Anti-inflammatory and anti-allergic effects of Cheonwangbosim-dan water extract: An in vitro and in vivo study

Ethnopharmacological relevance

Cheonwangbosim-dan is a traditional herbal prescription that is widely used to improve or treat physical and mental illnesses in East Asian countries.Aim of the study: The aim of the present study was to investigate the preventive and protective effects of a Cheonwangbosim-dan water extract (CBDW) against allergic inflammation using in vitro and in vivo models.

Materials and methods

BEAS-2B and MC/9 cells were treated with various concentrations of CBDW and stimulated with different inducers of inflammatory mediators. The production of various inflammatory mediators was subsequently evaluated. BALB/c mice were sensitized and challenged by repeated application of ovalbumin (OVA). CBDW was administered by oral gavage once daily for 10 consecutive days. We assessed the number of inflammatory cells and production of Th2 cytokines in bronchoalveolar lavage fluid (BALF), the plasma levels of total and OVA-specific immunoglobulin E (IgE), and histological changes in lung tissue.

Results

Our findings showed that CBDW significantly decreased the levels of various inflammatory mediators (eotaxin-1, eotaxin-3, RANTES, LTC₄, TNF-α, MMP-9, 5-LO, ICAM-1, and VCAM-1) in vitro, significantly reduced the accumulation of total inflammatory cells, the production of Th2 cytokines (IL-5 and IL-13), the levels of IgE (total and OVA-specific) in vivo, and remarkably inhibited histological changes (infiltration of inflammatory cells and goblet cell hyperplasia) in vivo.

Conclusions

These results suggest that CBDW possesses anti-inflammatory and anti-allergic properties by lowering allergic inflammation.

Ethanol Extract of Elaeagnus glabra f. oxyphylla Branches Alleviates the Inflammatory Response Through Suppression of Cyclin D3/Cyclin-Dependent Kinase 11p58 Coupled to Lipopolysaccharide-Activated BV-2 Microglia

Neuroinflammation plays a pivotal role in the pathogenesis of neurodegenerative diseases and is characterized by microglial dysregulation. Here, we explored the beneficial effects of a leaf extract of Elaeagnus glabra f. oxyphylla (EGFO), a native medicinal plant to Korea, South China, Japan, and Taiwan, on neuroinflammation using lipopolysaccharide (LPS)-stimulated BV-2 microglia. Levels of the inflammatory mediators were determined by enzyme-linked immunosorbent assays and reverse transcription–polymerase chain reaction. The phospho levels of mitogen-activated protein kinases, which are key kinase molecules in the inflammatory signaling pathway in microglia, were analyzed by Western blotting. Treatment with EGFO significantly suppressed the LPS-mediated induction of nitric oxide and prostaglandin E2. Consistently, EGFO treatment in LPS-stimulated BV-2 cells markedly reduced the inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels. The best concentration of EGFO that could reduce TNF-α and IL-6 was 100 μg/mL. EGFO relatively reduced the messenger RNA expression of TNF-α and IL-6 by 0.36 and 0.32-fold ratio, respectively, compared to LPS treatment. Moreover, EGFO markedly reduced the phospho levels of p38 and the c-jun N-terminal kinase. Furthermore, antibody microarray and immunoblotting data revealed that the pharmacological mechanisms driving the antineuroinflammatory action of EGFO involve prevention of the cyclin D3/cyclin-dependent kinase 11p58 (CDK11p58) interaction. In conclusion, our results demonstrate that EGFO alleviates the inflammatory response through the suppression of cyclin D3/CDK11p58 coupling in LPS-activated BV-2 microglia. We propose the potential of EGFO as a novel drug candidate for neurodegenerative diseases by targeting neuroinflammation.

Ficus erecta Thunb. Leaves Ameliorate Cognitive Deficit and Neuronal Damage in a Mouse Model of Amyloid-β-Induced Alzheimer's Disease

Alzheimer's disease (AD) pathogenesis is linked to amyloid plaque accumulation, neuronal loss, and brain inflammation. Ficus erecta Thunb. is a food and medicinal plant used to treat inflammatory diseases. Here, we investigated the neuroprotective effects of F. erecta Thunb. against cognitive deficit and neuronal damage in a mouse model of amyloid-β (Aβ)-induced AD. First, we confirmed the inhibitory effects of ethanol extracts of F. erecta (EEFE) leaves on Aβ aggregation in vivo and in vitro. Next, behavioral tests (passive avoidance task and Morris water maze test) revealed EEFE markedly improved cognitive impairment in Aβ-injected mice. Furthermore, EEFE reduced neuronal loss and the expression of neuronal nuclei (NeuN), a neuronal marker, in brain tissues of Aβ-injected mice. EEFE significantly reversed Aβ-induced suppression of cAMP response element-binding protein (CREB) phosphorylation and brain-derived neurotrophic factor (BDNF) expression, indicating neuroprotection was mediated by the CREB/BDNF signaling. Moreover, EEFE significantly suppressed the inflammatory cytokines interleukin 1beta (IL-1β) and tumor necrosis factor alpha (TNF-α), and expression of ionized calcium-binding adaptor molecule 1 (Iba-1), a marker of microglial activation, in brain tissues of Aβ-injected mice, suggesting anti-neuroinflammatory effects. Taken together, EEFE protects against cognitive deficit and neuronal damage in AD-like mice via activation of the CREB/BDNF signaling and upregulation of the inflammatory cytokines.

Simultaneous Quantification of Four Marker Compounds in Bauhinia coccinea Extract and Their Potential Inhibitory Effects on Alzheimer's Disease Biomarkers

Bauhinia coccinea is a tropical woody plant widely distributed in Vietnam and Unnan in southern China. Although many studies have shown the biological activities of extracts from various other species in the genus, no studies have investigated the effects of B. coccinea extracts on biological systems. In the present study, a quantitative analysis of four marker compounds of ethanol extracts of B. coccinea branches (EEBC) was performed using the high performance liquid chromatography (HPLC)-photodiode array (PDA) method. Among gallic acid, (+)-catechin, ellagic acid, and quercitrin contained in EEBC, the most abundant compound was (+)-catechin (18.736 mg/g). In addition, we investigated the EEBC on neuroprotection, antioxidation, and Alzheimer’s disease (AD) marker molecules, acetylcholinesterase (AChE), and amyloid-β (Aβ). EEBC significantly inhibited hydrogen peroxide (H₂O₂)-induced cell death in a HT22 neuronal cell line and increased 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl scavenging activity markedly. EEBC also inhibited AChE and Aβ aggregation. Among the four compounds, gallic acid exhibited strong inhibitory effects against AChE activation. In the Aβ aggregation assay, the four marker compounds exhibited inhibitory effects lower than 30%. According to the results, EEBC could exert anti-AChE activation and Aβ aggregation activities based on the interactive effects of the marker compounds. Our findings suggest that EEBC are sources of therapeutic candidates for application in the development of AD medication based on AChE and Aβ dual targeting.

Ficus erecta Thunb Leaves Alleviate Memory Loss Induced by Scopolamine in Mice via Regulation of Oxidative Stress and Cholinergic System

We examined the neuropharmacological effects of ethanol extract of Ficus erecta Thunb leaves (EEFE) on cognitive dysfunction in a scopolamine (SCO)-induced memory impairment animal model. Memory impairment was measured using the Y-maze test and passive avoidance task (PAT). For 19 days, EEFE (100 or 200 mg/kg) was treated through oral administration. Treatment with EEFE ameliorated memory impairment in behavioral tests, along with significant protection from neuronal oxidative stress and neuronal cell loss in the brain tissues of SCO-injected mice. Antioxidant and neuroprotective effects of EEFE were further confirmed using in vitro assays. Our findings indicate that the mechanisms of neuroprotection and antioxidation of EEFE are regulated by the cholinergic system, promotion of cAMP response element-binding protein (CREB) phosphorylation, and the nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase (HO)-1 signaling activation. The current study proposes that EEFE could be an encouraging plant resource and serve as a potent neuropharmacological drug candidate against neurodegenerative diseases.

Korean traditional herbal formula Soshiho-tang attenuates memory impairment and neuronal damage in mice with amyloid-beta-induced Alzheimer's disease

Background

Soshiho-tang (SST), also known as Xiaochaihu-tang in China and Sho-saiko-to in Japan, is an Oriental herbal formula traditionally used to treat febrile diseases. Recently, several in vitro and in vivo studies have reported the anti-cancer, anti-liver disease, and anti-inflammatory activities of SST. However, there is little evidence of its effects on neurological diseases. We previously reported the inhibitory effects of SST on in vitro acetylcholinesterase (AChE) activation and amyloid-β (Aβ) aggregation, which are crucial hallmarks of Alzheimer's disease (AD). In the present study, we report that SST has preventive effects on memory impairment and neuronal cell changes in an Aβ-induced AD-like mouse model.

Methods

Male mice underwent injection of Aβ aggregates and administered SST (500, 1,000, or 2,000 mg/kg/day) for 20 days. Behavioral tests (passive avoidance task [PAT] and Morris water maze [MWM] test) were conducted. Lastly, brain sections were obtained from sacrificed mice for quantitative analysis.

Results

Intracerebroventricular (ICV) injection of Aβ aggregates significantly decreased the latency time in the PAT and MWM test compared to normal control. In contrast, SST administration markedly reversed the latency caused by Aβ injection. Additionally, our data revealed that SST-mediated improvements in memory impairment are related to its neuroprotective and anti-neuroinflammatory effects. On histological analysis, SST treatment protected neuronal loss and damage as well as microglial activation, and ameliorated amount of Aβ in brain of mouse model of AD.

Conclusion

Our findings suggest that SST may be a promising candidate for the development of novel drugs for AD.

The Effects of Crinum asiaticum var. japonicum Baker Seeds on Neuroprotection and Antineuroinflammation in Neuronal Cell Lines

Crinum asiaticum var. japonicum Baker is a Korean herbal medicine that is traditionally prescribed for reducing fever and inflammation. In the present study, we investigated if the ethanol extract of C. asiaticum seeds (ECAS) influences the hallmarks of Alzheimer’s disease (AD) pathogenesis. ECAS markedly inhibited the activity of acetylcholinesterase (AChE). Concurrent treatment with hydrogen peroxide (H2O2) and ECAS significantly prevented the neuronal cell death by regulating phosphorylation of cyclic adenosine monophosphate response element-binding protein and p38 mitogen-activated protein kinase. ECAS revealed antineuroinflammatory effects by inhibiting nitric oxide production and suppressing inducible nitric oxide expression in lipopolysaccharide-stimulated BV-2 microglia. Furthermore, the high-performance liquid chromatographic analysis determined lycorine as a standard compound of ECAS. Our data suggest that ECAS has inhibitory effects on AD pathogenesis such as AChE activation, neuronal damage, and neuroinflammation.

Annona atemoya leaf extract ameliorates cognitive impairment in amyloid-β injected Alzheimer's disease-like mouse model

Annona atemoya is a hybrid of Annona squamosa and Annona cherimola that grow in several subtropical or tropical areas such as Florida in the US, Philippines, Cuba, Jamaica, Taiwan, and Jeju in South Korea. We report that the A. atemoya leaves (AAL) have inhibitory effects on the pathogenesis and regulatory mechanisms of Alzheimer’s disease (AD). Ethanol extract of AAL prevented amyloid-β (Aβ) aggregation and increased free radical scavenging activity. In addition, AAL extract exerted protective effects against neuronal cell death in HT22 hippocampal cells. Moreover, oral administration of AAL extract significantly improved memory loss in the passive avoidance task and Y-maze test, as well as downregulated the expression of neuronal markers neuronal nuclei and brain-derived neurotrophic factor in Aβ-injected AD mice. To verify the molecular mechanisms responsible for anti-AD actions of AAL, we conducted the antibody microarray analysis and found that epidermal growth factor receptor/G protein-coupled receptor kinase 2 signaling was activated in neuronal cells and AD-like mouse models. Additionally, quantitative analyses of the six standard compounds using high-performance liquid chromatography revealed that rutin is the most abundant compound of AAL. Furthermore, efficacy analyses of six standard compounds showed that rutin and isoquercitrin had significant inhibitory activity on Aβ aggregation. Taken together with biological activity and the content of compounds, rutin maybe a bioactive compound of AAL in the AD pathogenesis. Overall, our findings provide the first scientific support for the therapeutic effects of AAL in AD and AD-related disorders.

Impact statement

Our study was aimed to find a novel candidate drug for Alzheimer’s disease (AD) using natural products. We assessed the effects of Annona atemoya extracts on crucial events in the pathogenesis of AD. A. atemoya leaf (AAL) extract significantly inhibited amyloid-β aggregation, oxidative stress, neuronal cell death, and memory impairment through the epidermal growth factor receptor/G protein-coupled receptor kinase 2 pathway. Simultaneous analysis using HPLC determined six standard compounds of AAL extract, and rutin was identified as a bioactive compound. Of note, the anti-AD activity of AAL extract was more significant compared to other extracts from medicinal plants of which efficacy was previously reported. The potential of AAL extract as an anti-AD agent may provide insight into the new drug development for AD treatment.

Annona atemoya Leaf Extract Improves Scopolamine-Induced Memory Impairment by Preventing Hippocampal Cholinergic Dysfunction and Neuronal Cell Death

We explored the preventative effect of Annona atemoya leaf (AAL) extract on memory impairment in a scopolamine (SCO)-induced cognitive deficit mouse model. Fifty-eight mice were randomly divided into six groups and orally treated with AAL extract at (50, 100, or 200 mg/kg) or tacrine (TAC) for 21 days. Memory deficits were induced by a single injection of 1 mg/kg SCO (i.p.) and memory improvement was evaluated by using behavioral tests such as the passive avoidance task and Y-maze test. The levels of cholinergic functions, neuronal cell death, reactive oxygen species, and protein expression related to hippocampal neurogenesis were examined by immunohistochemical staining and western blotting. The administration of AAL extract improved memory impairment according to increased spontaneous alternation in the Y-maze and step-through latency in passive avoidance test. AAL extract treatment increased the acetylcholine content, choline acetyltransferase, and acetylcholinesterase activity in the hippocampus of SCO-stimulated mice. In addition, AAL extract attenuated oxidative stress-induced neuronal cell death of hippocampal tissue. In terms of the regulatory mechanisms, AAL extract treatment reversed the SCO-induced decreases in the expression of Akt, phosphorylation of cAMP response element binding protein, and brain-derived neurotrophic factor. Our findings demonstrate that AAL extract has the ability to alleviate memory impairment through preventative effect on cholinergic system dysfunction and oxidative stress-related neuronal cell death in a SCO-induced memory deficit animal model. Overall, AAL may be a promising plant resource for the managing memory dysfunction due to neurodegenerative diseases, such as Alzheimer’s disease (AD).

Hwangryunhaedok-Tang Exerts Neuropreventive Effect on Memory Impairment by Reducing Cholinergic System Dysfunction and Inflammatory Response in a Vascular Dementia Rat Model

Hwangryunhaedok-tang (HRT) is a traditional oriental herbal formula used in Asian countries for treating inflammatory diseases and controlling fever. Our present study aimed to determine whether HRT has therapeutic effects for patients with vascular dementia (VaD) using a bilateral common carotid artery occlusion (BCCAO) rat model and assessing spatial memory impairment and activation of neuroinflammation. BCCAO was performed in male Sprague Dawley rats to induce VaD, and oral HRT was administered daily for 30 d. Our data showed that HRT ameliorated BCCAO-induced memory and cognitive impairment in behavioral tests. In addition, HRT reversed cholinergic dysfunction and neuronal damage in the hippocampus of BCCAO rats. Furthermore, HRT attenuated microglial activation and reduced the phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase (JNK) induced by BCCAO. Simultaneous high-performance liquid chromatography analysis of HRT using index compounds from the herbal composition revealed that both HRT ethanol extract and commercial HRT granules primarily comprise geniposide, baicalin, and berberine. Our study showed that HRT administration resulted in the prevention of neuronal injury induced by BCCAO through improvement of cholinergic dysfunction and inhibition of neuroinflammatory responses, suggesting that HRT may have potential as a treatment for VaD.

Bojungikgi-Tang, a Traditional Herbal Formula, Exerts Neuroprotective Effects and Ameliorates Memory Impairments in Alzheimer's Disease-Like Experimental Models

Bojungikgi-tang (BJIGT; Bu Zhong Yi Qi Tang in China, Hochuekkito in Japan) is a traditional Oriental herbal formula comprised of eight medicinal herbs that has long been used for the treatment of digestive disorders. A recent clinical study from South Korea reported that BJIGT-gamibang administration may be effective in treating dementia. We aimed to establish scientific evidence for the anti-dementia effects of BJIGT using in vitro and in vivo experimental models. We measured amyloid- β (Aβ) aggregation, β-secretase (BACE), and antioxidant activity in a cell free system. Neuroprotective effects were assessed using CCK-8. Imprinting control region (ICR) mice were divided into the following six groups: Normal control, Aβ-injected, Aβ-injection + oral BJIGT gavage (200, 400, or 800 mg/kg/day), and Aβ-injection + oral morin administration (10 mg/kg/day). Subsequently, behavioral evaluations were conducted and brain samples were collected from all the animals and assessed. BJIGT enhanced inhibition of Aβ aggregation and BACE activity in vivo, as well as antioxidant activity in in vitro, cell-free systems. BJIGT also exerted neuroprotective effects in a hydroperoxide (H₂O₂)-induced damaged HT22 hippocampal cell line model. In addition, BJIGT administration significantly ameliorated cognitive impairments in Aβ-injected mice, as assessed by the passive avoidance and Y-maze tests. Furthermore, BJIGT treatment suppressed Aβ aggregation and expression, as well as expression of Aβ, NeuN, and brain-derived neurotrophic factor (BDNF) in the hippocampi of Aβ-injected mice. Overall, our results demonstrate that, with further testing in clinical populations, BJIGT may have great utility for the treatment of dementia and especially Alzheimer's disease.

Tetragonia tetragonioides (Pall.) Kuntze Regulates Androgen Production in a Letrozole-Induced Polycystic Ovary Syndrome Model

Tetragonia tetragonioides (Pall.) Kuntze (TTK) is a medicinal plant traditionally used to treat various diseases such as diabetic, inflammatory, and female-related disorders. Polycystic ovary syndrome (PCOS) is a common endocrinological disorder in women of reproductive age, and hyperandrogenism is a prominent feature of PCOS resulting in anovulation and infertility. In this study, we investigated the effects of a TTK extract on androgen generation and regulation of steroidogenic enzymes in vitro and in vivo. Human adrenocortical NCI-H295R cells were used to assess the effects of TTK extract on production of dehydroepiandrosterone and testosterone, as well as the protein expression of steroidogenic enzymes. Further, a letrozole-induced PCOS rat model was used in vivo to assess whether dietary administration of TTK extract restores normal hormones and reduces PCOS symptoms. TTK extract significantly inhibited forskolin (FOR)-induced androgen production in NCI-H295R cells and serum luteinizing hormone, testosterone, and follicular cysts, but not estradiol, were reduced in letrozole-induced PCOS rats orally administered the TTK extract. In addition, TTK extract inhibits androgen biosynthesis through the ERK-CREB signaling pathway, which regulates CYP17A1 or HSD3B2 expression. TTK extract could be utilized for the prevention and treatment of hyperandrogenism and other types of PCOS.

Cytoplasmic translocation of high-mobility group box-1 protein is induced by diabetes and high glucose in retinal pericytes

The aim of the present study was to assess the involvement of the high-mobility group box-1 (HMGB1) protein, receptor for advanced glycation end products (RAGE) and nuclear factor (NF)-κB signaling pathway in the development of diabetic retinopathy. Rat primary retinal pericytes were exposed to 25 mmol/l D-glucose for 48 h. Diabetic retinal vessels were prepared from streptozotocin-induced diabetic rats 12 weeks following the induction of diabetes. The expression of HMGB1 was detected using immunofluorescence staining. The expression of RAGE and the activity of NF-κB were analyzed using western blot and electrophoretic mobility shift assays, respectively. The results showed that HMGB1 was translocated to the cytoplasm of the high glucose-treated pericytes and diabetic retinal pericytes, whereas, in the control cells and the normal retinas, HMGB1 was expressed in the cell nuclei only. The expression of RAGE, a potential receptor for HMGB1, and the activity of NF-κB were also increased in the high glucose-treated pericytes, compared with the normal control cells. In addition, high glucose increased the binding of NF-κB to the RAGE promoter. These findings suggested that the cytoplasmic translocation of HMGB1 may be caused by diabetes and high glucose in retinal pericytes, and that the pathogenic role of HMGB1 may be dependent on the expression of RAGE and activation of NF-κB.

Cnidium officinale extract and butylidenephthalide inhibits retinal neovascularization in vitro and in vivo

BACKGROUND

Retinal neovascularization, which is the pathological growth of new blood vessels, is associated with retinopathy of prematurity, neovascular age-related macular degeneration, diabetic retinopathy and retinal vein occlusion. In this study, we evaluated the effect of an extract of Cnidium officinale Makino (COE) and its bioactive compound, butylidenephthalide (BP), on the migration and tube formation of human umbilical vein endothelial cells (HUVECs), and on retinal pathogenic neovascularization in the oxygen-induced retinopathy (OIR) mouse model.

METHOD

The HUVECs were incubated with COE and BP (0.1-10 μg/ml). The mice were exposed to 75 % oxygen for 5 days starting on the 7(th) postnatal day (P7-P12). Then, the mice were returned to room air and intraperitoneally injected with COE (100 mg/kg) and BP (5 mg/kg) once per day for 5 days (P12-P16). On P17, we measured retinal neovascularization and analyzed the angiogenesis-related proteins expression using protein arrays.

RESULTS

COE and BP inhibit the HUVECs migration and the tube formation in a dose-dependent manner. In addition, COE significantly decreased retinal neovascularization in the OIR mice. COE reduced the expression levels of AREG, ANG, DLL4, Endostatin, IGFBP-2 and VEGF. Additionally, BP also inhibited the retinal neovascularization and down-regulated the expression of AREG, ANG, DLL4 and VEGF.

CONCLUSION

These results suggest that COE and BP exerts antiangiogenic effects on retinal neovascularization by inhibiting the expression of AREG, ANG, DLL4 and VEGF, indicating that antiangiogenic activities of COE may be in part due to its bioactive compound, BP.

Esculetin, a Coumarin Derivative, Inhibits Aldose Reductase Activity in vitro and Cataractogenesis in Galactose-Fed Rats

Naturally occurring coumarin compounds have received substantial attention due to their pharmaceutical effects. Esculetin is a coumarin derivative and a polyphenol compound that is used in a variety of therapeutic and pharmacological strategies. However, its effect on aldose reductase activity remains poorly understood. In this study, the potential beneficial effects of esculetin on lenticular aldose reductase were investigated in galactose-fed (GAL) rats, an animal model of sugar cataracts. Cataracts were induced in Sprague-Dawley (SD) rats via a 50% galactose diet for 2 weeks, and groups of GAL rats were orally treated with esculetin (10 or 50 mg/kg body weight). In vehicle-treated GAL rats, lens opacification was observed, and swelling and membrane rupture of the lens fiber cells were increased. Additionally, aldose reductase was highly expressed in the lens epithelium and superficial cortical fibers during cataract development in the GAL rats. Esculetin reduced rat lens aldose reductase (RLAR) activity in vitro, and esculetin treatment significantly inhibited lens opacity, as well as morphological alterations, such as swelling, vacuolation and liquefaction of lens fibers, via the inhibition of aldose reductase in the GAL rats. These results indicate that esculetin is a useful treatment for galactose-induced cataracts.

OSSC1E-K19, a novel phytochemical component of Osteomeles schwerinae, prevents glycated albumin-induced retinal vascular injury in rats

In the pathophysiology of diabetic retinopathy (DR), advanced glycation end products (AGEs) and vascular endothelial growth factor (VEGF) are thought to have important roles. It is known that VEGF causes a breakdown of the blood‑retinal barrier (BRB) and retinal neovascularization; however, how AGEs affect the retina has largely remained elusive. OSSC1E‑K19 is a novel phytochemical component of Osteomeles schwerinae. The objective of the present study was to evaluate the protective effects of OSSC1E‑K19 on retinal vascular injury in AGE‑modified rat serum albumin (AGE-RSA)-induced retinopathy. AGE-RSA-injected rat eyes were used investigate the protective effects of OSSC1E‑K19 on BRB breakdown. Intravitreal injection of OSSC1E-K19 prevented AGE-RSA-induced BRB breakdown and decreased retinal VEGF expression in retinal vessels. In addition, OSSC1E-K19 inhibited the loss of occludin, a significant tight junction protein. These results supported the potential therapeutic utility of OSSC1E-K19 for retinal vascular permeability diseases.

Extract of Rhizoma Polygonum cuspidatum reduces early renal podocyte injury in streptozotocin‑induced diabetic rats and its active compound emodin inhibits methylglyoxal‑mediated glycation of proteins

Podocyte injury contributes to renal damage and, eventually, to the occurrence of proteinuria in diabetic nephropathy. The aim of the present study was to investigate the effect of an ethanol extract from Rhizoma Polygonum cuspidatum (P. cuspidatum) on proteinuria and podocyte injury, and elucidate the underlying mechanism for streptozotocin (STZ)-induced diabetic nephropathy. The protective effects of P. cuspidatum extract (PCE) on renal podocytes in STZ-induced diabetic rats were also investigated. PCE (100 or 350 mg/kg/day) was administered to STZ-induced diabetic rats for 16 weeks, and blood glucose levels, body weight and proteinuria were measured. A double labeling technique with the terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed and synaptopodin expression was observed. In addition, cleaved caspase-3, methylglyoxal (MGO) and 8-hydroxydeoxyguanosine (8-OHdG) expression levels were measured. STZ-induced diabetic rats developed hyperglycemia and proteinuria. Increased apoptosis of the podocytes and increased cleaved caspase-3, MGO and 8-OHdG expression levels, as well as decreased synaptopodin expression were detected in the glomeruli of STZ-induced diabetic rats. However, treatment with PCE for 16 weeks restored protein levels to normal, and reduced podocyte loss and apoptosis. Levels of caspase-3 and MGO expression, as well as oxidative stress were ameliorated by PCE treatment. In addition, emodin, a biologically active ingredient of PCE, exerted an MGO scavenging effect and inhibited MGO-derived advanced glycation end-product formation. These findings indicate that PCE may be administered to prevent proteinuria and podocyte loss in STZ-induced diabetic rats partly by inhibiting podocyte apoptosis and cleaved caspase-3 expression, and by restoring the balance of oxidative stress and MGO expression.

Sipjeondaebo-tang, a traditional herbal formula, inhibits retinal neovascularization in a mouse model of oxygen-induced retinopathy

Retinal neovascularization is a common pathology in age-related macular degeneration, retinopathy of prematurity and proliferative diabetic retinopathy. Platelet derived growth factor (PDGF) is a vasoactive factor and has been implicated in proliferative retinopathies. Oxygen-induced retinopathy in the mouse is the standard experimental model of proliferative retinopathies. Sipjeondaebo-tang (SDT) is the most widely used traditional herbal formula in East Asia, also known as Shi-Quan-Da-Bu-Tang in Chinese and Juzen-taiho-to in Japanese. SDT has been known to exert anti-angiogenic activities in several tumor models, but the role of SDT in proliferative retinopathies remains unclear. Thus, the object of the present study is to examine the mechanism of action and efficacy of SDT on retinal neovascularization in oxygen-induced ischemic retinopathy (OIR) mice. Neonatal mice at postnatal day 7 (P7) were exposed to 75% concentration of oxygen for 5 days (P7-P12), and then returned to room air from P12 to P17 to induce retinal neovascularization. SDT were administered once per day for 5 consecutive days (P12-P16) by intraperitoneal injection. Retinal neovascularization was measured at P17. We used a protein array to evaluate the expression levels of angiogenic factors. Inhibitory activity of SDT on PDGF-BB/PDGFRβ interaction was evaluated in vitro. Retinal neovascularization in the OIR mice was significantly decreased by SDT. SDT decreased the expression levels of PDGF-BB protein and VEGF mRNA. Moreover, SDT dose-dependently inhibited PDGF-BB/PDGFRβ interaction (IC50 = 388.82 ± 7.31 µg/ml). In conclusion, SDT is a potent inhibitor of retinal neovascularization through inhibiting the pro-angiogenic effect of PDGF-BB.

Anti-glycation and anti-angiogenic activities of 5'-methoxybiphenyl-3,4,3'-triol, a novel phytochemical component of Osteomeles schwerinae

Advanced glycation end products (AGEs) are involved in the development of diabetic complications such as diabetic retinopathy. 5'-methoxybiphenyl-3,4,3'-triol (referred to as K24) was isolated using bioactivity-guided fractionation of Osteomeles schwerinae C. K. Schneid. and identified as a potent AGE inhibitor. To identify the protective effect of K24 on disruption of the blood-retinal barrier, AGE-RSA was intravitreally injected into rat eyes. K24 had an inhibitory effect on AGE-RSA-induced retinal vascular leakage by suppressing the expression of vascular endothelial growth factor (VEGF) and decreasing the loss of occludin. In addition, we examined whether K24 has a preventive effect against retinal pathogenic angiogenesis in an oxygen-induced retinopathy (OIR) mouse model. K24 significantly reduced the retinal non-perfused area and neovascular tufts in the OIR mice. These data indicate that K24 could serve as an innovative pharmaceutical agent to prevent blood-retinal barrier breakage and retinal pathogenic angiogenesis through an anti-VEGF mechanism.

Litsea japonica extract inhibits neuronal apoptosis and the accumulation of advanced glycation end products in the diabetic mouse retina

The retinal accumulation of advanced glycation end products (AGEs) is a condition, which is found in diabetic retinopathy. The purpose of the present study was to investigate the protective effect of Litsea japonica extract (LJE) and to elucidate its underlying protective mechanism in model diabetic db/db mice. Male, 7 -week-old db/db mice were treated with LJE (100 or 250 mg/kg body weight) once a day orally for 12 weeks. The expression levels of AGEs and their receptor (RAGE) were subsequently assessed by immunohistochemistry. An electrophoretic mobility shift assay and southwestern histochemistry were used to detect activated nuclear factor κB (NF-κB). The immunohistochemical analysis demonstrated that LJE significantly reduced the expression levels of the AGEs and RAGE in the neural retinas of the db/db mice. LJE markedly inhibited the apop-tosis of retinal ganglion cells. In addition, LJE suppressed the activation of NF-κB. These results suggested that LJE may be beneficial for the treatment of diabetes-induced retinal neurodegeneration, and the ability of LJE to attenuate retinal ganglion cell loss may be mediated by inhibition of the accumulation of AGEs.

Vaccinium myrtillus extract prevents or delays the onset of diabetes--induced blood-retinal barrier breakdown

Many dietary supplements have been sold through advertising their large number of beneficial effects. The aim of this study was to determine whether bilberries (Vaccinium myrtillus) help to prevent diabetes-induced retinal vascular dysfunction in vivo. V. myrtillus extract (VME; 100 mg/kg) was orally administered to streptozotocin-induced diabetic rats for 6 weeks. All diabetic rats exhibited hyperglycemia, and VME did not affect the blood glucose levels and body weight during the experiments. In the fluorescein-dextran angiography, the fluorescein leakage was significantly reduced in diabetic rats treated with VME. VME treatment also decreased markers of diabetic retinopathy, such as retinal vascular endothelial growth factor (VEGF) expression and degradation of zonula occludens-1, occludin and claudin-5 in diabetic rats. In conclusion, VME may prevent or delay the onset of early diabetic retinopathy. These findings have important implications for prevention of diabetic retinopathy using a dietary bilberry supplement.

Root of Polygonum cuspidatum extract reduces progression of diabetes-induced mesangial cell dysfunction via inhibition of platelet-derived growth factor-BB (PDGF-BB) and interaction with its receptor in streptozotocin-induced diabetic rats

Background

Platelet-derived growth factor–BB (PDGF-BB) is highly expressed in the renal tissues of patients with diabetic nephropathy, and it plays an important role in the initiation and progression of diabetic nephropathy. The aim of this study was to evaluate the protective effects of root of Polygonum cuspidatum extract (PCE) on early renal glomerular proliferation in streptozotocin (STZ)-induced diabetic rats.

Methods

PCE (100, 350 mg/kg/day) was administered to diabetic rats for 16 weeks. Blood glucose and albuminuria were measured. Renal histology, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression levels were also examined.

Results

After 16 weeks of treatment with PCE, severe hyperglycemia and albuminuria were observed in the diabetic rats. The expressions levels of α-SMA and PCNA proteins were significantly increased in the glomeruli of the diabetic rats. The expression levels of PDGF-BB and its receptor expressions were greatly increased in the glomeruli of the diabetic rats. However, PCE markedly reduced albuminuria in the diabetic rats. PCE inhibited α-SMA and PCNA up-regulation and ameliorated PDGF-BB and PEGFR-ß protein expression in the diabetic rats. In addition, the binding of PDGF-BB/PDGFR-ß was inhibited by PCE as shown by an in vitro assay.

Conclusions

These results suggest that PCE has an inhibitory effect on mesangial proliferation in diabetic renal tissues via the inhibition of the interaction of PDGF-BB with its receptor. PCE may have beneficial effects in preventing the progression of diabetic nephropathy.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-477) contains supplementary material, which is available to authorized users.

Extract of Litsea japonica ameliorates blood-retinal barrier breakdown in db/db mice

Loss of blood-retinal barrier (BRB) properties is an important feature in the pathology of diabetic retinopathy. Endothelium integrity is important for the normal vascular function. Litsea japonica (Thunb.) Jussieu is a Korean native plant that is consumed as a vegetable food. In this study, we evaluated the ability of an ethanol extract of L. japonica to prevent retinal vascular leakages in db/db mice, which is an animal model of type II diabetes. L. japonica extracts (LJE, 100 and 250 mg/kg) were administered once a day, orally, for 12 weeks. Vehicle-treated db/db mice exhibited hyperglycemia and retinal vascular leakage. LJE treatment blocked diabetes-induced BRB breakdown and decreased retinal VEGF expression in db/db mice. LJE also inhibited the degradation of occludin, which is an important tight junction protein. These findings support the potential therapeutic usefulness of L. japonica for retinal vascular permeability diseases.

Aminoguanidine protects against apoptosis of retinal ganglion cells in Zucker diabetic fatty rats

AIM

The inhibition of advanced glycation end products (AGEs) and the receptor for AGEs (RAGE) mediated downstream signaling pathways have been suggested to have retinoprotective actions in diabetic retinopathy. Herein, we examined the protective effects of aminoguanidine (AG), an AGEs inhibitor, on diabetes-induced injury of retinal ganglion cells in the Zucker diabetic fatty (ZDF) rats.

MATERIALS AND METHODS

Seven-week-old male ZDF rats were treated with AG (50 mg/kg body weight) once a day orally for 13 weeks. Serum and vitreous concentration of AGEs were examined. Expressions of AGEs and its receptor (RAGE) were assessed by immunohistochemistry. Southwestern histochemistry was used to detect activated nuclear factor (NF)-κB.

RESULTS

At the end of the study, vitreal levels of AGEs were significantly reduced in ZDF rats treated with AG. Similary, immunohistochemical analysis showed that AG significantly reduced the positive areas for AGEs and RAGE. Furthermore, AG strongly inhibited the loss of retinal ganglion cells by apoptosis. AG also suppressed the activation of to NF-κB.

CONCLUSIONS

Our results suggest that AG has retinoprotective properties through not only direct inhibition of AGEs formation but also downregulation of NF-κB.

Extract of Cassiae semen attenuates diabetic nephropathy via inhibition of advanced glycation end products accumulation in streptozotocin-induced diabetic rats

Chronic hyperglycemia leads to the formation of advanced glycation end products (AGEs), which accelerates the development of diabetic complications. Previous studies have shown that extract of Cassiae semen (CS), the seed of Cassia tora, has inhibitory activity on AGEs formation in vitro and reduces transforming growth factor-beta1 (TGF-β1) and extracellular matrix protein expression via inhibition of AGEs-mediated signaling in glomerular mesangial cells. In this study, to examine the preventive effects of CS extract on the development of diabetic nephropathy in vivo, streptozotocin (STZ)-injected diabetic rats were orally administered CS extract (200 mg/kg body weight/day) for 12 weeks. Serum glucose, triglycerides, and total cholesterol in diabetic rats were significantly higher compared to control rats. CS or aminoguanidine (AG) treatment significantly reduced these factors. Proteinuria and creatinine clearance were also significantly decreased in the CS-treated group compared with the untreated diabetic group. The CS-treated group had significantly inhibited COX-2 mRNA and protein, which mediates the symptoms of inflammation in the renal cortex of diabetic rats. Furthermore, histopathological studies of kidney tissue showed that in diabetic rats, AGEs, the receptor for AGEs, TGF-β1, and collagen IV were suppressed by CS treatment. Our data suggest that oral treatment of CS can inhibit the development of diabetic nephropathy via inhibition of AGEs accumulation in STZ-induced diabetic rats.

Expression of heat shock protein 90 in the kidneys of diabetic db/db mice

OBJECTIVE

To identify novel genes regulated in diabetic nephropathy.

MATERIALS AND METHODS

Total RNA from the renal cortex of db/+ and db/db mice was isolated and DNA microarrays specific for diabetes signaling pathways were used for expression profiling. Expression of mRNA and protein was determined by RT-PCR and western blotting. The terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick-end labeling (TUNEL) assay and immunohistochemical staining were assessed in renal cortex of db/db mice.

RESULTS

Microarray data revealed that 7 genes show up- or down-regulated pattern and diabetic mice specifically decreased heat shock protein (Hsp) 90α expression of genes compared to control mice (diabetic mice 0.68 vs. control mice 1 relative density). Expression of Hsp90α mRNA and Hsp90 protein was significantly decreased in the renal cortex of diabetic mice. However, Hsp70 mRNA and protein expression was not changed. Apoptosis was increased in glomeruli of diabetic mice due to increased expression of cleaved caspase-3 and Bax.

CONCLUSIONS

Our results suggest that Hsp 90 expression was decreased in diabetic glomeruli and decreased Hsp90 expression may mediate podocyte apoptosis in type 2 diabetic kidneys.

HyDRa: control of parameters for deterministic polishing

Deterministic hydrodynamic polishing with HyDRa requires a precise control of polishing parameters, such as propelling air pressure, slurry density, slurry flux and tool height. We describe the HyDRa polishing system and prove how precise, deterministic polishing can be achieved in terms of the control of these parameters. The polishing results of an 84 cm hyperbolic mirror are presented to illustrate how the stability of these parameters is important to obtain high-quality surfaces.

The Extract of Litsea japonica Reduced the Development of Diabetic Nephropathy via the Inhibition of Advanced Glycation End Products Accumulation in db/db Mice

Increasing evidence indicates that advanced glycation end products (AGEs) contribute to the pathogenesis of diabetic nephropathy. The aim of this study was to investigate the protective effect of L. japonica extract (LJE) against renal damage in the db/db mouse. LJE (100 or 250 mg/kg per day) was given to diabetic mice for 12 weeks. Body weight, blood glucose levels, glycated hemoglobin (HbA1c) levels, and proteinuria were examined. In in vitro assay of the inhibition of AGE formation, immunohistochemical analysis of podocyte loss and AGE accumulations were performed. In 20-week-old db/db mice, severe hyperglycemia developed, and proteinuria was significantly increased. Diabetes induced markedly morphological alterations to the renal glomerular cells. AGE accumulations and podocyte loss were detected in renal glomeruli. LJE treatment significantly reduced proteinuria and AGE accumulations in diabetic mice. Moreover, the loss of nephrin, an important slit diaphragm component in the kidneys, was restored by LJE treatment. Our studies suggest that LJE might be beneficial for the treatment of diabetic nephropathy. The ability of LJE to attenuate proteinuria and podocyte dysfunction may be mediated by the inhibition of AGE accumulation in the context of diabetic nephropathy in db/db mice.

Ethyl pyruvate prevents methyglyoxal-induced retinal vascular injury in rats

Pyruvate is an endogenous antioxidant substance. The aim of this study was to investigate the protective effects of ethyl pyruvate (EP) on retinal vascular injury in diabetic retinopathy. To investigate the protective effect of EP on vascular cell apoptosis and blood-retinal barrier (BRB) breakage, we have used intravitreally methylglyoxal-(MGO-) injected rat eyes. Apoptosis of the retinal vascular cell that was stimulated by the intravitreal injection of MGO was evidently attenuated by the EP treatment. EP exerts inhibitory effect on MGO-induced vascular cell apoptosis by blocking oxidative injury. In addition, EP treatment prevented MGO-induced BRB breakage and the degradation of occludin, an important tight junction protein. These observations suggest that EP acts through an antioxidant mechanism to protect against oxidative stress-induced apoptosis in retinal vessels.

Glycoxidised LDL induced the upregulation of Axl receptor tyrosine kinase and its ligand in mouse mesangial cells

Aim/Hypothesis

Low-density lipoprotein (LDL) is subjected to glycoxidation in diabetes, and a novel signalling mechanism by which glycoxidised LDL functions in glomerular mesangial cells remains to be ascertained.

Methods

We performed gene expression analysis in mouse glomerular mesangial cells treated with LDL modified by glycation and oxidation (GO-LDL, 100 µg/ml) for 48 h by using DNA microarray analysis and quantitative real-time PCR. We examined the GO-LDL-specific changes in gene and protein expression in mesangial cells and glomeruli of type 2 diabetic Zucker diabetic fatty (ZDF) rats.

Results

By microarray profiling, we noted that GO-LDL treatment increased Axl receptor tyrosine kinase (Axl) mRNA expression (∼2.5-fold, p<0.05) compared with normal LDL (N-LDL) treatment in mesangial cells. Treatment with GO-LDL also increased the protein levels of Axl and its ligand Gas6 as measured by Western blotting. These increases were inhibited by neutralising Axl receptor-specific antibody. Silencing Gas6 by siRNA inhibited GO-LDL-induced Axl expression in mesangial cells. Axl and Gas6 protein were also increased in cells cultured in high glucose (30 mM) or methylglyoxal (200 µM). Gas6 treatment increased the expression and secretion of TGF-β1 protein, a key regulator of extracellular matrix expression in the glomeruli of diabetic kidneys. Immunohistochemical analyses of glomeruli from 20-week-old ZDF rats exhibited increased Axl protein expression. Rottlerin, a selective PKC-δ inhibitor, completely blocked Gas6-induced TGF-β1 expression.

Conclusions/Interpretation

These data suggest that LDL modified by glycoxidation may mediate Axl/Gas6 pathway activation, and this mechanism may play a significant role in the pathogenesis of diabetic nephropathy.

KIOM-79 protects AGE-induced retinal pericyte apoptosis via inhibition of NF-kappaB activation in vitro and in vivo

KIOM-79 is an herbal mixture of parched Puerariae radix, gingered Magnoliae cortex, Glycyrrhizae radix and Euphorbiae radix. In the present study, we determined the efficacy and possible mechanism of KIOM-79 on the advanced glycation end product (AGE)-modified bovine serum albumin (BSA)-induced apoptosis of cultured bovine retinal pericytes and rat retinal pericytes in Zucker diabetic fatty (ZDF) rats. Seven-week-old male ZDF rats were treated with KIOM-79 (50 mg/kg body weight) once a day orally for 13 weeks. KIOM-79 significantly inhibited pericyte apoptosis which were induced by the AGE-BSA treatment. The KIOM-79 treatment markedly suppressed the activation of nuclear factor-kappaB (NF-κB) through the inhibition of inhibitory κB kinase complex. In addition, the oral administration of KIOM-79 inhibited the changes in retinal vasculature (vascular hyperpermeability, acellular capillary). KIOM-79 strongly inhibited pericyte apoptosis, NF-κB activation and the expression of pro-apoptotic Bax and tumor necrosis factor-α. Our results suggest that KIOM-79 may exert inhibitory effects on AGE-induced pericyte apoptosis by blocking NF-κB activation, thereby ameliorating retinal microvascular dysfunction.

Puerarin inhibits the retinal pericyte apoptosis induced by advanced glycation end products in vitro and in vivo by inhibiting NADPH oxidase-related oxidative stress

Retinal pericyte loss is one of the histopathological hallmarks of early diabetic retinopathy. Puerarin (4'-7-dihydroxy-8-beta-d-glucosylisoflavone), which is an isoflavone-C-glucoside, causes various pharmacological effects that include antihyperglycemic and anti-inflammatory activities. In the present study, we determined the efficacy and possible mechanism of puerarin on the advanced glycation end product (AGE)-modified bovine serum albumin (BSA)-induced apoptosis of cultured bovine retinal pericytes and rat retinal pericytes in intravitreally AGE-modified rat serum albumin (RSA)-injected eyes. Puerarin significantly inhibited pericyte apoptosis, the generation of reactive oxygen species (ROS), and NADPH oxidase activity by inhibiting the phosphorylation of p47phox and Rac1 which were induced by the AGE-BSA treatment. The puerarin treatment markedly suppressed the activation of nuclear factor-kappaB (NF-κB). In addition, the in vivo apoptosis of the retinal pericyte of rats that was stimulated by the intravitreal injection of AGE-RSA was evidently attenuated by the puerarin treatment. These results demonstrate that puerarin may exert inhibitory effects on AGE-induced pericyte apoptosis by interfering with the NADPH oxidase-related ROS pathways and blocking NF-κB activation, thereby ameliorating retinal microvascular dysfunction.

Accumulation of argpyrimidine, a methylglyoxal-derived advanced glycation end product, increases apoptosis of lens epithelial cells both in vitro and in vivo

The formation of advanced glycation end products (AGEs) has been considered to be a potential causative factor of injury to lens epithelial cells (LECs). Damage of LECs is believed to contribute to cataract formation. The purpose of this study was to investigate the cytotoxic effect of AGEs on LECs both in vitro and in vivo. We examined the accumulation of argpyrimidine, a methylglyoxal-derived AGE, and the expression of apoptosis-related molecules including nuclear factor-kappaB (NF-κB), Bax, and Bcl-2 in the human LEC line HLE-B3 and in cataractous lenses of Zucker diabetic fatty (ZDF) rats, an animal model of type 2 diabetes. In cataractous lenses from twenty-one-week-old ZDF rats, LEC apoptosis was markedly increased, and the accumulation of argpyrimidine as well as subsequent activation of NF-κB in LECs were significantly enhanced. The ratio of Bax to Bcl-2 protein levels was also increased. In addition, the accumulation of argpyrimidine triggered apoptosis in methylglyoxal-treated HLE-B3 cells. However, the presence of pyridoxamine (an AGEs inhibitor) and pyrrolidine dithiocarbamate (a NF-κB inhibitor) prevented apoptosis in HLE-B3 cells through the inhibition of argpyrimidine formation and the blockage of NF-κB nuclear translocalization, respectively. These results suggest that the cellular accumulation of argpyrimidine in LECs is NF-κB-dependent and pro-apoptotic.

KIOM-79 inhibits aldose reductase activity and cataractogenesis in Zucker diabetic fatty rats

Objectives

KIOM-79, a combination of four plant extracts, has a preventive effect on diabetic nephropathy and retinopathy in diabetic animal models. In this study, we have investigated the inhibitory effects of KIOM-79 on diabetic cataractogenesis.

Methods

We evaluated aldose reductase activity during cataractogenesis using Zucker diabetic fatty (ZDF) rat, an animal model of type 2 diabetes. ZDF rats were treated orally with KIOM-79 (50 mg/kg body weight) once a day for 13 weeks.

Key findings

In vehicle-treated ZDF rats, lens opacity was increased, and lens fibre swelling and membrane rupture were observed. In addition, aldose reductase activity and aldose reductase protein expression in diabetic lens were markedly enhanced. However, the administration of KIOM-79 inhibited the development of diabetic cataract through the inhibition of aldose reductase activity and protein expression in diabetic lenses.

Conclusions

These observations suggested that KIOM-79 was useful against the treatment of diabetic cataractogenesis.

Inhibitory effects of chlorogenic acid on aldose reductase activity in vitro and cataractogenesis in galactose-fed rats

Chlorogenic acid (5-O-caffeoylquinic acid, CA), a phenolic compound found ubiquitously in plants, has antidiabetic effect in diabetic animal models. In this study, we investigated the inhibitory effect of CA on diabetic cataractogenesis. We evaluated the aldose reductase (AR) activity during cataract development in 50% galactose-fed rats, an animal model of sugar cataract. Galactose-fed rats were treated orally with CA (10 and 50 mg/kg body weight) once a day for 2 weeks. In vehicle-treated galactose-fed rats, lens opacity was increased, and lens fiber swelling and membrane rupture were observed. In addition, AR protein was highly expressed in lens epithelial cells and lens cortical fibers of galactose-fed rats. However, CA inhibited the rat AR activity in vitro, and the administration of CA prevented the development of sugar cataract through the inhibition of AR activity. These observations suggest that CA is useful for the treatment of sugar cataract.

The role of high-mobility group box-1 protein in the development of diabetic nephropathy

BACKGROUND/AIMS

The purpose of the experiment reported here was to assess the involvement of high-mobility group box-1 (HMGB1), receptor for advanced glycation end products (RAGE) and nuclear factor (NF)-κB signaling pathway in the development of rat diabetic nephropathy.

METHODS

Diabetes was induced by intraperitoneal streptozotocin injection in 7-week-old male rats. At 20 weeks of age, renal expression of HMGB1 was detected by immunohistochemistry. The expression of RAGE and NF-κB activity was studied by Western blot and electrophoretic mobility shift assay in renal tissues of normoglycemic and diabetic rats, respectively.

RESULTS

HMGB1 was highly expressed in both the cytoplasmic and nuclear patterns in diabetic renal glomerular cells and tubular epithelial cells, although in normal rats, HMGB1 was expressed only in the cell nuclei. The expression of RAGE, a potential receptor for HMGB1, and NF-κB activity were also greater in diabetic than in normal rats. Moreover, diabetes increased the binding of NF-κB to the RAGE promoter.

CONCLUSION

These findings suggest that hyperglycemia-induced HMGB1 release may induce the renal injury in diabetic rats, and that the pathogenic role of HMGB1 might be dependent on RAGE and through activation of NF-κB.

Variant of the anastigmatic telescope with three mirrors for back focal length

In this paper, an optical design is presented for an anastigmatic telescope with back focal length corrected with exact ray tracing to eliminate spherical, coma, and astigmatism aberrations. The telescope is formed of three conical mirrors, two of them polished on the same substratum. The optical design is divided into three stages: we began the design obtaining the Gaussian parameters in a first-order solution; posteriorly, were obtained analytically the three mirrors' asphericity in a third-order design. The final design stage consists of the implementation of the Fermat's principle, the Abbe sine condition, and the Coddington equations for the exact correction for the three aforementioned aberrations.

Protection against advanced glycation end products and oxidative stress during the development of diabetic keratopathy by KIOM-79

OBJECTIVES

KIOM-79 is a mixture of 80% ethanol extracts of parched Puerariae radix, gingered Magnoliae cortex, Glycyrrhizae radix and Euphorbiae radix. The preventive effect of KIOM-79 on the development of diabetic keratopathy has been investigated.

METHODS

Seven-week-old male Zucker diabetic fatty (ZDF) rats were treated with KIOM-79 (50 mg/kg body weight) once a day orally for 13 weeks. The thickness of the cornea was measured and the extent of corneal cell death was detected by a terminal deoxynucleotidyl transferase dUTP nick-end labelling assay. The expression of advanced glycation end products (AGEs), 8-hydroxydeoxyguanosine, nuclear factor-kappaB (NF-κB), Bax and Bcl-2 were evaluated in corneal tissues.

KEY FINDINGS

The administration of KIOM-79 prevented corneal oedema and apoptotic cell death of corneal cells. The accumulation of AGE in corneal tissues was reduced in ZDF rats treated with KIOM-79. Moreover, KIOM-79 attenuated oxidative DNA damage, NF-κB activation and Bax overexpression in the cornea.

CONCLUSIONS

The results suggested that KIOM-79 exhibited corneal protective properties by not only reducing oxidative stress but inhibiting the AGEs/NF-κB downstream signal pathway during the development of diabetic keratopathy.

Involvement of advanced glycation end products, oxidative stress and nuclear factor-kappaB in the development of diabetic keratopathy

BACKGROUND

The purpose of the experiment reported here was to assess the involvement of advanced glycation end products (AGEs), oxidative stress, and nuclear factor kappa-B (NF-κB) activation in the development of diabetic keratopathy.

METHODS

Diabetes was induced by intraperitoneal streptozotocin injection in male Sprague-Dawley rats. The thickness of the cornea was measured. Apoptosis was detected by TUNEL assay and western blot for caspase-3. The expression of AGEs and 8-hydroxydeoxyguanosine (8-OHdG) were studied by immunohistochemistry in corneal tissues of normoglycaemic and diabetic rats. NF-κB activation was evaluated by electrophoretic mobility shift assay and southwestern histochemistry.

RESULTS

Corneal edema was observed in diabetic rats. The thickness of cornea was higher in diabetic than in control rats. AGEs were accumulated in corneal tissues. 8-OHdG and NF-κB were identified in corneal epithelium, stroma and endothelium, and its expressions were greater in diabetic than in those of control rats. Diabetes induces significant alterations in rat corneal tissue structure.

CONCLUSIONS

The higher expression of AGE, 8-OHdG and NF-κB in corneal tissues of diabetic rats suggests that these factors are involved in apoptosis and in subsequent corneal alterations related to diabetic keratopathy.

Lens epithelial cell apoptosis initiates diabetic cataractogenesis in the Zucker diabetic fatty rat

BACKGROUND

It has been suggested that damage of lens epithelial cell (LEC) may play an important role in cataract formation. Nitric oxide is involved in cataract development. Here, we investigated the relationship between LEC damage and iNOS expression in the Zucker diabetic fatty (ZDF) rat.

METHODS

At 21 weeks of age, the eyes were enucleated and the lens opacity was then examined. Apoptosis were detected by TUNEL assay, and the expression of iNOS and NF-kappaB activation were studied by immunohistochemistry and southwestern histochemistry respectively.

RESULTS

In 21-week-old male ZDF rats, cataract was developed, TUNEL-positive LECs were markedly increased, and the expression levels of iNOS mRNA and protein were significantly upregulated. The expression pattern of iNOS was closely correlated with apoptotic change of LECs. In addition, advanced glycation end products (AGEs) were accumulated in cytoplasm of LECs. Activated NF-kappaB was mainly detected in nucleus of LECs.

CONCLUSIONS

The higher expressions of AGEs, NF-kappaB and iNOS in LECs of diabetic rats suggest that these factors are involved in apoptosis of LEC alterations related to diabetic cataract.

Extract of the aerial parts of Aster koraiensis reduced development of diabetic nephropathy via anti-apoptosis of podocytes in streptozotocin-induced diabetic rats

Advanced glycation end products (AGEs) is produced from glycolysis in vivo, which may result in diabetic nephropathy. Podocyte loss has been implicated in the development of diabetic nephropathy. The aim of this study was to investigate the protective effects of Aster koraiensis extract (AKE), on the damage of renal podocytes in streptozotocin (STZ)-induced diabetic rats. AKE (100, 200mg/kg per day) was given to diabetic rats for 13weeks. Blood glucose, glycated haemoglobin (HbA1c), proteinuria and albuminuria were examined. Kidney histopathology, AGEs accumulation, apoptosis, and expression of Bax and Bcl-2 also were examined. In 20-week-old STZ-induced diabetic rats, severe hyperglycemia was developed, and proteinuria and albuminuria were markedly increased. TUNEL-positive signals were highly detected in glomeruli of STZ-induced diabetic rats. However, AKE reduced proteinuria and albuminuria in diabetic rats. AKE prevented AGEs deposition and podocyte apoptosis. Expression of Bax and Bcl-2 protein were restored by AKE treatment in the renal cortex. These results suggested that AKE has an inhibitory effect of AGE accumulation and anti-apoptotic effect in the glomeruli of diabetic rat. AKE could be beneficial in preventing the progression of diabetic nephropathy.