Inhibition of ALDH2 protects PC12 cells against formaldehyde‐induced cytotoxicity: involving the protection of hydrogen sulphide

Formaldehyde (FA), a common environmental contaminant, has toxic effects on the central nervous system (CNS). We have previously found that hydrogen sulphide (H₂S), the third endogenous gaseous mediator, protects neuron against the toxicity of FA. However, the underlying mechanism is poor. Aldehyde‐dehydrogenase‐2 (ALDH2) plays a major role in detoxification of reactive aldehyde in a range of organs and cell types. Therefore, we speculated that H₂S antagonizes FA‐induced neurotoxicity by modulating ALDH2. In the present study, we found that the exposure of PC12 cells to FA causes increase in ALDH2 expression and activity. Daidzin, an inhibitor of ALDH2, significantly antagonizes FA‐exerted cytotoxicity and oxidative stress including the accumulation of intracellular reactive oxygen species (ROS), 4‐hydroxy‐2‐trans‐nonenal (4‐HNE), and malondialdehyde (MDA), in PC12 cells. We also showed that daidzin markedly attenuated FA‐induced apoptosis in PC12 cells. Furthermore, we found that H₂S reverses FA‐elicited upregulation of ALDH2 in PC12 cells. Our results demonstrated the involvement of downregulation of ALDH2 in the protection of H₂S against FA neurotoxicity.     

Formaldehyde induces apoptosis through decreased Prx 2 via p38 MAPK in lung epithelial cells

Formaldehyde (FA) is an important substance that induces sick house syndrome and diseases, such as asthma and allergies. Oxidative stress is involved in the development of respiratory disease, and diverse antioxidants may protect respiratory tract cells from apoptosis. Peroxiredoxin is a pivotal endogenous antioxidant. In the present study, FA induced death in A549 cells, a lung epithelial cell line, in a dose-dependent manner. FA also increased lipid peroxide formation (LPO) in A549 cells, suggesting a role for oxidative stress. Additionally, FA decreased peroxiredoxin 2 (Prx 2) protein levels after a 24 or 48 h exposure to FA. We also examined whether the FA-induced decrease in Prx 2 was associated with apoptosis. Prx 2 overexpression protected against FA-induced cell apoptosis but not necrosis. Prx 2 overexpression blocked FA-induced increase in Bax, a pro-apoptotic molecule, and a decrease in Bcl-2, an anti-apoptotic molecule. Prx 2 overexpression also protected against FA-induced activation of some special apoptosis-associated proteins [caspase-3, caspase-9, and polypeptide poly (ADP-ribose) polymerase (PARP)]. Furthermore, we examined the signaling molecules involved in the FA-induced decrease in Prx 2 expression. The FA-induced decrease in Prx 2 and increase in cell apoptosis was restored by treatment with SB203580 [a p38 mitogen activated protein kinase (MAPK) inhibitor], but not by SP600125 [a c-jun-N-terminal kinase (JNK) inhibitor]. Also, FA-induced events were blocked by treatment with p38 siRNA, but not by scrambled siRNA. Indeed, FA increased p38 MAPK activation, suggesting a role for p38 MAPK in FA action. In conclusion, FA mediated apoptosis in lung epithelial cells by decreasing Prx 2 via p38 MAPK.     

The impact of FANCD2 deficiency on formaldehyde-induced toxicity in human lymphoblastoid cell lines

Formaldehyde (FA), a major industrial chemical and ubiquitous environmental pollutant, has recently been classified by the International Agency for Research on Cancer as a human leukemogen. The major mode of action of FA is thought to be the formation of DNA–protein cross-links (DPCs). Repair of DPCs may be mediated by the Fanconi anemia pathway; however, data supporting the involvement of this pathway are limited, particularly in human hematopoietic cells. Therefore, we assessed the role of FANCD2, a critical component of the Fanconi anemia pathway, in FA-induced toxicity in human lymphoblast cell models of FANCD2 deficiency (PD20 cells) and FANCD2 sufficiency (PD20-D2 cells). After treatment of the cells with 0–150 μM FA for 24 h, DPCs were increased in a dose-dependent manner in both cell lines, with greater increases in FANCD2-deficient PD20 cells. FA also induced cytotoxicity, micronuclei, chromosome aberrations, and apoptosis in a dose-dependent manner in both cell lines, with greater increases in cytotoxicity and apoptosis in PD20 cells. Increased levels of γ-ATR and γ-H2AX in both cell lines suggested the recognition of FA-induced DNA damage; however, the induction of BRCA2 was compromised in FANCD2-deficient PD20 cells, potentially reducing the capacity to repair DPCs. Together, these findings suggest that FANCD2 protein and the Fanconi anemia pathway are essential to protect human lymphoblastoid cells against FA toxicity. Future studies are needed to delineate the role of this pathway in mitigating FA-induced toxicity, particularly in hematopoietic stem cells, the target cells in leukemia.     

N-trans-feruloyltyramine as a melanin biosynthesis inhibitor

In this study, we examined the effect of N-trans-feruloyltyramine (FA) on melanogenesis in mouse B16 melanoma cells. Melanogenesis was inhibited by FA in a dose-dependent manner. FA exhibited a greater potency than kojic acid as a standard inhibitor of melanogenesis. Moreover, treatment of B16 melanoma cells with FA was found to cause marked decreases in the expression levels of tyrosinase. FA-induced downregulation of tyrosinase resulted in suppression of melanin biosynthesis in murine B16 melanoma cells.     

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.     

Pleiotrophin prevents cocaine-induced toxicity in vitro

Pleiotrophin is a cytokine involved in differentiation, survival and repair processes in the central nervous system. Pleiotrophin is upregulated in the brain after administration of different drugs of abuse, thus suggesting a protective role of this cytokine on drug-induced toxicity. We have tested this hypothesis in vitro using NG108-15 cells, a line widely used for neurotoxicity studies. It was found that pleiotrophin (3 and 6 microM) significantly prevents cocaine (5 mM)-induced cytotoxicity as measured by the neutral red test. Similar results were obtained in PC12 cells, which were found to endogenously express both pleiotrophin and its main target, receptor protein tyrosine phosphatase (RPTP) beta/zeta. Blockade of pleiotrophin signaling using anti-pleiotrophin antibodies (2 microg/ml) did not potentiate cocaine-induced toxicity; interestingly, incubation of PC12 cells only with anti-pleiotrophin antibodies significantly reduced cellular viability, thus suggesting an important role of endogenous pleiotrophin signaling in cell survival. The data suggest that pleiotrophin overexpression in response to drugs of abuse may be relevant to prevent drug-induced toxicity.     

Inhibition of ethanol-induced toxicity by tanshinone IIA in PC12 cells

AIM: To observe the effects of tanshinone IIA (Tan IIA) on the neurotoxicity induced by ethanol in PC12 cells and to explore its protective role. METHODS: PC12 cell survival was measured by MTT assay. The formation of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release were detected by 2',7'-dichlorofluorescin (DCF) fluorescence and calorimetric method, respectively. The percentage of cell apoptosis was monitored by flow cytometry. The expression of p53 was detected by immuno-fluorescence and flow cytometry. RESULTS: Ethanol significantly impaired the survival of PC12 cells as demonstrated by MTT assay. Ethanol also induced significant ROS formation and increased LDH release. Pre-incubation with Tan IIA in the culture medium significantly reversed these changes. Ethanol caused cell apoptosis and the upregulation of p53 protein. The anti-apoptosis effects of Tan IIA on ethanol-induced toxicity were accompanied by the downregulation of pro-apoptotic p53 protein expression. CONCLUSION: Tan IIA can protect neurons from apoptosis and might serve as a potential therapeutic drug for neurological disorders induced by ethanol.     

Cadmium induces ferroptosis and apoptosis by modulating miR-34a-5p/Sirt1axis in PC12 cells

Cadmium (Cd) is a potent neurotoxic metal present in the environment and food. In this study, CdCl₂ (2 or 4 μM) induced cytotoxicity and neurotoxicity in PC12 cells, causing decreases in cell viability and NEP protein expression and increase in p-tau protein expression. For the first time, CdCl₂-initiated injury was found to result from the induction of not only apoptosis but also ferroptosis, as evidenced by the increased iron content, ROS production, and mitochondrial membrane potential along with changes in the expressions of iron death-related genes (FTH1, GPX4, ASCL4, PTGS2, and NOX1) and levels of caspase9, Bax, and Bcl-2 proteins. The molecular mechanisms leading to apoptosis and ferroptosis at least included the participation of the miR-34a-5p/Sirt1 axis, in which miR-34a-5p promoted CdCl₂-induced neurotoxicity through targeting Sirt1. Knocking out miR-34a-5p attenuated CdCl₂-induced damage of PC12 cells, cytotoxicity and neurotoxicity. This research provides the underlying molecular mechanisms of CdCl₂-induced damage and asserts the role of miRNAs as critical regulators.     

Downregulation of Parkin Damages Antioxidant Defenses and Enhances Proteasome Inhibition-Induced Toxicity in PC12 Cells

Loss-of-function mutations in the parkin gene have recently been shown to be responsible for autosomal recessive juvenile Parkinsonism. However, the exact mechanism of pathogenesis remains unclear. This study explores the effect of Parkin downregulation on dopaminergic cells in Parkinson’s disease. We generated small interfering RNA plasmids that target the parkin gene and transfected them into PC12 cells to mimic in vivo loss-of-function. We found that these small plasmids were able to effectively inhibit endogenous Parkin expression in PC12 cells. Downregulation of Parkin decreased the amount of glutathione and superoxide dismutase activity without affecting the amount of malondialdehyde. Moreover, Parkin knockdown rendered PC12 cells more susceptible to cell death induced by the proteasome inhibitor lactacystin. These results indicate that downregulation of Parkin may damage the antioxidation defenses of dopaminergic cells and increase their susceptibility to proteasome inhibitor-induced toxicity.     

丙泊酚对布比卡因诱导的PC12细胞毒性和硫氧还蛋白系统的影响

目的：探讨丙泊酚对布比卡因诱导的PC12细胞毒性的保护作用及内源性硫氧还蛋白（Trx）系统在其中的作用。方法：培养的PC12细胞分成四组，正常对照组、丙泊酚组、布比卡因组、丙泊酚＋布比卡因（PB）组，每组6孔。培养6h和24h后，用MTT比色微量分析细胞存活率，测定上清液乳酸脱氢酶（LDH）活性和细胞内硫氧还蛋白还原酶（TrxR）、活性氧（ROS）活性，RT-PCR检测Trx-1 mRNA和TrxR-1 mRNA表达。结果：与正常PC12细胞相比，布比卡因可显著降低细胞存活率（P〈0．01）和细胞内TrxR活性（P〈0．05），增加上清液中LDH活性和细胞内ROS活性（P〈0．05，P〈0．01），明显降低Trx mRAN和Trx mRAN表达（P〈0．05）；丙泊酚对正常PC12细胞无明显影响；与布比卡因组相比，PB组细胞存活率（P〈0．01）和细胞内Trx活性（P〈0．05）明显增加，上清液中LDH活性和细胞内ROS活性显著降低（P〈0．05，P〈0．01），Trx mRAN和Trx mRAN表达明显增加（P〈0．05）。结论：布比卡因对PC12细胞具有毒性作用可能与降低细胞内TrxR活性、增加ROS活性有关，丙泊酚通过保护细胞内Trx系统的活性及清除ROS来减轻布比卡因诱导的PC12细胞毒性。     

PACAP27抑制鱼藤酮诱导细胞凋亡的实验研究

目的探讨垂体腺苷酸环化酶激活肽27(PACAP27)对鱼藤酮诱导的PC12细胞损伤的保护作用。方法诱导分化后的PC12细胞,经不同浓度的鱼藤酮处理后,观察其形态改变;四甲基偶氮唑盐(MTT)法检测细胞活性及代谢状态;磷脂酰丝氨酸外翻法(AnnexinV)检测细胞凋亡,流式细胞术检测细胞凋亡率。结果经鱼藤酮处理24h后PC12细胞活性明显下降,且呈剂量依赖性(P<0.01);PACAP27(10-12～10-7mol·L-1)对鱼藤酮诱导的细胞凋亡具有明显的抑制作用;与鱼藤酮处理组(250nmol·L-1)相比,PACAP27保护组(10-8mol·L-1)AnnexinV和碘化丙啶(propidiumiodide,PI)呈双阳性的晚期凋亡细胞数明显减少;流式细胞仪结果显示,PACAP27可明显减少凋亡细胞的比值,提高细胞的生存率(P<0.01);而PACAP/VIPⅠ型受体拮抗剂PACAP627可逆转这一效应。结论PACAP27可通过PAC1受体介导对鱼藤酮诱导的细胞凋亡进行有效抑制。     

PON-1 carbamylation is enhanced in HDL of uremia patients

High-density lipoprotein (HDL) carbamylation has been known in uremia patients. Paraoxonase-1 (PON-1) is an important HDL protein responsible for HDL anti-oxidant, arylesterase and lactonase activities. PON-1 carbamylation in uremic HDL has never been explored. We isolated HDL from uremia patients and control healthy subjects for study. Sandwich ELISA was used to estimate carbamylated PON-1 protein expression in HDL, and nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) was applied to identify the amino acid in PON-1 carbamylated. PON-1 enzyme activities were estimated by substrates conversion method. HDL anti-oxidant activity was gauged by fluorescence changes of indicator dye in the presence of H₂O₂. Our study results proved that the degree of PON-1 carbamylation was higher in uremic HDL than in control HDL. Sandwich ELISA study showed that carbamylated PON-1 concentration in uremic HDL was 1.49 ± 0.08 fold higher than that in HDL from controls (p < 0.05). The nanoLC-MS/MS showed that the carbamylation of lysine 290 (K290) of PON-1, a residue adjacent to PON-1 activity determining site, was detected in uremic HDL but not detected in control HDL. K290 carbamylation leads to local conformation changes that reduce accessible solvent accessibility. The HDL paraoxonase, arylesterase, and lactonase activities were all significantly lower in uremia patients than in control subjects. Additionally, HDL anti-antioxidant ability was also lower in uremia patients. Carbamylation of PON-1 in uremia patients could be one of the factors in impairing PON-1 enzyme activities and HDL anti-oxidation function.     

In vitro protective effects of pyrroloquinoline quinone on methylmercury-induced neurotoxicity

Methylmercury (MeHg), as a well-known neurotoxicant, has been implicated to induce massive neurodegeneration. Pyrroloquinoline quinone (PQQ) is a novel redox cofactor and also exists in various plants and animal tissues. In vivo as well as in vitro experimental studies have shown that PQQ functions as an essential nutrient or antioxidant. In this study, we demonstrated the protective effects of PQQ on MeHg-induced neurotoxicity in PC12 cells. The results showed that after pretreatment of PC12 cells with PQQ prior to MeHg exposure, the MeHg-induced cytotoxicity was significantly attenuated, and then DNA fragmentation was correspondingly reduced. PQQ prevented the disruption of mitochondrial membrane potential, up-regulated the level of Bcl-2, and consequently inhibited the activation of caspase-3. Moreover, PQQ also decreased the production of ROS and maintained the GSH levels in PC12 cells exposed to MeHg. Thus, these data indicate that PQQ can protect neurons against MeHg-induced apoptosis and oxidative stress via ameliorating the mitochondrial dysfunction. Data from this study provide a new useful strategy for the treatment of neuronal toxicity induced by mercury toxins.     

Neuroprotective effect of clavulanic acid on trimethyltin (TMT)-induced cytotoxicity in PC12 cells

Trimethyltin (TMT) is a short-chain trialkyltin with various applications in industry. In addition, it is a known neurotoxin, producing significant and selective neurodegeneration in the limbic system of both human and animals. Recently, effect of clavulanic acid (CA) in nervous system has been mentioned. Therefore, in this study, the role of CA in TMT-induced toxicity in PC12 cells was evaluated. For this study, PC12 cells were cultured and exposed to different concentrations of CA for 24?h. Then, TMT (20 µM) was added to cells. After that, MTT test was performed to assay cytotoxicity. Reactive oxygen species production (ROS) was determined using 2,7-dichlorofluorescein diacetate (DCFH-DA) method. Additionally, the levels of Bax, Bcl-2, caspase-3, CERB and p-CREB proteins were evaluated using Western blot analysis. The exposure of PC12 cells to TMT reduced cell viability, increased intracellular ROS production, elevated Bax/Bcl-2 ratio and enhanced the expression of caspase-3 (Pro and cleaved forms) protein. Pretreatment of cells with CA before TMT, significantly reduced ROS generation, diminished upregulation of proapoptotic Bax protein and attenuated caspase-3 protein expression. In conclusion, CA exhibited significant neuroprotective effects against neurotoxicity of TMT mainly throughout reduction of ROS production and regulation of proteins, which are involved in apoptosis pathway.     

Tris (1,3‐dichloro‐2‐propyl) phosphate induces toxicity by stimulating CaMK2 in PC12 cells

Tris (1,3‐dichloro‐2‐propyl) phosphate (TDCIPP) is one of the widely used organophosphorus flame retardants (OPFRs), which are regarded as suitable substitutes for brominated flame retardants (BFRs). Previously, we have validated the toxicity of TDCIPP in PC12 cells owing to the induced alterations in GAP43, NF‐H, CaMK2a/2b, and tubulin α/β proteins; however, limited information is currently available on the toxicity and mechanism of TDCIPP. In the present study, cytotoxicity effects were evaluated by exposing PC12 cells to different concentrations of TDCIPP (0–50 μM) for 4 days. To explore the possible mechanisms through which cytotoxicity is induced, changes in intracellular [Ca²⁺]_i levels and the activation of calmodulin dependent protein kinase 2 (CaMK2), c‐Jun N‐terminal kinase (JNK), extracellular regulated protein kinases (ERK1/2), and p38 mitogen‐activated protein kinases (MAPK) pathways were evaluated. Furthermore, PC12 cells were pretreated with CaMK2 inhibitor KN93 to investigate the relationship between TDCIPP‐induced phosphorylation of CaMK2 and activation of JNK, ERK1/2, and p38 MAPK pathways. Our results indicate that TDCIPP‐induced toxicity might be associated with the overload of [Ca²⁺]_i levels, increased phosphorylation of CaMK2, and activation of the JNK, ERK1/2, and p38 MAPK pathways, the lattermost of which was further demonstrated to be partially elicited by the CaMK2 phosphorylation.     

Transient receptor potential vanilloid 1 - a polymodal nociceptive receptor - plays a crucial role in formaldehyde-induced skin inflammation in mice

Formaldehyde (FA) is irritating to the skin and is the main cause of sick building syndrome. However, the cutaneous reaction induced by long-term FA exposure has not been fully investigated. In our previous study, we demonstrated that repeated painting of 2% - 10% FA on mouse ears caused marked ear swelling and increased mRNA expression of transient receptor potential vanilloid 1 (TRPV1) and neurotrophins in the ear. TRPV1 is reported to be involved in neurogenic inflammation; therefore, in the present study, we investigated the role of TRPV1 in FA-induced skin inflammation using TRPV1 gene-knockout mice. Mice were painted with 5% FA once a week for 5 weeks, and ear swelling and mRNA expression were investigated. Ear swelling and increased expression of neurotrophins mRNA by FA provocation in wild-type mice were attenuated by disruption of the TRPV1 gene. Furthermore, painting with a threshold dose of capsaicin, which does not induce ear swelling in intact mice, caused marked ear swelling after painting the ear 5 times with FA, indicating that inflamed tissues after FA application are hypersensitive to various ligands of TRPV1 in mice. These results demonstrated that neurogenic inflammation via TRPV1 and neurotrophins could be involved in FA-induced dermatitis.     

Pivotal role of cAMP‐PKA‐CREB signaling pathway in manganese‐induced neurotoxicity in PC12 cells

Manganese (Mn) plays a critical role in individual growth and development, yet excessive exposure can result in neurotoxicity, especially cognitive impairment. Neuronal apoptosis is considered as one of the mechanisms of Mn‐induced neurotoxicity. Recent evidence suggests that cAMP‐PKA‐CREB signaling regulates apoptosis and is associated with cognitive function. However, whether this pathway participates in Mn‐induced neurotoxicity is not completely understood. To fill this gap, in vitro cultures of PC12 cells were exposed to 0, 400, 500, and 600 μmol/L Mn for 24 hours, respectively. Another group of cells were pretreated with 10.0 μmol/L rolipram (a phosphodiesterase‐4 [PDE4] inhibitor) for 1 hour followed by 500 μmol/L Mn exposure for 24 hours. Flow cytometry, immunofluorescence staining, enzyme‐linked immunosorbent assay, and Western blot analysis were used to detect the apoptosis rate, protein levels of PDE4, cAMP signaling, and apoptosis‐associated proteins, respectively. We found that Mn exposure significantly inhibited cAMP signaling and protein expression of Bcl‐2, while increasing apoptosis rate, protein levels of PDE4, Bax, activated caspase‐3, and activated caspase‐8 in PC12 cells. Pretreatment of rolipram ameliorated Mn‐induced deficits in cAMP signaling and apoptosis. These findings demonstrate that cAMP‐PKA‐CREB signaling pathway‐induced apoptosis is involved in Mn‐induced neurotoxicity.     

Induction and inhibition of testicular germ cell apoptosis by fluoroacetate in rats

Fluoroacetate (FA), an inhibitor of aconitase, is known to lower the intracellular level of adenosine triphosphate (ATP), which recently has been suggested to be a possible determinant of the form of cell death, apoptosis or necrosis. To investigate which form of germ cell death occurs in FA-induced testicular toxicity, adult Sprague Dawley rats were given a single oral dose of FA (0.5 or 1.0 mg/kg) and euthanized at 3, 6, 12, 24, 48, and 72 h thereafter. Germ cell degeneration was histologically first found in early round spermatids at stage I and in spermatogonia at stages II-IV of seminiferous tubules 6 and 12 h, respectively, after dosing. Degenerating spermatogonia exhibited characteristic features of apoptosis as demonstrated by both electron microscopy and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), whereas spermatids did not. At the 24 and 48 h time points, degenerating spermatids were continually present and subsequently formed multinucleated giant cells, while the number of degenerating spermatogonia and TUNEL-labeled spermatogonia was drastically and/or significantly decreased compared to those from the control group, indicating that spontaneous male germ cell apoptosis is inhibited. Coincident with these morphological changes, DNA laddering on gel electrophoresis was apparent only 12 h after dosing. The results demonstrate that FA induces either apoptosis or necrosis of male germ cells in the early stage after dosing and subsequently inhibits spontaneous apoptosis. Received: 12 October 1999 / Accepted: 7 December 1999     

京尼平衍生物对硝普钠诱导的PC12细胞损伤的保护作用

目的探讨京尼平及其衍生物对硝普钠诱导的PC12细胞损伤的保护作用及其作用机制。方法通过62.5~1 000μmol/L硝普钠处理PC12细胞24 h建立细胞损伤模型,造模前2 h给予京尼平衍生物预处理,采用噻唑蓝比色法(MTT)考察京尼平衍生物对PC12细胞存活率的影响。Hoechst染色后观察细胞形态,以DCFH-DA探针和丙二醛(MDA)检测试剂盒分别检测PC12细胞内ROS、MDA水平,RT-PCR法检测PC12细胞抗氧化应激基因水平。结果与对照组比较,硝普钠能剂量相关性地降低PC12细胞的存活,在750μmol/L时具有统计学差异,而10μmol/L 1R-异丙基-6,7-二氢京尼平(化合物4)、1S-异丙基-6,7-二氢京尼平(化合物5)能够明显增加硝普钠诱导PC12细胞损伤后的细胞存活率(P0.05、0.01)。Hoechst染色形态学证实化合物4、5能够明显减少PC12细胞的凋亡。硝普钠诱导PC12细胞内氧化应激水平,化合物4、5能有效地降低ROS、MDA水平,并促进抗氧化酶基因GCLC、GPX、CAT m RNA表达,但对HO-1、Mn SOD基因表达水平无明显影响。结论京尼平衍生物可以抑制硝普钠诱导的PC12细胞损伤和细胞内氧化应激水平,其作用机制可能是通过影响抗氧化酶GCLC、CAT、GPX m RNA表达水平而实现。