NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway

Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS) is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss.     

Role of oxidative stress in lysosomal membrane permeabilization and apoptosis induced by gentamicin, an aminoglycoside antibiotic

Gentamicin, an aminoglycoside antibiotic used to treat severe bacterial infections, may cause acute renal failure. At therapeutic concentrations, gentamicin accumulates in lysosomes and induces apoptosis in kidney proximal tubular cells. In gentamicin-treated renal LLC-PK1 cells, acridine orange release from lysosomes, previously interpreted as lysosomal membrane permeabilization, precedes the apoptotic cascade that develops during incubation with gentamicin. However, the link between gentamicin lysosomal accumulation and apoptosis remains unclear. We here examined if reactive oxygen species (ROS) production could account for gentamicin-induced acridine orange release and apoptosis, and the implication of iron in these events. We found that gentamicin induced ROS production prior to, and at lower drug concentrations than required for, acridine orange release and apoptosis. ROS antioxidant or scavenger, catalase, and N-acetylcysteine largely prevented these events. Vital confocal imaging revealed that gentamicin-induced ROS production occurs in lysosomes. Deferoxamine, an iron chelator, which is endocytosed and accumulates in lysosomes, largely prevented gentamicin-induced ROS production as well as apoptosis. Direct evidence for gentamicin-induced permeabilization of lysosomal membrane was provided by showing the release into the cytosol of Lucifer yellow, a membrane-impermeant endocytic tracer with a comparable molecular weight as gentamicin. Altogether, our data demonstrate a key role of lysosomal iron and early ROS production in gentamicin-induced lysosomal membrane permeabilization and apoptosis.     

Protective effects of Ginkgo biloba extract (EGb761) and its constituents quercetin and ginkgolide B against β-amyloid peptide-induced toxicity in SH-SY5Y cells

Ginkgo biloba extract EGb761 has been shown to protect against β-amyloid peptide (Aβ)-induced neurotoxicity but the specific mechanisms remain unclear. In the present study, effects of EGb761 and two of its constituents, quercetin and ginkgolide B, on the cytotoxic action of Aβ (1-42) were tested with human neuroblastoma SH-SY5Y cells. We found that EGb761 was able to block Aβ (1-42)-induced cell apoptosis, reactive oxygen species (ROS) accumulation, mitochondrial dysfunction and activation of c-jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt signaling pathways. Both quercetin and ginkgolide B may be involved in the inhibitory effects of EGb761 on JNK, ERK1/2 and Akt signaling pathways. Ginkgolide B also helped to improve mitochondrial functions but quercetin failed to show this effect. Additional experiments suggest that, protective effects of EGb761 against Aβ toxicity may be associated with its antioxidant and platelet activating factor (PAF) antagonist activities. Quercetin but not ginkgolide B is one of the constituents responsible for the antioxidant action of EGb761. Both quercetin and ginkgolide B may be involved in the PAF antagonist activity of EGb761. Overall, actions of individual EGb761 components provide further insights into direct mechanisms underlying the neuroprotective effects of EGb761.     

Protective effect of alpha-linolenic acid on gentamicin-induced ototoxicity in mice

Alpha-linolenic acid is one of the fatty acids known as omega 3. Previous studies have shown the antioxidant and anti-inflammatory effects of alpha-linolenic acid, which prevented cell damage by inhibiting apoptotic pathway. Also, it is known that gentamicin activates apoptotic mediators and causes necrosis in the kidney. Due to this reason, we planned a study to evaluate the protective effects of alpha-linolenic acid on gentamicin induced ototoxicity by evaluating inflammation and apoptotic mediators. For this purpose, 100?mg/kg gentamicin (i.p; intraperitoneally) and 200?mg/kg alpha-linolenic acid (gavage) are administered to mice for 9?days. On 9th and 10th days, rotarod performance was assessed to test the effect of gentamicin and alpha-linolenic acid treatment on the motor coordination of mice. Gentamicin treatment decreased fall latency of mice and gentamicin treatment together with alpha-linolenic acid increased fall latency of mice. Gentamicin treatment also increased expression of phospholipase A2(plA2), cyclooxygenase-2(COX-2) and inducible nitric oxide syntheses (iNOS). Furthermore, it increased Bax and caspase-3, which are proapoptotic proteins and decreased bcl-2 that is an antiapoptotic protein. Gentamicin treatment together alpha-linolenic acid recovered the change of expression of these enzymes. In conclusion, this study showed that alpha-linolenic acid will be useful to prevent gentamicin-induced ototoxicity by inhibiting apoptosis and inflammation.     

The Ginkgo biloba extract (EGb 761) protects and rescues hippocampal cells against nitric oxide-induced toxicity: involvement of its flavonoid constituents and protein kinase C

An excess of the free radical nitric oxide (NO) is viewed as a deleterious factor involved in various CNS disorders. Numerous studies have shown that the Ginkgo biloba extract EGb 761 is a NO scavenger with neuroprotective properties. However, the mechanisms underlying its neuroprotective ability remain to be fully established. Thus, we investigated the effect of different constituents of EGb 761, i.e., flavonoids and terpenoids, against toxicity induced by NO generators on cells of the hippocampus, a brain area particularly susceptible to neurodegenerative damage. Exposure of rat primary mixed hippocampal cell cultures to either sodium nitroprusside (SNP; 100 microM) or 3-morpholinosydnonimine resulted in both a decrease in cell survival and an increase in free radical accumulation. These SNP-induced events were blocked by either EGb 761 (10-100 microg/ml) or its flavonoid fraction CP 205 (25 microg/ml), as well as by inhibitors of protein kinase C (PKC; chelerythrine) and L-type calcium channels (nitrendipine). In contrast, the terpenoid constituents of EGb 761, known as bilobalide and ginkgolide B, as well as inhibitors of phospholipases A [3-[(4-octadecyl)benzoyl]acrylic acid (OBAA)] and C (U-73122), failed to display any significant effects. Moreover, EGb 761 (50 microm) CP 205 (25 microg/ml), and chelerythrine were also able to rescue hippocampal cells preexposed to SNP (up to 1 mM). Finally, EGb 761 (100 microg/ml) was shown to block the activation of PKC induced by SNP (100 microM). These data suggest that the protective and rescuing abilities of EGb 761 are not only attributable to the antioxidant properties of its flavonoid constituents but also via their ability to inhibit NO-stimulated PKC activity.     

Puerarin attenuates cisplatin-induced apoptosis of hair cells through the mitochondrial apoptotic pathway

Puerarin, one of the main components of Pueraria lobata, has been reported to possess a wide range of pharmacological activities, including anti-inflammatory, antioxidative and anti-apoptotic effects. However, the role of puerarin in ototoxic drug-induced hair cell injury has not been well characterized. This study explored whether puerarin protects against cisplatin-induced hair cell damage and its potential mechanisms. The viability of puerarin-treated HEI-OC1 cells was assessed by CCK8 assay. Reactive oxygen species (ROS) was estimated with flow cytometric analysis using Cellrox Green fluorescent probe. Apoptosis-related protein levels were detected by western blot analysis. Immunostaining of the organ of Corti was performed to determine mice cochlear hair cell survival. Our results showed that puerarin improved cell viability and suppressed apoptosis in the cisplatin-damaged HEI-OC1 cells and cochlear hair cells. Mechanistic studies revealed that puerarin attenuated mitochondrial apoptosis pathway by regulating apoptotic related proteins, such as Bax and cleaved caspase-3, and attenuated ROS accumulation after cisplatin damage. Moreover, puerarin was involved in regulating the Akt pathway in HEI-OC1 cells in response to cisplatin. Our results demonstrated that puerarin administration decreased the sensitivity to apoptosis dependent on the mitochondrial apoptotic pathway by reducing ROS generation, which could be used as a new protective agent against cisplatin-induced ototoxicity.     

Biphasic effect of EGb761 on simulated ischemia-induced rat BMSC survival in vitro and in vivo

AimsThe standardized extract from the leaves of Ginkgo biloba (EGb761) is applied as a phyto-pharmacon in therapy of diverse cardiovascular disorders. However, the effects of EGb761 on bone-marrow mesenchymal stem cells (BMSCs) transplanted into the ischemic myocardium currently remain uncertain. In this study, the dosage-effects of EGb761 on BMSC survival in vitro and in vivo were investigated.Main methodsThe ischemic microenvironment of rat BMSCs was simulated by hypoxia/serum deprivation (SD) and the rat myocardial infarction model was established. The rat BMSCs were cultured under hypoxia/SD or transplanted into the animal ischemic heart. The BMSC apoptosis was determined by FACS and TUNEL assay. Each apoptotic signal molecule's activity was assayed by immunoblot.Key findingsEGb761 showed a biphasic effect on the hypoxia/SD-induced BMSC apoptosis. Low concentration of EGb761 (10–100 μg/ml) aggravated hypoxia/SD-induced apoptosis via Akt inactivation and an enhancement of caspase-9 and caspase-3 expressions, whereas high concentration of EGb761 (500–2000 μg/ml) significantly prevented hypoxia/SD-induced BMSC apoptosis via the activated Akt and the inactivated caspase-9 and caspase-3. The animal study also indicated that the apoptotic index (AI) in the high concentration of EGb761 group was significantly lower than the low concentration of EGb761 group.SignificanceThe biphasic effect of EGb761 is closely related to the PI3K-Akt and caspase-9 signaling pathways. The therapeutic concentration of EGb761 may be one of the vital factors determining the specific action of EGb761 on cell apoptosis. It is of significant clinical implication to investigate the mechanisms of the biphasic effect of EGb761.     

EGb 761 is a neuroprotective agent against beta-amyloid toxicity.

Beta-amyloid (Abeta) deposition likely plays a causal role in the lesions that occur in Alzheimer's disease (AD). The Ginkgo biloba extract EGb 761 is widely prescribed in the treatment of cognitive deficits that are associated with normal and pathological brain aging such as AD. We have investigated here the potential effectiveness of EGb 761 against cell death produced by Abeta fragments on primary cultures of hippocampal cells, these cells being severely damaged in AD. A co-treatment with EGb 761 protected cells against toxicity induced by Abeta fragments in a concentration dependent manner. The effect of EGb 761 was even significant if added up to 8 hr to cells and was shared by its flavonoid fraction CP 205, whereas the terpenes bilobalide and ginkgolide B were ineffective. EGb 761 also displayed protective effects against toxicity produced by either H2O2 or nitric oxide, two neurotoxic agents that possibly mediate Abeta toxicity. Moreover, EGb 761, and to a lesser extent CP 205, completely blocked Abeta-induced events, such as reactive oxygen species accumulation and apoptosis. Taken together, these results and those obtained by other groups highlight the neuroprotective abilities of EGb 761 against dysfunction and death of neurons caused by Abeta deposits.     

5,7-Dihydroxy-4-methylcoumarin modulates the JNK/FoxO1 signaling pathway to attenuate cisplatin-induced ototoxicity by suppressing oxidative stress and apoptosis in vitro

5,7-Dihydroxy-4-methylcoumarin (D4M) is attributed to free radical scavenging effects, with wide application for anti-oxidation. This work aimed to assess D4M's impact on cisplatin-induced ototoxicity. The cell viability was estimated with CCK-8 assay. Apoptosis was detected by the Annexin V-FITC and PI assay. The reactive oxygen species (ROS) level was determined by MitoSOX-Red and CellROX-Green probes. Mitochondrial membrane potential was analyzed with TMRM staining. Immunofluorescence was utilized for hair cells and spiral ganglion neuron detection. Apoptosis-associated proteins were assessed by cleaved caspase-3 and TUNEL staining. These results showed that D4M pretreatment protected hair cells from cisplatin-induced damage, increased cell viability, and decreased apoptosis in House Ear Institute-Organ of Corti1 (HEI-OC1) cells and neonatal mouse cochlear explants. D4M significantly inhibited cisplatin-induced mitochondrial apoptosis and reduced ROS accumulation. In addition, the protective effect of D4M on cisplatin-induced ototoxicity was also confirmed in cochlear hair cells and spiral ganglion neurons in neonatal mice. Mechanistic studies showed that D4M markedly downregulated p-JNK and elevated the expression ratio of p-FoxO1/FoxO1, thereby reducing cisplatin-induced caspase-dependent apoptosis. Meanwhile, D4M-related protection of HEI-OC1 cells was significantly blunted by JNK signaling induction with anisomycin. This study supports the possibility that D4M may be used as a new compound to prevent cisplatin-related hearing loss.     

Acoustic trauma increases cochlear and hair cell uptake of gentamicin

Background

Exposure to intense sound or high doses of aminoglycoside antibiotics can increase hearing thresholds, induce cochlear dysfunction, disrupt hair cell morphology and promote hair cell death, leading to permanent hearing loss. When the two insults are combined, synergistic ototoxicity occurs, exacerbating cochlear vulnerability to sound exposure. The underlying mechanism of this synergism remains unknown. In this study, we tested the hypothesis that sound exposure enhances the intra-cochlear trafficking of aminoglycosides, such as gentamicin, leading to increased hair cell uptake of aminoglycosides and subsequent ototoxicity.

Methods

Juvenile C57Bl/6 mice were exposed to moderate or intense sound levels, while fluorescently-conjugated or native gentamicin was administered concurrently or following sound exposure. Drug uptake was then examined in cochlear tissues by confocal microscopy.

Results

Prolonged sound exposure that induced temporary threshold shifts increased gentamicin uptake by cochlear hair cells, and increased gentamicin permeation across the strial blood-labyrinth barrier. Enhanced intra-cochlear trafficking and hair cell uptake of gentamicin also occurred when prolonged sound, and subsequent aminoglycoside exposure were temporally separated, confirming previous observations. Acute, concurrent sound exposure did not increase cochlear uptake of aminoglycosides.

Conclusions

Prolonged, moderate sound exposures enhanced intra-cochlear aminoglycoside trafficking into the stria vascularis and hair cells. Changes in strial and/or hair cell physiology and integrity due to acoustic overstimulation could increase hair cell uptake of gentamicin, and may represent one mechanism of synergistic ototoxicity.     

Effect of Different Gentamicin Dose on the Plasticity of the Ribbon Synapses in Cochlear Inner Hair Cells of C57BL/6J Mice

Faithful information transfer at the hair cell afferent synapse requires synaptic transmission to be both reliable and temporally precise. The release of neurotransmitter must exhibit both rapid on and off kinetics to accurately follow acoustic stimuli with a periodicity of 1?ms or less. To ensure such remarkable temporal fidelity, the cochlear hair cell afferent synapse undoubtedly relies on unique cellular and molecular specializations. To study effects of different doses of gentamicin on the changes of synaptic ribbons of cochlear inner hair cells (IHCs) in mice, the availability of genetic information, transgenic and knock-out animals make the C57BL/6J mouse a primary model in biomedical research. Aminoglycoside ototoxicity, however, has rarely been studied in mature mice because they are considered highly resistant to the drugs. This study presents models for gentamicin ototoxicity in adult C57BL/6J mouse strains. Five-week-old mice were injected intraperitoneally once daily with 50?C300?mg gentamicin base/kg body weight for 7?days. Higher doses of gentamicin appear to be associated with earlier hearing damage in C57BL/6J mice, although not necessarily with more severe damage. At 200?mg/kg, gentamicin appears to induce significant hearing damage while not significantly affect the animal??s general condition. Therefore, 200?mg/kg may be an ideal dose for ototoxicity modeling in C57BL/6J mice using gentamicin. In the early period of different dose of gentamicin effect, when the number of hair cells had not changed, the number changes of IHC ribbon synapses had taken place. Through the number of ribbon synapses changing, IHCs increased or decreased connections with spiral ganglion nerves (SGNs). The ribbon synapses played a compensatory role for gentamicin ototoxicity, while this effect was not sufficient to maintain the normal threshold of hearing.     

Hypoxia-Inducible Factor Activation Protects the Kidney from Gentamicin-Induced Acute Injury

Gentamicin nephrotoxicity is one of the most common causes of acute kidney injury (AKI). Hypoxia-inducible factor (HIF) is effective in protecting the kidney from ischemic and toxic injury. Increased expression of HIF-1α mRNA has been reported in rats with gentamicin-induced renal injury. We hypothesizd that we could study the role of HIF in gentamicin-induced AKI by modulating HIF activity. In this study, we investigated whether HIF activation had protective effects on gentamicin-induced renal tubule cell injury. Gentamicin-induced AKI was established in male Sprague-Dawley rats. Cobalt was continuously infused into the rats to activate HIF. HK-2 cells were pre-treated with cobalt or dimethyloxalylglycine (DMOG) to activate HIF and were then exposed to gentamicin. Cobalt or DMOG significantly increased HIF-1α expression in rat kidneys and HK-2 cells. In HK-2 cells, HIF inhibited gentamicin-induced reactive oxygen species (ROS) formation. HIF also protected these cells from apoptosis by reducing caspase-3 activity and the amount of cleaved caspase-3, and -9 proteins. Increased expression of HIF-1α reduced the number of gentamicin-induced apoptotic cells in rat kidneys and HK-2 cells. HIF activation improved the creatinine clearance and proteinuria in gentamicin-induced AKI. HIF activation also ameliorated the extent of histologic injury and reduced macrophage infiltration into the tubulointerstitium. In gentamicin-induced AKI, the activation of HIF by cobalt or DMOG attenuated renal dysfunction, proteinuria, and structural damage through a reduction of oxidative stress, inflammation, and apoptosis in renal tubular epithelial cells.     

Apoptosis Induced by Ginkgo biloba (EGb761) in Melanoma Cells Is Mcl-1-Dependent

Melanoma is an aggressive skin cancer. Unfortunately, there is currently no chemotherapeutic agent available to significantly prolong the survival of the most patients with metastatic melanomas. Here we report that the Ginkgo biloba extract (EGb761), one of the most widely sold herbal supplements in the world, potently induces apoptosis in human melanoma cells by disturbing the balance between pro- and anti-apoptosis Bcl-2 family proteins. Treatment with EGb761 induced varying degrees of apoptosis in melanoma cell lines but not in melanocytes. Induction of apoptosis was caspase-dependent and appeared to be mediated by the mitochondrial pathway, in that it was associated with reduction in mitochondrial membrane potential and activation of Bax and Bak. Although EGb761 did not cause significant change in the expression levels of the BH3-only Bcl-2 family proteins Bim, Puma, Noxa, and Bad, it significantly downregulated Mcl-1 in sensitive but not resistant melanoma cells, suggesting a major role of Mcl-1 in regulating apoptosis of melanoma cells induced by EGb761. Indeed, siRNA knockdown of Mcl-1 enhanced EGb761-induced apoptosis, which was associated with increased activation of Bax and Bak. Taken together, these results demonstrate that EGb761 kills melanoma cells through the mitochondrial apoptotic pathway, and that Mcl-1 is a major regulator of sensitivity of melanoma cells to apoptosis induced by EGb761. Therefore, EGb761 with or without in combination with targeting Mcl-1 may be a useful strategy in the treatment of melanoma.     

EGb761 Provides a Protective Effect against Aβ1-42 Oligomer-Induced Cell Damage and Blood-Brain Barrier Disruption in an In Vitro bEnd.3 Endothelial Model

Alzheimer’s disease (AD) is the most common form of senile dementia which is characterized by abnormal amyloid beta (Aβ) accumulation and deposition in brain parenchyma and cerebral capillaries, and leads to blood-brain barrier (BBB) disruption. Despite great progress in understanding the etiology of AD, the underlying pathogenic mechanism of BBB damage is still unclear, and no effective treatment has been devised. The standard Ginkgo biloba extract EGb761 has been widely used as a potential cognitive enhancer for the treatment of AD. However, the cellular mechanism underlying the effect remain to be clarified. In this study, we employed an immortalized endothelial cell line (bEnd.3) and incubation of Aβ_1–42 oligomer, to mimic a monolayer BBB model under conditions found in the AD brain. We investigated the effect of EGb761 on BBB and found that Aβ_1–42 oligomer-induced cell injury, apoptosis, and generation of intracellular reactive oxygen species (ROS), were attenuated by treatment with EGb761. Moreover, treatment of the cells with EGb761 decreased BBB permeability and increased tight junction scaffold protein levels including ZO-1, Claudin-5 and Occludin. We also found that the Aβ_1–42 oligomer-induced upregulation of the receptor for advanced glycation end-products (RAGE), which mediates Aβ cytotoxicity and plays an essential role in AD progression, was significantly decreased by treatment with EGb761. To our knowledge, we provide the first direct in vitro evidence of an effect of EGb761 on the brain endothelium exposed to Aβ_1–42 oligomer, and on the expression of tight junction (TJ) scaffold proteins and RAGE. Our results provide a new insight into a possible mechanism of action of EGb761. This study provides a rational basis for the therapeutic application of EGb761 in the treatment of AD.     

CLIMP-63 is a gentamicin-binding protein that is involved in drug-induced cytotoxicity

Aminoglycoside-induced nephrotoxicity and ototoxicity is a major clinical problem. To understand how aminoglycosides, including gentamicin, induce cytotoxicity in the kidney proximal tubule and the inner ear, we identified gentamicin-binding proteins (GBPs) from mouse kidney cells by pulling down GBPs with gentamicin–agarose conjugates and mass spectrometric analysis. Among several GBPs specific to kidney proximal tubule cells, cytoskeleton-linking membrane protein of 63 kDa (CLIMP-63) was the only protein localized in the endoplasmic reticulum, and was co-localized with gentamicin-Texas Red (GTTR) conjugate after cells were treated with GTTR for 1 h. In western blots, kidney proximal tubule cells and cochlear cells, but not kidney distal tubule cells, exhibited a dithiothreitol (DTT)-resistant dimer band of CLIMP-63. Gentamicin treatment increased the presence of DTT-resistant CLIMP-63 dimers in both kidney proximal (KPT11) and distal (KDT3) tubule cells. Transfection of wild-type and mutant CLIMP-63 into 293T cells showed that the gentamicin-dependent dimerization requires CLIMP-63 palmitoylation. CLIMP-63 siRNA transfection enhanced cellular resistance to gentamicin-induced toxicity, which involves apoptosis, in KPT11 cells. Thus, the dimerization of CLIMP-63 is likely an early step in aminoglycoside-induced cytotoxicity in the kidney and cochlea. Gentamicin also enhanced the binding between CLIMP-63 and 14-3-3 proteins, and we also identified that 14-3-3 proteins are involved in gentamicin-induced cytotoxicity, likely by binding to CLIMP-63.     

Alpha-lipoic acid protects against cisplatin-induced ototoxicity via the regulation of MAPKs and proinflammatory cytokines

Cisplatin is an effective antineoplastic drug that is widely used to treat various cancers; however, it causes side effects such as ototoxicity via the induction of apoptosis of hair cells in the cochlea. Alpha-lipoic acid (ALA) has been reported to exert a protective effect against both antibiotic-induced and cisplatin-induced hearing loss. Therefore, this study was conducted to (1) elucidate the mechanism of the protective effects of ALA against cisplatin-induced ototoxicity using in vitro and ex vivo culture systems of HEI-OC1 auditory cells and rat cochlear explants and (2) to gain additional insight into the apoptotic mechanism of cisplatin-induced ototoxicity. ALA pretreatment significantly reduced apoptotic cell death of the inner and outer hair cells in cisplatin-treated organ of Corti explants and attenuated ototoxicity via marked inhibition of the increase in the expression of IL-1β and IL-6, the phosphorylation of ERK and p38, the degradation of IκBα, the increase in intracellular levels of ROS, and the activation of caspase-3 in cisplatin-treated HEI-OC1 cells. This study represents the first histological evaluation of the organ of Corti following treatment with ALA, and these results indicate that the protective effects of ALA against cisplatin-induced ototoxicity are mediated via the regulation of MAPKs and proinflammatory cytokines.     

银杏叶提取物对过氧化氢诱导的星形胶质细胞氧化损伤的保护作用

目的 研究银杏叶提取物（EGb761）对H2O2所致星形胶质细胞氧化损伤的保护作用。方法 用不同浓度的EGb761预处理细胞,再加入H2O2,通过噻唑蓝（MTT）实验、线粒体跨膜电位（△ψm）及细胞色素C释放实验、DNA损伤实验及半胱氨酰天冬氨酸特异性蛋白酶-3（Caspase-3）活性测定,观察EGb761对细胞存活率、线粒体膜通透性、DNA氧化损伤及Caspase-3活性的影响。结果 EGb761能明显降低Hz02对星形胶质细胞的氧化损伤,提高细胞的存活率;维持线粒体膜的完整性,抑制跨膜电位的耗散和细胞色素C的释放;抑制Caspase-3的活化和DNA的降解。结论 EGb761具有清除活性氧,减轻H2O2所致星形胶质细胞的氧化损伤,对星形胶质细胞有保护作用。