Evaluating the Protective Effects and Mechanisms of Diallyl Disulfide on Interlukin-1ß-Induced Oxidative Stress and Mitochondrial Apoptotic Signaling Pathways in Cultured Chondrocytes.

The protective effects and mechanisms of DADS on IL-1ß-mediated oxidative stress and mitochondrial apoptosis were investigated in C28I2 human chondrocytes. The effect of various concentrations of DADS (1, 5 10, 25, 50, and 100 µM) on C28I2 cell viability was evaluated in different times (2, 4, 8, 16, and 24 h) to obtain the non-cytotoxic concentrations of drug by MTT-assay. The protective effect of non-toxic concentrations of DADS on experimentally induced oxidative stress and apoptosis by IL-1ß in C28I2 was evaluated. The effects of DADS on IL-1ß-induced intracellular ROS production and lipid peroxidation were detected and the proteins expression of Nrf2, Bax, Bcl-2, caspase-3, total and phosphorylated JNK, and P38 MAPKs were analyzed by Western blotting. The mRNA expression of detoxifying phase II/antioxidant enzymes including heme oxygenase-1, NAD(P)H quinine oxidoreductase, glutathione S-transferase-P1, catalase, superoxide dismutase-1, glutathione peroxidase-1, -3, -4 were evaluated by reverse transcription-polymerase chain reaction. DADS in 1, 5, 10, and 25 µM concentrations had no cytotoxic effect after 24 h. Pretreatment with DADS remarkably increased Nrf2 nuclear translocation as well as the genes expression of detoxifying phase II/antioxidant enzymes and reduced IL-1ß-induced elevation of ROS, lipid peroxidation, Bax/Bcl-2 ratio, caspase-3 activation, and JNK and P38 phosphorylation. DADS could considerably reduce IL-1ß-induced oxidative stress and consequent mitochondrial apoptosis, as the major mechanisms of chondrocyte cell death in an experimental model of osteoarthritis. It may be considered as natural product in protecting OA-induced cartilage damage in clinical setting. J. Cell. Biochem. 118: 1879-1888, 2017. © 2017 Wiley Periodicals, Inc.

PRIMA-1 induces caspase-mediated apoptosis in acute promyelocytic leukemia NB4 cells by inhibition of nuclear factor-κB and downregulation of Bcl-2, XIAP, and c-Myc.

Restoration of p53 function triggers cell death and eliminates tumors in vivo. Identification of p53-reactivating small molecules such as PRIMA-1 holds promise for effective new anticancer therapies. Here, we investigated the effects of small molecule PRIMA-1 on cell viability and expression of p53-regulated genes and proteins in the acute promyelocytic leukemia-derived NB4 cell line. Our results showed that PRIMA-1 had antileukemic properties in acute promyelocytic leukemia-derived NB4 cells. PRIMA-1-triggered apoptosis in a dose-dependent and time-dependent manner as indicated by the MTT assay and annexin-V staining. Apoptosis induction by PRIMA-1 was associated with caspase-9, caspase-7 activation and PARP cleavage. p21 protein expression was increased after PRIMA-1 treatment and real-time PCR analysis of proapoptotic p53 target genes indicated upregulation of Bax and Noxa. Western blot analysis showed that IκBα phosphorylation and its degradation were inhibited by PRIMA-1. Moreover, protein expression of nuclear factor-κB-regulated antiapoptotic (Bcl-2 and XIAP) and proliferative (c-Myc) gene products was decreased. Importantly, PRIMA-1 did not show any significant apoptotic effect in normal human peripheral blood mononuclear cells. These in-vitro studies imply that p53 reactivation by small compounds may become a novel anticancer therapy in acute promyelocytic leukemia.

Atorvastatin: an efficient step forward in mesenchymal stem cell therapy of diabetic retinopathy.

Diabetic retinopathy (DR), a leading cause of vision loss and a significant source of morbidity, is the most common ocular complication of prolonged diabetes mellitus. Most therapeutic approaches address DR by preventing or destroying neovasculature; however, this fails to eliminate pathogenic causes. Mesenchymal stem cells (MSCs) are a promising candidate for cell therapy because they have unique regenerative potential and provide an option to manage retinal injuries. Transplantation of MSCs in rats with diabetes induced by streptozocin administration was shown to ameliorate DR. However, the poor viability and homing of MSCs after transplantation may reduce the efficacy of cell therapy. Intravitreal transplantation of MSCs was shown to augment vascular endothelial growth factor (VEGF). More recent studies have found a central role for VEGF in vascular lesion formation in DR and proposed blockage of VEGF as an effective approach to manage DR. Atorvastatin, a 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitor, has been proven to decrease VEGF production of MSCs under hypoxic conditions. It has also been demonstrated that atorvastatin increases the viability of MSCs through the adenosine monophosphate-activated protein kinase-endothelial nitric oxide synthase signaling pathway. There is also evidence that nitric oxide improves homing of MSCs by increasing chemokine-related receptor CXCR4 expression. It could be hypothesized that co-administration of MSCs with atorvastatin may be a significant step forward in development of an efficient MSC therapy of DR through preventing excess VEGF production by MSCs under hypoxic conditions as well as increasing the viability and homing of transplanted MSCs.

Studying the correlation of renin-angiotensin-system (RAS) components and insulin resistance in polycystic ovary syndrome (PCOs).

OBJECTIVE: It is estimated that 5-7% of women of reproductive age have polycystic ovary syndrome (PCOS). Chronic anovulation, hyperandrogenism, and insulin resistance (IR) are the main characters of this complex syndrome. IR, diabetes and obesity are all strongly correlated with PCOS; moreover, the possibility of direct androgen mediated renin-angiotensin system (RAS) stimulation in women with PCOS is also reported. The aim of the present study was to investigate the correlation between RAS, IR and PCOS. STUDY DESIGN: Thirty one women with PCOS, diagnosed by the Rotterdam criteria, were compared with thirty six control subjects. Both case and control groups were evaluated regarding to their basal hormonal profile, fasting blood sugar, IR, angiotensin converting enzyme (ACE) activity, plasma renin activity (PRA) and angiotensin II (AngІІ) levels. RESULTS: Compared to controls both ACE activity (p = 0.04) and AngΙΙ levels (p = 0.01) were significantly higher in case group. No significant differences between patients and controls were found in PRA. The results demonstrated that IR (p = 0.02) and fasting insulin (p = 0.004) were higher in case group, there was also a positive correlation between ACE activity and IR in case group (p = 0.02, r = 0.2). CONCLUSION: These results may suggest that there is an important correlation between ACE activity and IR in patients with PCOS.

Optimization and comparison of two different 3D culture methods to prepare cell aggregates as a bioink for organ printing.

The ultimate goal of tissue engineering is to design and fabricate functional human tissues that are similar to natural cells and are capable of regeneration. Preparation of cell aggregates is one of the important steps in 3D tissue engineering technology, particularly in organ printing. Two simple methods, hanging drop (HD) and conical tube (CT) were utilized to prepare cell aggregates. The size and viability of the aggregates obtained at different initial cell densities and pre-culture duration were compared. The proliferative ability of the cell aggregates and their ability to spread in culture plates were also investigated. In both methods, the optimum average size of the aggregates was less than 500 microm. CT aggregates were smaller than HD aggregates. 5,000 cells per drop HD aggregates showed a marked ability to attach and spread on the culture surface. The proliferative ability reduced when the initial cell density was increased. Comparing these methods, we found that the HD method having better size controlling ability as well as enhanced ability to maintain higher rates of viability, spreading, and proliferation. In conclusion, smaller HD aggregates might be a suitable choice as building blocks for making bioink particles in bioprinting technique.

Investigating the effect of lead acetate on rat bone marrow-derived mesenchymal stem cells toxicity: role of apoptosis.

Lead exposure continues to be a significant public health problem. Osteoporosis, inhibition of fracture healing, and cartilage functional impairment have been reported from lead exposure. Mesenchymal stem cells (MSCs) are a bone marrow population of cells with the ability to differentiate into various cell types, particularly osteocytes and chondrocytes. Despite intensive investigation on the effect of lead poisoning on various cell types, there is very little if any report on the effect of lead on MSCs. The aim of this study, therefore, was to investigate the effect of lead acetate on rat bone marrow derived MSCs toxicity and its mechanism by examining the role of pro- and anti-apoptotic proteins in this process. It was revealed that lead acetate could induce cell death in a dose-dependent manner using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium (MTT) assay. Compared to controls, the significant over-expression of pro-apoptotic proteins, including Bax, caspases-9, -3, and p53, with no significant change in anti-apoptotic Bcl(2) protein were obtained in lead-treated cells using western blotting analysis. There was a significant increase in DNA fragmentation in treated MSCs compared to controls using flow-cytometry. Finally, it might be concluded that lead acetate could induce cell toxicity and apoptosis in MSCs, causing instability in mitochondria and in turn activation of the intrinsic pathway including over-expression of Bax, caspase 9 and caspase 3, leading to DNA damage and activation of P53.

Effect of chronic lead exposure on pro-apoptotic Bax and anti-apoptotic Bcl-2 protein expression in rat hippocampus in vivo.

Despite reduction in environmental lead, chronic lead exposure still possess a public health hazard, particularly in children, with devastating effects on developing CNS. To investigate the mechanism of this neurotoxicity, young and adult rats were used to study whether exposure to 500 ppm concentrations of lead could induce apoptosis in hippocampus. 2-4 and 12-14-week-old rats received lead acetate in concentration of 500 ppm for 40 days. Control animals received deionized distilled water. In lead-treated groups, the blood lead levels were increased by 3-4 folds. Light and electron microscopical study of hippocampus revealed increased apoptotic cells. Western blot analysis of Bax and Bcl-2 (pro- and anti-apoptotic gene products, respectively) indicated higher expression of Bax protein and no significant change in bcl-2 expression and accordingly increased the Bax/Bcl-2 ratio compared to control group, confirming the histological study. In conclusion, these data suggest that neurotoxicity of chronic lead exposure in hippocampus in vivo may partly be due to facilitation of apoptosis.

Isolation, culture, characterization and optimization of human corneal stem cells.

The effects of human versus mouse EGF on cell growth and culture duration were studied to optimize a human limbal stem cells culture method for therapeutical autologous transplantation. Limbal cells were obtained by trypsin digestion and transferred to a culture medium. The time needed to reach full confluence in culture was determined. Specific antibodies to corneal stem cell marker (P63) versus corneal epithelial differentiation marker (K3) were used for histochemical determinations. A high proportion of P63 positive cells (85 +/- 4.6%), and a correspondingly low proportion K3 positive cells (15 +/- 3.8%) indicated that most cultured cells remained undifferentiated and were considered as stem cells (mean +/- SE, n=10). Cultures reached full confluency after 17.3 +/- 1.2 days when the medium was supplemented with human EGF, while 21.7 +/- 1.5 days were needed when the medium was supplemented with mouse EGF. The results showed that limbal stem cells proliferate more easily and reach to full confluency in a shorter time if the medium is supplemented with hEGF rather than with mEGF.

Studying the effect of LPS on cytotoxicity and apoptosis in PC12 neuronal cells: role of Bax, Bcl-2, and Caspase-3 protein expression.

Gram-negative bacteria and their endotoxins may be a causal or complicating factor in many serious diseases. Bacterial lipopolysaccharides (LPS) could potentially be human pathogens. Among the many disorders induced by LPS, neurodegenerative diseases such as Parkinson's are reported and are of great interest. Despite the evidence on LPS-induced neurodegeneration, the exact mechanism is unknown. The purpose of this study was to investigate the cytotoxic effect of LPS and also to examine the involvement of Bax, pro-apoptotic, Bcl-2, anti-apoptotic, and caspase-3, the executioner of apoptosis, protein expression, during LPS-induced apoptosis in neuronal PC12 cells. The cell viability was evaluated by MTT assy. The expression of pro-apoptotic Bax and anti-apoptotic Bcl2 and caspase -3 protein expressions were measured by immunoblotting. The results showed that LPS could reduce cell viability after 72 h in a dose-dependent manner which was statistically significant in concentration of 200 microg/ml. In western blotting analysis, LPS (200 microg/ml) also enhanced expression of pro-apoptotic Bax and pro-caspase-3 proteins compared to controls, while the expression of Bcl-2 protein was not changed significantly. The Bax/Bcl-2 ratio was significantly increased in LPS-treated cells compared to controls. From the present results, it might be concluded that LPS can cause PC12 cell death, in which apoptosis plays an important role, possibly by the mitochondrial pathway through higher expression of the Bax as well as caspase 3 protein.

Effect of short term treatment of L-carnitine on tissue ACE activity in streptozotocin-induced diabetic rats.

Diabetes is commonly related to the both microvascular as well as macrovascular complications. It appears that both metabolic and hemodynamic factors interact to create these problems. In this study the effects of orally administered L-carnitine, a natural amino acid, on ACE activity in streptozotocin (STZ)-induced diabetic rats were investigated. Streptozotocin (60mg/kg body weight) was given intraperitoneally. Fifty male Sprague-Dawley rats were divided into four groups: untreated normal (C), L-carnitine treated normal (CT), untreated diabetics (D), L-carnitine-treated diabetics (DT). CT and DT received daily L-carnitine 1g/kg orally for 3 weeks after inducing diabetes. The ACE activities in aorta, heart and kidney homogenates was measured at the end of 3 weeks. They were significantly increased in D compared to C group (P<0.05) and significantly decreased in aorta, heart and kidney in DT compared to D group. In conclusion, L-carnitine can reduce tissue ACE activity in aorta, heart and kidney in streptozotocin diabetic rats, which may be due to higher NO production.

Studying the effects of lead on DNA fragmentation and proapoptotic bax and antiapoptotic bcl-2 protein expression in PC12 cells.

ABSTRACT The nervous system is one of the most important targets of lead poisoning. Despite decades of study, the exact mechanism of lead toxicity has not been fully elucidated. One of the suggested mechanisms of lead toxicity is induction of apoptosis, which has not been shown yet in some neuronal cells such as pheochromocytoma cells (PC12). Therefore, the present study sought to examine the effect of lead poisoning on apoptosis in PC12 cells as a suitable model of neuronal cell study. The present results showed that lead could induce toxicity in PC12 cells after 24 hours with as little as 1 muM in a concentration-dependent manner. In Western blot analysis, the ratio of Bax/Bcl-2 protein expression in cells incubated with 3, 30, and 90 muM lead acetate significantly increased compared to controls. Additionally, a DNA laddering pattern in lead-treated cells was shown, which could indicate nuclear fragmentation. It might be concluded that lead could cause PC12 cell death, in which apoptosis or programmed cell death plays an important role.

Neuroprotective effect of cerium oxide nanoparticles in a rat model of experimental diabetic neuropathy.

OBJECTIVE: Neuropathies are a nerve disorders that caused by diabetes. Neuropathy affects over 50% of diabetic patients. High blood glucose and their toxic byproducts are the main causes for nerve dysfunction. In the present study, we examined the neroprotective effects of cerium oxide (CeO2) nanoparticles in diabetic rats. METHOD: Rats divided into four groups: control group, diabetic group, the diabetic group treated with CeO2 nanoparticle at a dose of 65mg/kg and diabetic group received CeO2 nanoparticle at a dose of 85mg/kg. Diabetes was induced by single intraperitoneal injection of 65mg/kg streptozotocin (STZ). 8 weeks after the induction of diabetes, body weight and pain sensitivity in all groups were measured. The blood sample was collected for biochemical analysis. The dorsal root ganglion (DRG) neurons were isolated for histopathological stain and morphometric parameters studies. RESULTS: Reduction of body weight, total thiol molecules (TTM), total antioxidant power (TAP) and ADP/ATP ratio in diabetic rat was reversed by CeO2 nanoparticles administration. We showed that lipid peroxidation (LPO) and nociception latency were significantly increased in STZ-treated rats and decreased after CeO2 nanoparticles administration. DRG neurons showed obvious vacuole and various changes in diameter, area and the count of A and B cells in STZ-diabetic rat. CeO2 nanoparticles improved the histopathology and morphological abnormalities of DRG neurons. CONCLUSION: Our study concluded the CeO2 nanoparticles have a protective effect against the development of DN.

Study of correlation between lead-induced cytotoxicity and nitric oxide production in PC12 cells.

Despite reduction in its exposure, lead remains a major health problem. The primary target of lead toxicity is the central nervous system. The cellular, intracellular and molecular mechanisms of lead neurotoxicity are numerous, such as induction of apoptosis and interfering with Ca2+ dependent enzyme like nitric oxide synthase (NOS). To investigate the cytotoxic effect of lead on rat pheochromocytoma (PC12) cells, as a suitable model for neuroscience study, and possible correlation between lead toxicity and nitric oxide (NO) production, this study was performed. The current results showed that lead could induce cytotoxicity as well as NO production in a dose dependent manner in PC12 cells after 24h. The cytotoxicity was positively correlated with increased NOx (nitrite and nitrate) production in these cells. L-NAME, a NOS inhibitor, treatment (2.5 mM) could reverse this cytotoxicity. It can be concluded that lead-induced cytotoxicity in PC12 cells could partly be mediated by higher NO production.

Neuro-protective effects of cerium and yttrium oxide nanoparticles on high glucose-induced oxidative stress and apoptosis in undifferentiated PC12 cells.

OBJECTIVE: Oxidative stress has been recognized as the major factor for the development of diabetes and its complications. Cerium oxide and Yttrium oxide nanoparticles are known as free radicals scavengers. The aim of this study was to investigate the protective effect of CeO2 and Y2O3 on oxidative stress induced by high glucose in undifferentiated rat pheochromocytoma (PC12) cells. METHODS: In this study, undifferentiated PC12 cells were exposed to high glucose (25 mg/ml, 24 hours) and the protective effects of CeO2 and Y2O3 nanoparticles were evaluated. The viability of undifferentiated PC12 cells was determined by MTT assay. The levels of reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate (DCF). The expression levels of pro-apoptotic Bax, anti-apoptotic Bcl-2 and caspase3 proteins were also detected by western blotting. Total antioxidant power (TAP), total thiol molecules (TTM) and lipid peroxidation (LPO) were also evaluated. RESULTS: CeO2 and Y2O3 increased survival of undifferentiated PC12 cells exposed to high glucose-induced oxidative stress. CeO2 and Y2O3 pre-treatment decreased ROS production, LPO, Bax and caspase-3 proteins expression. Both nanoparticles have also increased the TTM and Bcl-2 protein expression. DISCUSSION: These findings suggest that CeO2 and Y2O3 protect the undifferentiated PC12 cells against the oxidative stress and apoptosis induced by high glucose.

Investigation of acute lead poisoning on apoptosis in rat hippocampus in vivo.

Despite decades of study, the exact mechanism of action of lead, a potent neurotoxic agent, have not been fully elucidated. One of the suggested mechanism of lead neurotoxicity is apoptotic cell death. The present study sought to examine the effect of acute lead poisoning on apoptosis in rat hippocampus. Two to four and 12-14 week old rats were treated for 7 days with 15 mg/kg daily dose of lead acetate intraperitoneally. Control animals received distilled water. In treated groups, the blood lead levels was increased by about 17-19-folds. Histological study of hippocampus revealed apoptotic cells, using light and electron microscopy. In Western blot analysis, the ratio of Bax/Bcl-2 protein expression in hippocampus was significantly increased compared to controls. In conclusion, the lead induced cell death in hippocampus in vivo may partly be due to apoptosis.

Study of antihypertensive mechanism of Tribulus terrestris in 2K1C hypertensive rats: role of tissue ACE activity.

Tribulus terrestris is a natural herb used for treating many diseases including hypertension. According to previous reports, aqueous extract of tribulus fruits may have some antihypertensive effect with an unknown mechanism. The present study investigated the antihypertensive mechanism of tribulus in 2K1C hypertensive rats by measurement of circulatory and local ACE activity in aorta, heart, kidney and lung. Four groups of rats were selected; control, sham, operated or hypertensive and tribulus treated hypertensive group. Hypertension was induced using silver clip on renal artery by surgery. Four weeks after surgery, a single daily dose of 10 mg/kg of lyophilized aqueous extract of tribulus fruit were given orally to 2K1C rats for four weeks. ACE activity was determined by high performance liquid chromatography (HPLC). Blood pressure was measured by the tail-cuff method. The systolic blood pressure (SBP) was significantly increased in 2K1C rats compared to control rats. The SBP of tribulus fed hypertensive rats was significantly decreased compared to hypertensive rats. The ACE activity in all tissues of 2K1C rats including: aorta, heart, kidney, lung as well as serum were significantly increased compared to normal rats. The ACE activity in all tissues of tribulus fed hypertensive rats was significantly lower than that of hypertensive rats, which was more pronounced in kidney. These results indicated that there is a negative correlation between consumption of tribulus and ACE activity in serum and different tissues in 2K1C rats.

Study of correlation between elevation of blood pressure and tissue ACE activity during development of hypertension in 1K1C rats.

OBJECTIVES: This study sought to examine the alteration of local angiotensin converting enzyme (ACE) activity in the aortae, heart, kidney and lung as well as plasma during the development of hypertension in one-kidney, one-clip (1K1C) model, a non-renin-dependent model of renovascular hypertension. METHODS: Experiments were carried out 2, 4, 8 and 12 weeks after induction of hypertension in male Sprague-Dawley rats. ACE activity was analyzed by high-performance liquid chromatography (HPLC) and the structural changes in aortae were investigated by measurement of cross-sectional area (CSA). RESULTS: Our results show that ACE activity in aortae and heart was gradually increased with the development of hypertension and was more pronounced at higher blood pressure. In addition, there was a positive correlation between aortic CSA and elevation of blood pressure. CONCLUSIONS: Our findings emphasize the significant role of local ACE, particularly in organs regulating hypertension (aortae and heart) in 1K1C model, in which circulatory renin is known to be unelevated.

Investigation of circulatory and tissue ACE activity during development of lead-induced hypertension.

Prolonged exposure to low levels of lead causes systemic hypertension. Several mechanisms have been proposed to explain lead-induced hypertension. Recently, the etiological role of the renin-angiotensin system (RAS) has been investigated in this context. This study assessed the alterations of circulatory and tissue angiotensin converting enzyme (ACE) activity during development of lead induced hypertension. Male rats were divided to two main groups: lead-treated animals which received lead acetate, 100 ppm, in drinking water for 2, 4, 6, and 8 weeks and a control group given distilled water. The ACE activity in serum and tissues was analyzed by HPLC. The blood pressure gradually increased in correlation with lead exposure with time. The study also revealed significant elevation of local and serum ACE activity in the early phase of lead treatment; however, chronic lead exposure suppressed ACE activity in serum and tissues. These results emphasize the etiological role of ACE activity in the early phase of lead-induced hypertension.

Investigation of antihypertensive mechanism of garlic in 2K1C hypertensive rat.

This study sought to examine the antihypertensive mechanism of garlic in two-kidney-one-clip (2K1C) hypertensive rat. In this study, the effect of garlic on serum and tissue including: aorta, heart, kidney, lung as well as circulatory (serum) ACE activity in 2K1C rats were examined. Four groups of rats were selected: control "CTL", sham-operated "SHAM", hypertensive "H" and garlic-treated hypertensive "GT" group. Hypertension was induced by surgery. Four weeks post-clipping, single daily dose of 50mg of aqueous extract of garlic was given orally to "GT" rats for 4 weeks. Blood pressure was measured by tail-cuff method. ACE activity was determined using HPLC. The systolic blood pressure (SBP) was significantly increased in "H" compared to "CTL" group. In "GT" group, blood pressure was significantly decreased compared to "H" group. The ACE activity in all tissues of "H" group was significantly increased compared to controls which was significantly decreased in garlic-treated compared to non-treated hypertensive rats. These results indicated a negative correlation between consumption of garlic, blood pressure and ACE activity in serum and different tissues in 2K1C rats, suggesting that garlic has a significant blood pressure lowering effect, which could partly be mediated by reduction in ACE activity.

Protective effect of telmisartan against oxidative damage induced by high glucose in neuronal PC12 cell.

Telmisartan is an angiotensin II type 1 receptor blocker and partial agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). Here, we investigated the protective capacity of telmisartan against high glucose (HG)-elicited oxidative damage in PC12 cells. The activity of lactate dehydrogenase (LDH), NADPH oxidase (NOX), superoxide dismutase (SOD), catalase (CAT) as well as the levels of malondialdehyde (MDA), glutathione (GSH), intracellular reactive oxygen species (ROS), cell viability and DNA fragmentation were measured in HG-treated PC12 cells with and without telmisartan co-treatment. Moreover, the direct antioxidant effect of telmisartan was determined by 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay and protein expression of Bax, Bcl-2, cleaved caspase-3 and NOX subunit p47phox by western blotting. Telmisartan exhibited antioxidant activity in the ABTS assay with the IC50 value of 37.5 µM. Pretreatment of PC12 cells with telmisartan, prior to HG exposure, was associated with a marked diminution in cleaved caspase-3 expression, DNA fragmentation, Bax/Bcl-2 ratio, intracellular ROS and MDA levels. Additionally, the cell viability, GSH level, SOD and CAT activity were notably elevated by telmisartan, whereas the activity and the protein expression of NADPH oxidase subunit p47phox were attenuated. Interestingly, co-treatment with GW9662, a PPAR-γ antagonist, partially inhibited the beneficial effects of telmisartan. These findings suggest that telmisartan has protective effects on HG-induced neurotoxicity in PC12 cells, which may be related to its antioxidant action and inhibition of NADPH oxidase. Furthermore, the results show that PPAR-γ activation is involved in the neuroprotective effects of telmisartan.