclofenac gel, the standard anti-inflammatory drug. Simultaneously, wound tissues covered with this preparation displayed higher hydroxyproline and glutathione levels and lower IL-6 levels compared to control. Thus, the bee venom-loaded hydrogel composed of 10 % PVA, 0.6 % Chit and 4 % BV is a promising wound dressing with excellent forming and enhanced wound healing as well as anti-inflammatory activities.     

Influence of tetrahydrocurcumin on hepatic and renal functional markers and protein levels in experimental type 2 diabetic rats

Curcumin is the most active component of turmeric. It is believed that curcumin is a potent antioxidant and anti-inflammatory agent. Tetrahydrocurcumin is one of the major metabolites of curcumin that exhibits many of the same physiologic and pharmacological activities as curcumin and in some systems may exert greater antioxidant activity than curcumin. Oral administration of tetrahydrocurcumin at 80 mg/kg body weight to diabetic rats for 45 days resulted in a significant reduction in blood glucose and significant increase in plasma insulin levels. In addition, the diabetic rats had decreased levels of plasma total protein, albumin, globulin and albumin/globulin ratio as compared to control rats. After treatment with tetrahydrocurcumin and curcumin total protein, albumin, globulin and albumin/globulin ratio were brought back to near normal. The activities of hepatic and renal markers were significantly elevated in diabetic rats as compared to control rats, and treatment with tetrahydrocurcumin and curcumin has reversed these parameters to near normal levels. In diabetic rats, the decreased levels of urea, uric acid and creatinine with increased levels of albumin and urine volume was observed, and treatment with tetrahydrocurcumin and curcumin reversed these parameters to near normal. Tetrahydrocurcumin appeared to have a better protective effect when compared to curcumin.     

Accelerated healing of excisional skin wounds by PL 14736 in alloxan-hyperglycemic rats

PL 14736 is a synthetic peptide, originally isolated from human gastric juice, that has anti-inflammatory and tissue-protective actions in experimental models of gastrointestinal inflammation. To investigate its possible benefit in poorly healing skin wounds, the effects of the topical application of PL 14736 in a gel formulation have been studied on full-thickness excisional wounds in rats, either healthy or made hyperglycemic by alloxan (175 mg/kg s.c.) 5 days previously. The effects of becaplermin gel (platelet-derived growth factor, PDGF-BB, Regranex, a standard therapy for diabetic foot ulcers, were investigated for comparison. Healing was evaluated for up to 7 days after wounding, using digital planimetry analysis, macroscopic scoring and histology. While healing was too rapid in healthy rats to observe enhancement by either treatment, in the hyperglycemic rats which exhibited delayed healing, PL 14736 (10-1,000 microg/wound) produced a dose-dependent acceleration of wound healing (determined by macroscopic scoring) equivalent at the highest doses to that observed with becaplermin. The beneficial effect on healing was associated with increased deposition of organized granulation tissue by day 7 for both PL 14736 and becaplermin, as determined histologically. PL 14736 tended to have a greater effect than becaplermin on the formation of granulation tissue containing mature collagen. Wound contraction, as measured by planimetry, was not significantly affected. In conclusion, topical PL 14736 produces a dose-dependent acceleration of deficient skin wound healing in hyperglycemic rats by facilitating granulation tissue formation, similar to the response seen with topical becaplermin, the standard therapy for diabetic skin wounds. PL 14736 may represent an alternative therapy for delayed wound healing, such as that seen with diabetic foot ulcers, without the proliferative concerns or immunogenicity associated with growth factors.     

The effects of gold nanoparticles in wound healing with antioxidant epigallocatechin gallate and α-lipoic acid

Topical applications of antioxidant agents in cutaneous wounds have attracted much attention. Gold nanoparticles (AuNPs), epigallocatechin gallate (EGCG), and α-lipoic acid (ALA) were shown to have antioxidative effects and could be helpful in wound healing. Their effects in Hs68 and HaCaT cell proliferation and in mouse cutaneous wound healing were studied. Both the mixture of EGCG + ALA (EA) and AuNPs + EGCG + ALA (AuEA) significantly increased Hs68 and HaCaT proliferation and migration. Topical AuEA application accelerated wound healing on mouse skin. Immunoblotting of wound tissue showed significant increase of vascular endothelial cell growth factor and angiopoietin-1 protein expression, but no change of angiopoietin-2 or CD31 after 7 days. After AuEA treatment, CD68 protein expression decreased and Cu/Zn superoxide dismutase increased significantly in the wound area. In conclusion, AuEA significantly accelerated mouse cutaneous wound healing through anti-inflammatory and antioxidation effects. This study may support future studies using other antioxidant agents in the treatment of cutaneous wounds. FROM THE CLINICAL EDITOR: In this study, topically applied gold nanoparticles with epigallocatechin gallate and alpha-lipoic acid were studied regarding their effects in wound healing in cell cultures. Significant acceleration was demonstrated in wound healing in a murine model.     

The effect of curcumin on glutathione-linked enzymes in K562 human leukemia cells.

Curcumin, an antioxidant present in the spice turmeric (Curcuma longa), has been shown to inhibit chemical carcinogenesis in animal models and has been shown to be an anti-inflammatory agent. While mechanisms of its biological activities are not understood, previous studies have shown that it modulates glutathione (GSH)-linked detoxification mechanisms in rats. In the present studies, we have examined the effects of curcumin on GSH-linked enzymes in K562 human leukemia cells. One micromolar curcumin in medium (16 h) did not cause any noticeable change in glutathione peroxidase (GPx), glutathione reductase, and glucose-6-phosphate dehydrogenase activities. Gamma-glutamyl-cysteinyl synthetase activity was induced 1.6-fold accompanied by a 1.2-fold increase in GSH levels. GSH S-transferase (GST) activities towards 1-chloro-2,4-dinitrobenzene, and 4-hydroxynonenal (4HNE) were increased in curcumin-treated cells 1.3- and 1.6-fold, respectively (P = 0.05). The GST isozyme composition of K562 cells was determined as follows: 66% of GST Pl-1, 31% of Mu class GST(s), and 3% of an anionic Alpha-class isozyme hGST 5.8, which was immunologically similar to mouse GSTA4-4 and displayed substrate preference for 4HNE. The isozyme hGST 5.8 appeared to be preferentially induced by curcumin, as indicated by a relatively greater increase in activity toward 4HNE. Immunoprecipitation showed that GPx activity expressed by GST 5.8 contributed significantly (approximately 50%) to the total cytosolic GPx activity of K562 cells to lipid hydroperoxides. Taken together, these results suggest that GSTs play a major role in detoxification of lipid peroxidation products in K562 cells, and that these enzymes are modulated by curcumin.     

Enhanced healing efficacy of an optimized gabapentin-melittin nanoconjugate gel-loaded formulation in excised wounds of diabetic rats

The present study aimed to design and optimize, a nanoconjugate of gabapentin (GPN)-melittin (MLT) and to evaluate its healing activity in rat diabetic wounds. To explore the wound healing potency of GPN-MLT nanoconjugate, an in vivo study was carried out. Diabetic rats were subjected to excision wounds and received daily topical treatment with conventional formulations of GPN, MLT, GPN-MLT nanoconjugate and a marketed formula. The outcome of the in vivo study showed an expedited wound contraction in GPN-MLT-treated animals. This was confirmed histologically. The nanoconjugate formula exhibited antioxidant activities as evidenced by preventing malondialdehyde (MDA) accumulation and superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic exhaustion. Further, the nanoconjugate showed superior anti-inflammatory activity as it inhibited the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). This is in addition to enhancement of proliferation as indicated by increased expression of transforming growth factor-β (TGF- β), vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor receptor-β (PDGFRB). Also, nanoconjugate enhanced hydroxyproline concentration and mRNA expression of collagen type 1 alpha 1 (Col 1A1). In conclusion, a GPN-MLT nanoconjugate was optimized with respect to particle size. Analysis of pharmacokinetic attributes showed the mean particle size of optimized nanoconjugate as 156.9 nm. The nanoconjugate exhibited potent wound healing activities in diabetic rats. This, at least partly, involve enhanced antioxidant, anti-inflammatory, proliferative and pro-collagen activities. This may help to develop novel formulae that could accelerate wound healing in diabetes.     

Enhancement of wound healing by shikonin analogue 93/637 in normal and impaired healing

Wound healing is a complicated biological process, which involves interactions of multiple cell types, various growth factors, their mediators and the extracellular matrix proteins. In this study, we evaluated the effects of shikonin analogue 93/637 (SA), derived from the plant Arnebia nobilis, on normal and hydrocortisone-induced impaired healing in full thickness cutaneous punch wounds in rats. SA (0.1%) was applied topically daily as an ointment in polyethylene glycol base on wounds. SA treatment significantly accelerated healing of wounds, as measured by wound contraction compared to controls in hydrocortisone-impaired animals. SA treatment promoted formation of granulation tissue including cell migration and neovascularization, collagenization and reepithelialization. The expression of basic fibroblast growth factor (bFGF) was higher as revealed by immunohistochemistry in treated wounds compared to controls. However, the expression of transforming growth factor-beta(1) was not affected by SA treatment. Since bFGF is known to accelerate wound healing, the increased expression of bFGF by SA may be partly responsible for the enhancement of wound healing. These studies suggest that SA could be further studied for clinical use to enhance wound healing.     

Curcumin attenuates dimethylnitrosamine-induced liver injury in rats through Nrf2-mediated induction of heme oxygenase-1.

Curcumin (diferuloymethane), a yellow colouring agent present in the rhizome of Curcuma longa Linn (Zingiberaceae), has been reported to possess anti-inflammatory, antioxidant, antimutagenic and anticarcinogenic activities. Curcumin exerts its chemoprotective and chemopreventive effects via multiple mechanisms. It has been reported to induce expression of the antioxidant enzymes in various cell lines. Heme oxygenase-1 (HO-1) is an important antioxidant enzyme that plays a pivotal role in cytoprotection against noxious stimuli of both endogenous and exogenous origin. In the present study, we found that oral administration of curcumin at 200mg/kg dose for four consecutive days not only protected against dimethylnitrosamine (DMN)-induced hepatic injury, but also resulted in more than three-fold induction of HO-1 protein expression as well as activity in rat liver. Inhibition of HO-1 activity by zinc protoporphyrin-IX abrogated the hepatoprotective effect of curcumin against DMN toxicity. NF-E2-related factor 2 (Nrf2) plays a role in the cellular protection against oxidative stress through antioxidant response element (ARE)-directed induction of several phase-2 detoxifying and antioxidant enzymes including HO-1. Curcumin administration resulted in enhanced nuclear translocation and ARE-binding of Nrf2. Taken together, these findings suggest that curcumin protects against DMN-induced hepatotoxicity, at least in part, through ARE-driven induction of HO-1 expression.     

In vivo systemic chlorogenic acid therapy under diabetic conditions: Wound healing effects and cytotoxicity/genotoxicity profile

Oxidative stress occurs following the impairment of pro-oxidant/antioxidant balance in chronic wounds and leads to harmful delays in healing progress. A fine balance between oxidative stress and endogenous antioxidant defense system may be beneficial for wound healing under redox control. This study tested the hypothesis that oxidative stress in wound area can be controlled with systemic antioxidant therapy and therefore wound healing can be accelerated. We used chlorogenic acid (CGA), a dietary antioxidant, in experimental diabetic wounds that are characterized by delayed healing. Additionally, we aimed to understand possible side effects of CGA on pivotal organs and bone marrow during therapy. Wounds were created on backs of streptozotocin-induced diabetic rats. CGA (50 mg/kg/day) was injected intraperitoneally. Animals were sacrificed on different days. Biochemical and histopathological examinations were performed. Side effects of chronic antioxidant treatment were tested. CGA accelerated wound healing, enhanced hydroxyproline content, decreased malondialdehyde/nitric oxide levels, elevated reduced-glutathione, and did not affect superoxide dismutase/catalase levels in wound bed. While CGA induced side effects such as cyto/genotoxicity, 15 days of treatment attenuated blood glucose levels. CGA decreased lipid peroxidation levels of main organs. This study provides a better understanding for antioxidant intake on diabetic wound repair and possible pro-oxidative effects.     

Topical oxygen therapy induces vascular endothelial growth factor expression and improves closure of clinically presented chronic wounds

1. Chronic wounds, especially in diabetics, represent a serious threat to human health. 2. Correcting a compromised state of tissue oxygenation by the administration of supplemental O(2) is known to benefit wound healing. Beyond its role as a nutrient and antibiotic, O(2) supports wound healing by driving redox signaling. 3. Hyperbaric oxygen (HBO) therapy is widely used and approved by Center for Medicare and Medicaid Services to treat specific ulcerations. The current literature supports the notion that approaches to topically oxygenate wounds may be productive. 4. Here, we present the results of two simultaneous studies testing the effects of HBO and portable topical oxygen (TO) therapies. These two therapeutic approaches have several contrasting features. 5. In total, 1854 patients were screened in outpatient wound clinics for non-randomized enrolments into the HBO (n = 32; 31% diabetic) and TO (n = 25; 52% diabetic) studies. 6. Under the conditions of the present study, HBO treatment seemed to benefit some wounds while not benefiting others. Overall, HBO did not result in statistically significant improvements in wound size in the given population over the time monitored in the present study. 7. However, TO significantly improved wound size. Among the three O(2)-sensitive genes (VEGF, TGFbeta1 and COL1A1) studied in wound edge tissue biopsies, TO treatment was associated with higher VEGF165 expression in healing wounds. Expression of the other genes mentioned was not affected by TO. There was no significant change in the expression levels of any of genes studied in patients in the HBO study. This establishes a link between VEGF gene expression and healing outcome for TO therapy. 8. Taken together, the present study provides evidence demonstrating that TO treatment benefits wound healing in patients suffering from chronic wounds. Treatment with TO is associated with an induction of VEGF expression in wound edge tissue and an improvement in wound size.     

Potential activity of aqueous extract of culinary-medicinal Lion's Mane mushroom, Hericium erinaceus (Bull.: Fr.) Pers. (Aphyllophoromycetideae) in accelerating wound healing in rats

This study was conducted to evaluate the effects of topical application of aqueous extract of Hericium erinaceus fruiting bodies (HEFB) on the rate of wound healing enclosure and histology of the healed wound. Five groups of male Sprague-Dawley rats were experimentally wounded in the posterior neck area. A uniform wound area of 2.00 cm in diameter, using a circular stamp, was excised from the nape of the dorsal neck of all rats with the aid of a round seal. The animal groups were topically treated, respectively, with 0.2 mL each of sterilized distilled water (sdH2O); Intrasite gel; and 20, 30, and 40 mg/mL HEFB. Macroscopically, those rats whose wounds were dressed with HEFB and those in the Intrasite gel-treated group healed earlier than those treated with sdH2O. Histological analysis of healed wounds dressed with HEFB showed less scar width at wound enclosure and the healed wound contained fewer macrophages and more collagen with angiogenesis, compared to wounds dressed with sdH2O. In conclusion, wounds dressed with HEFB significantly enhanced the acceleration of wound healing enclosure in rats.     

Liposomal delivery system enhances anti-inflammatory properties of curcumin

Curcumin is a well-established natural antioxidant and anti-inflammatory agent. Up till now its potential in treatment of vaginal inflammation has not been evaluated. We are aiming at developing liposomal delivery system for curcumin targeting vaginal administration. Liposomes as nanosized phospholipid-based vesicles are expected to solubilize curcumin and enhance its activity, thus serving as an advanced topical formulation in the treatment of vaginal inflammation. Curcumin and curcuminoids were analyzed by the high-performance liquid chromatography method. Liposomes containing curcumin/curcuminoids of various sizes were prepared and characterized. Antioxidant activities of curcumin and liposomal curcumin were compared based on 1,1-diphenyl-2-picrylhydrazyl radical scavenging and superoxide dismutase activities. The anti-inflammatory activities were determined by measuring the inhibition of lipopolysaccharide -induced nitric oxide, interleukin-1β, and tumor necrosis factor-α production in macrophage RAW 264.7 cells. Curcumin/curcuminoids were encapsulated in phosphatidylcholine vesicles with high yields. Vesicles in the size range around 200 nm were selected for stability and cell experiments. Liposomal curcumin were found to be twofold to sixfold more potent than corresponding curcuminoids. Moreover, the mixture of curcuminoids was found to be more potent than pure curcumin in regard to the antioxidant and anti-inflammatory activities. Liposomal delivery systems for curcumin are promising formulations for the treatment of vaginal inflammation.     

Curcumin activates human glutathione S-transferase P1 expression through antioxidant response element

Curcumin is a plant-derived diferuloylmethane compound extracted from Curcuma longa, possessing antioxidative and anticarcinogenic properties. Antioxidants and oxidative stress are known to induce the expression of certain classes of detoxification enzymes. Since the upregulation of detoxifying enzymes affects the drug metabolism and cell defense system, it is important to understand the gene regulation by such agents. In this study, we demonstrated that curcumin could induce the expression of human glutathione S-transferase P1 (GSTP1). In HepG2 cells treated with 20 μM curcumin, the level of GSTP1 mRNA was significantly increased. In luciferase reporter assays, curcumin augmented the promoter activity of a reporter construct carrying 336 bp upstream of the 5′-flanking region of the GSTP1 gene. Mutation analyses revealed that the region including antioxidant response element (ARE), which overlaps AP1 in sequence, was essential to the response to curcumin. While the introduction of a wild-type Nrf2 expression construct augmented the promoter activity of the GSTP1 gene, co-expression of a dominant-negative Nrf2 abolished the responsiveness to curcumin. In addition, curcumin activated the expression of the luciferase gene from a reporter construct carrying multiple ARE consensus sequences but not one with multiple AP1 sites. In a gel mobility shift assay with an oligonucleotide with GSTP1 ARE, an increase in the amount of the binding complex was observed in the nuclear extracts of curcumin-treated HepG2 cells. These results suggested that ARE is the primary sequence for the curcumin-induced transactivation of the GSTP1 gene. The induction of GSTP1 may be one of the mechanisms underlying the multiple actions of curcumin.     

Asiaticoside nitric oxide gel accelerates diabetic cutaneous ulcers healing by activating Wnt/β-catenin signaling pathway

Diabetic ulcers, gangrene, local infections and other traumatic symptoms of wound healing are all directly related. Promoting the early healing of diabetic cutaneous ulcers (DCU) and reducing the disability and treatment costs is an important research project integrating traditional Chinese and Western medicine. Nitric oxide (NO) is a key component of wound healing, and endogenous NO secretion is insufficient during the development of DCU. It has been reported that exogenous NO can promote wound healing, but exogenous NO has a short half-life and is difficult to adhere to the skin. Asiaticoside (AC) is extracted from the traditional Chinese medicine Centella asiatica, and has angiogenic, anticancer, antioxidant, anti-inflammatory, and wound-healing effects. Therefore, our study is based on the hypothesis that the combination of AC and NO to treat DCU is possible. In this study we considered gels of AC and NO, and evaluated the effects of the gel on DCU healing. Based on our study, it was found that the combined effect of asiaticoside and NO could accelerate the healing rate of DCU wounds. The asiaticoside NO gel can inhibit the growth of bacteria in the wound surface, alleviate the inflammatory reaction of wound, and increase the expression of VEGF, iNOS, eNOS and CD34. Our research shows that asiaticoside NO gel may promote DCU wound healing by regulating Wnt/β-Catenin signaling pathway. It will provide new targets and strategies for the diagnosis and treatment of DCU.     

Ethanol extract of Cotinus coggygria leaves accelerates wound healing process in diabetic rats

Context: Cotinus coggygria Scop. (Anacardiaceae) leaves that were used as wound healing in traditional Balkan and Anatolian folk medicine, could be potentially effective in treating diabetic wounds.

Objective: This study investigates biochemical and histological effects of ethanol extract of C. coggygria (CCE) on excision wound model in diabetic rats.

Materials and methods: This study was conducted on diabetic Wistar albino rats, which were injected by a single dose (50?mg/kg i.p.) streptozotocin. Afterward an excision wound model was created in all animals; diabetic control rats were applied topically simple ointment and diabetic treatment rats were applied topically 5% (w/w) ointment with CC, once a day during the experimental period. Malondialdehyde, glutathione and hydroxyproline levels in wound tissues were investigated at the end of 3rd, 7th, and 14th days. Histopathological examination was also performed.

Results: Hydroxyproline content was significantly increased in the CCE treated group versus control after the 3rd and 7th days (15.33 versus 11.83; 19.67 versus 15.67?mg/g, p?<?0.05; respectively). A statistically significant elevation in glutathione at the end of 3rd, 7th, and 14th days (5.13 versus 1.58, p?<?0.05; 4.72 versus 1.88, p?<?0.05; 3.83 versus 1.88?μmol/g, p?<?0.05, respectively) and a statistically significant decrease in malondialdehyde level at the end of 7th day (4.49 versus 1.48?nmol/g, p?<?0.05) were determined in the treated group versus control group. These results were also supported by histological analyses.

Discussion and conclusion: These findings indicate that CCE accelerated the cutaneous wound healing process in diabetic wounds, in confirmation of its traditional use.     

Curcumin inhibition of bleomycin-induced pulmonary fibrosis in rats

Curcumin, an anti-inflammatory, antioxidant, was evaluated for its ability to suppress bleomycin (BLM)-induced pulmonary fibrosis in rats. A single intratracheal instillation of BLM (0.75 U 100(-1) g, sacrificed 3, 5, 7, 14 and 28 days post-BLM) resulted in significant increases in total cell numbers, total protein, and angiotensin-converting enzyme (ACE), and alkaline phosphatase (AKP) activities in bronchoalveolar lavage fluid. Animals with fibrosis had a significant increase in lung hydroxyproline content. Alveolar macrophages from BLM-administered rats elaborated significant increases in tumour necrosis factor (TNF)-alpha release, and superoxide and nitric oxide production in culture medium. Interestingly, oral administration of curcumin (300 mg kg(-1) 10 days before and daily thereafter throughout the experimental time period) inhibited BLM-induced increases in total cell counts and biomarkers of inflammatory responses in BALF. In addition, curcumin significantly reduced the total lung hydroxyproline in BLM rats. Furthermore, curcumin remarkably suppressed the BLM-induced alveolar macrophage production of TNF-alpha, superoxide and nitric oxide. These findings suggest curcumin as a potent anti-inflammatory and anti-fibrotic agent against BLM-induced pulmonary fibrosis in rats.     

Curcumin decreases oxidative stress in mitochondria isolated from liver and kidneys of high-fat diet-induced obese mice

Oxidative stress plays a key role in obesity and diabetes-related mitochondrial dysfunction. Mitochondrial dysfunction is characterized by increased oxidative damage, nitric oxide (NO) synthesis, and a reduced ratio of adenosine-5'-triphosphate (ATP) production/oxygen consumption. Curcumin represents a potential antioxidant and anti-inflammatory agent. In this study, our objective was to determine the effect of curcumin treatment on oxidative stress and mitochondrial dysfunction in high-fat diet (HFD)-induced obese mice (OM). These results suggest that curcumin treatment increased oxygen consumption and significantly decreased lipid and protein oxidation levels in liver mitochondria isolated from HFD-induced OM compared with those in the untreated OM (UOM). In kidney mitochondria, curcumin treatment significantly increased oxygen consumption and decreased lipid and protein peroxidation levels in HFD-induced OM when compared with those in UOM. Curcumin treatment neither has any effect on body weight gain nor have any effects on mitochondrial NO synthesis. These findings suggest that obesity induces oxidative stress and mitochondrial dysfunction, whereas curcumin may have a protective role against obesity-induced oxidative stress and mitochondrial dysfunction.     

Curcumin and neurodegenerative diseases: a perspective

INTRODUCTION: Curcumin, a dietary polyphenol found in the curry spice turmeric, possesses potent antioxidant and anti-inflammatory properties and an ability to modulate multiple targets implicated in the pathogenesis of chronic illness. Curcumin has shown therapeutic potential for neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). AREAS COVERED: This article highlights the background and epidemiological evidence of curcumin's health benefits and its pharmacodynamic and pharmacokinetic profile. Curcumin's ability to counteract oxidative stress and inflammation and its capacity to modulate several molecular targets is reviewed. We highlight the neuroprotective properties of curcumin including pre-clinical evidence for its pharmacological effects in experimental models of AD and PD. The bioavailability and safety of curcumin, the development of semi-synthetic curcuminoids as well as novel formulations of curcumin are addressed. EXPERT OPINION: Curcumin possesses therapeutic potential in the amelioration of a host of neurodegenerative ailments as evidenced by its antioxidant, anti-inflammatory and anti-protein aggregation effects. However, issues such as limited bioavailability and a paucity of clinical studies examining its therapeutic effectiveness in illnesses such as AD and PD currently limit its therapeutic outreach. Considerable effort will be required to adapt curcumin as a neuroprotective agent to be used in the treatment of AD, PD and other neurodegenerative diseases.     

ROCK1 inhibitor fasudil improves diabetic wound healing via AMPK/Drp1/eNOS pathway

OBJECTIVE Refractory wounds in diabetic patients constitute a serious complication that often leads to amputation and has limited treatment regimens.As the first approved Rho-associated protein kinase 1(ROCK1) inhibitor, fasudil has positive effects on cardiovascular system. The present study was designed to determine the protective effect of fasudilon diabetic wound healing and investigate underlying mechanisms.METHODS In vivo, streptozotocin(STZ)-induced type 1 diabetic mice with full-thickness excisional wounds were intraperitoneally administered with 1, 3 or 10 mg·kg~(-1)·d~(-1) of fasudil. Wound closure, blood perfusion(doppler flow imaging), histomorphology(hematoxylin and eosin stain),angiogenesis(immunochemistry of CD31), reactive oxygen species(ROS)(Mito Sox and DHE) and NO production(Nitrite) were detected. In vitro, human umbilical vein endothelial cells(HUVECs) were exposed to high concen-trations of glucose(HG), treated with fasudil or si RNA of ROCK1. Endothelial function(tube formation assay),ROS(Mito Sox and DHE, Flow cytometry) were detected in HUVECs. The expression of key proteins was detected by Western blotting and quantitative real time polymerase chain reaction(q PCR). Histomorphology and key protein production of diabetics were also detected.RESULTS The protein levels of ROCK1 were increased both in diabetics, diabetic mice, and HUVECs. Fasudil dose-dependently rescued the delay of wound closure and increased the mean perfusion rate around the wound in diabetic mice. Diabetic conditions markedly increased mitochondrial oxygen superoxide anion(O_2·-)production and nitrotyrosine formation, decreased NO production and angiogenesis in wound tissues, which were normalized with 10 mg · kg~(-1) fasudil treatment. In HUVECs, treatment with fasudil and si RNA of ROCK1 significantly attenuated ROS production, increased expression of angiogenesis-associated genes and improved endothelial function under HG. Fasudil increased the ratio of p-AMPK/AMPK and p-e NOS/e NOS, decreased the expression and phosphorylation of Drp1 under HG in vivo and in vitro. Administration of compound C inverted the in vitro effects of fasudil or si RNA of ROCK1. CONCLUSION Fasudil rescued the delayed wound healing and improved wound angiogenesis in STZ-induced type 1 diabetic mice, at least in part, via AMPK/Drp1/e NOS pathway.     

Curcumin attenuates gentamicin-induced renal oxidative damage in rats.

The present investigation reports the effect of curcumin, an antioxidant, on gentamicin-induced-renal oxidative damage in rats. Curcumin (200 mg/kg p.o.) was administered for 2 weeks before and 1 week simultaneously with gentamicin (100 mg/kg i.p.). Saline treated rats served as control. Serum creatinine, blood urea (BUN), urinary protein, glucose, urine gamma glutamyl transferase and urine volume increased in rats treated with gentamicin while creatinine clearance decreased compared to controls P<0.001. Renal histological examination revealed tubular necrosis. Curcumin significantly normalized the above parameters. Gentamicin decreased the activities of catalase (CAT), gutathione peroxidase (GSHPx) and the level of glutathione (GSH) but the activity of copper, zinc-superoxide dismutase (Cu, Zn-SOD) was unaltered compared to control. Curcumin attenuated the gentamicin-induced reduction in the activities of CAT, GSHPx and level of GSH by 31%, 55% and 74%, respectively. Curcumin attenuated the gentamicin-induced increases in both plasma malondialdehyde (MDA) and kidney MDA by 57% and 62%, respectively, as well as lipid hydroperoxide (LOOH) formation by 52% and 56% in rat plasma and kidney, respectively. However, Curcumin did not reduce gentamicin-induced formation of LOOH, both in the plasma and kidney, in the presence of exogenous oxidants (1 mM FeSO4, 1 mM ascorbate, 0.2 mM H2O2). Our data indicate that the natural antioxidant curcumin can be a potent protective agent against renal oxidative damage mediated by gentamicin.