Effect of necrostatin-1 pre-treatment on postoperative cognitive function in aged rats with chronic pain due to knee arthritis / 中华麻醉学杂志

Objective:To evaluate the effect of necrostatin-1 (Nec-1)pre-treatment on postoperative cognitive function in aged rats with chronic pain due to knee arthritis.Methods:One hundred and twenty healthy male Sprague-Dawley rats, aged 22 months, weighing 550-600 g, were divided into 4 groups ( n=30 each) using a random number table method: chronic pain due to knee arthritis group(group P), chronic pain due to knee arthritis + operation group (group PS), dimethyl sulfoxide (DMSO) + chronic pain due to knee arthritis + operation group (DMSO+ PS group), and necrostatin-1 + chronic pain due to knee arthritis + operation group (Nec-1+ PS group). The inflammation-induced knee arthritis model was developed by injecting monosodium iodoacetate (MIA) into the left joint cavity.The exploratory laparotomy under sevoflurane anesthesia was performed at 12 weeks after intra-articular MIA injection. In Nec-1+ PS group and DMSO+ PS group, necrosstatin-1 6.25 mg/kg and the equal dose of DMSO were intraperitoneally injected at 1 h before surgery, respectively. At 7 days after surgery, the Morris water maze test was used to evaluate the cognitive function, the activation of microglial cells in the dentate gyrus of hippocampus was observed by immunofluorescent staining, and the activation rate of microglia cells was calculated, the necrosis rate of neurons was determined by flow cytometry, the expression of receptor-interacting protein kinase 1 (RIPK1)and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) was determined by Western blot, and the contents of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6 were determined by enzyme-linked immunosorbent assay. Results:Compared with P group, the escape latency was significantly prolonged, the time of staying at the original platform quadrant was shortened, and the number of crossing the original platform was reduced, the activation rate of microglia cells in the hippocampal dentate gyrus and necrosis rate of hippocampal neurons were increased, the expression of RIPK1 and p-MLKL was up-regulated, and the contents of pro-inflammatory factors TNF-α, IL-1β and IL-6 in hippocampus were increased in PS, DMSO+ PS and Nec-1+ PS groups ( P<0.05). Compared with PS group and DMSO+ PS group, the escape latency was significantly shortened, the time of staying at the original platform quadrant was prolonged, and the number of crossing the original platform was increased, the activation rate of microglia cells in the hippocampal dentate gyrus and necrosis rate of hippocampal neurons were decreased, the expression of RIPK1 and p-MLKL was down-regulated, and the contents of pro-inflammatory factors TNF-α, IL-1β and IL-6 in hippocampus were decreased in Nec-1+ PS group ( P<0.05). Conclusions:Necrostatin-1 pre-treatment can improve postoperative cognitive function in aged rats with chronic pain due to knee arthritis, and the mechanism may be related to inhibition of necrosis in hippocampal neurons and reduction of neuroinflammation.

Inhibitory effect of necrostatin-1 on necroptosis of retinal ganglion cells in rats with acute ocular hypertension / 中华实验眼科杂志

Objective:To investigate the inhibitory effect of specific inhibitor of necroptosis necrostatin-1 (Nec-1) on necroptosis of retinal ganglion cells (RGCs) in rats with acute ocular hypertension.Methods:Twenty-four adult male Sprague Dawley rats were randomly divided into normal control group, model control group, Nec-1 treatment group and negative control group by random number table method, with 6 rats in each group.High intraocular pressure (IOP)-induced ischemia and reperfusion model was established through anterior chamber irrigation of 0.9% sodium chloride solution in left eyes of the rats, raising the IOP to 110 mmHg (1 mmHg=0.133 kPa) for 60 minutes.Nec-1 (4 mmol/L, 2 μl) or dimethyl sulfoxide (2 μl) was intravitreally injected immediately in Nec-1 treatment group and negative control group following modeling, respectively, according to grouping.No intervention was administered to the normal control group.Paraffin sections of rat retinas of the left eyes in different groups were prepared seven days after modeling.The retinal structure was observed by hematoxylin-eosin staining, and the expression levels of thymocyte antigen-1 (Thy-1) and glial fibrillary acidic protein (GFAP) were detected via immunohistochemical staining.All animal experiments were approved by an Ethics Committee of Tianjin Union Medical Center (No.2017 Quick audit C01).Results:Seven days after modeling, compared with normal control group, the retinal nerve fiber layer was thinner in model control group and negative control group, and the RGCs were arranged loosely, and cells in the inner nuclear layer were reduced and arranged disorderly, and cells in the outer nuclear layer were normal or enlarged.Compared with model control group and negative control group, the nerve fiber layer was thickened and the number of RGCs was significantly increased in Nec-1 treatment group.The number of Thy-1-positive RGCs was decreased in model control group, negative control group and Nec-1 treatment group than normal control group, and there were more Thy-1-positive RGCs in Nec-1 treatment group than model control group and negative control group.The integrated absorbance ( A) value of GFAP protein in normal control group, model control group, negative control group and Nec-1 treatment group was 47.209±15.311, 116.220±18.194, 116.382±19.020, 92.818±10.236, respectively, showing statistically significant differences among them ( F=24.675, P<0.001). The integrated A value of GFAP protein was significantly increased in model control group, negative control group and Nec-1 treatment group than normal control group, and the integrated A value of GFAP protein in Nec-1 treatment group was lower than that in model control group and negative control group, with statistically significant differences (all at P<0.05). Conclusions:Nec-1 can promote RGCs survival by inhibiting the necroptosis of RGCs in rats with acute intraocular hypertension.

Role and mechanism of necrostin-1 in promoting oxidative stress response of macrophages in high glucose condition / 华西口腔医学杂志

OBJECTIVES@#To investigate the role and molecular mechanism of necrostatin-1 (Nec-1), a specific programmed cell necrosis inhibitor, in promoting the oxidative stress response of macrophages under high glucose (HG) environment.@*METHODS@#Macrophages were cultured in control (5.5 mmol·L@*RESULTS@#The HG group had increased ROS level and MDA activity (@*CONCLUSIONS@#HG promotes oxidative stress on macrophages by upregulating RIP1 expression.

Effect of melittin on programmed necrosis of human hepatocellular carcinoma cell line SMMC￣7721 / 解剖学报

Objective To investigate the lethal effect of melittin on human hepatocellular carcinoma cell line SMMC-7721 and its possible mechanism. Methods MTT assay was used to investigate the killing effect of different concentrations melittin on human hepatocellular carcinoma cells SMMC-7721. Meanwhile, the inhibitory effect of specific programmed necrosis inhibitors necrostain-1(Nec-1) on melittin killing SMMC-7721 cells was detected. Programmed cell necrosis observed by Hoechst 33342 and PI double staining. The necrotosis rate was detected by flow cytometry. Ultrastructural changes of cell was detected by transmission electron microscopy. The expression of receptor interacting protein 1(RIP1) was detected by Western blotting. Results Compared with the control group, the proliferation activity of SMMC-7721 cells was significantly decreased after treatment with different concentrations of melittin for 24 hours (P < 0. 05) . Cells stained in dark blue and red. Cell membrane integrity was destroyed, organelle swelling, organelle membrane was destroy, that demonstrates cell was necrosis. Westen blotting result showed an increased proportion of RIP1 expression in SMMC-7721 cells. Compared with the melittin group, cell proliferation activity was significantly increased, cell necrotosis rate was decreased, and intracellular RIP1 expression was down-regulated in the Nec-1 pretreatment group. Conclusion Melittin induces cell death in SMMC-7721 cells through the RIP1-mediated programmed necrosis pathway.

Protective effect of necrostatin1 on the damage of pancreas islet cells induced by TNFα / 中南大学学报(医学版)

OBJECTIVES@#To investigate whether necrostatin-1 (Nec-1) can protect islet cells from the damage induced by TNF-α.@*METHODS@#After isolation and purification, the neonatal porcine islet cell clusters (NICCs) were divided into 3 groups (islets 10 000 IEQ/group): a Nec-1 group (Nec-1+TNF-α was added to the culture medium), a TNF-α group (TNF-α was added to the culture medium), and a control group (pure medium). The number of cells was observed after 48 h of co-culture. The cell death was evaluated by AO/EB staining. Insulin secretion and DNA of islets were detected by chemiluminescence and nucleic acid quantitative analysis. RT-PCR assay was used to examine the mRNA expressions of insulin gene, glueogan gene and somatostatin gene. Flow cytometry analysis was used to detect the viability of B cells.@*RESULTS@#The number of islets in Nec-1 group, TNF-α group and the control group were (8 425±2 187), (4 325±778), and (7 122±1 558) IEQ, respectively. Compared to the other two groups, the number of dead cells in TNF-α group was greatly increased. The insulin/DNA values in the Nec-1 group, TNF-α group and blank control group were (13.21±3.15), (2.47±0.45), and (7.44±0.97) mIU/mg, respectively. Compared to the TNF-α group and the control group, the mRNA relative expression levels of insulin gene (6.73±1.07), glucagon gene (10.13±1.98), somatostatin gene (8.57±1.11) were significantly increased in the Nec-1 group (all <0.05), the rate of live cells (97.32±1.87)% and live B cells (90.86±3.68)% were increased significantly in the Nec-1 group (all <0.05).@*CONCLUSIONS@#TNF-α can induce neonatal porcine islet cells damage, which is attenuated in the presence of Nec-1. Nec-1 can increase the content of endocrine cells in NICCs.

Interaction between necroptosis and apoptosis in MC3T3-E1 cell death induced by dexamethasone / 南方医科大学学报

OBJECTIVE@#To investigate the relationship between necroptosis and apoptosis in MCET3-E1 cell death induced by glucocorticoids.@*METHODS@#MC3T3-E1 cells were incubated with 10-6 mol/L dexamethasone followed by treatment with the apoptosis inhibitor z-VAD-fmk (40 μmol/L) or the necroptosis inhibitor necrostatin-1 (40 μmol/L) for 2 h. At 72 h after incubation with dexamethasone, the cells were harvested to determine the cell viability using WST-1 assay and the rate of necrotic cells using annexin V/PI double staining; the percentage of apoptotic cells was determined using Hoechst staining. The mitochondrial membrane potential and the level of ATP in the cells were also evaluated. Transmission electron microscopy was used to observe the microstructural changes of the cells. The expressions of RIP-1 and RIP-3 in the cells were detected by Western blotting.@*RESULTS@#At a concentration of 10-6 mol/L, dexamethasone induced both apoptosis and necroptosis in MC3T3- E1 cells. Annexin V/PI double staining showed that inhibition of cell apoptosis caused an increase in cell necrosis manifested by such changes as mitochondrial swelling and plasma membrane disruption, as shown by electron microscopy; Hoechst staining showed that the percentage of apoptotic cells was significantly reduced. When necroptosis was inhibited by necrostatin-1, MC3T3-E1 cells showed significantly increased apoptosis as shown by both AV/PI and Hoechst staining, and such changes were accompanied by changes in mitochondrial membrane potential and ATP level in the cells.@*CONCLUSIONS@#In the process of dexamethasone-induced cell death, necroptosis and apoptosis can transform reciprocally accompanied by functional changes of the mitochondria.

Necroptosis occurs in osteoblasts during tumor necrosis factor-α stimulation and caspase-8 inhibition

Necroptosis is a regulated cell death mechanism. However, it is unknown whether necroptosis is involved in the death of tumor necrosis factor-α (TNF-α)-treated osteoblasts. Therefore, we conducted the study with TNF-α, Nec-1 (a specific inhibitor of necroptosis), and Z-IETD-FMK (a specific inhibitor of apoptosis) to determine whether necroptosis plays a role in the death of TNF-α-treated osteoblast cell line MC3T3-E1. Cell viability, cell death, and lactate dehydrogenase (LDH) release were assayed to evaluate cytotoxicity. Specific marker proteins receptor interacting protein kinase (RIPK3) and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) for necroptosis, and cleaved caspase 3 for apoptosis were detected by western blot, and mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). We found that TNF-α inhibited cell proliferation in a dose- and time-dependent manner. Nec-1 plus Z-IETD-FMK restored cell viability and significantly decreased LDH release. In addition, TNF-α alone increased the cell population of AV+PI−, while Z-IETD-FMK caused a shift in the cell population from AV+PI− to AV+PI+. Furthermore, TNF-α significantly increased protein cleaved caspase 3. TNF-α plus Z-IETD-FMK significantly increased the proteins RIPK3 and MLKL phosphorylation in MC3T3-E1 cells, while the changes in mRNA levels of RIPK3, MLKL, and caspase 3 were not consistent with the changes in the corresponding protein expression levels. In conclusion, TNF-α induced preferentially apoptosis in osteoblast cell line and necroptosis played a decisive role when TNF-α-induced death was inhibited by the inhibitor of apoptosis. Combined treatment with Nec-1 and Z-IETD-FMK protected mouse osteoblasts from death induced by TNF-α.

Receptor interacting protein kinase 1 and receptor interacting protein kinases 3 mediate glutamate induced cell death in HT-22 hippocampal neuronal cells / 中华神经医学杂志

Objective To explore whether receptor interacting protein (RIP)1/RIP3 pathways participate in glutamate induced cell death in HT-22 neuronal cells and investigate the potential neuroprotection ofnecrostatin-1 in glutamate induced cell death in HT-22.Methods (1) In vitro cultured mouse hippocampal neuronal HT-22 cells were divided into control group,zVAD group,necrostatin-1 (Nec-1) group,glutamate group,glutamate+zVAD group,glutamate+zVAD+Nec-1 group and glutamate+Nec-1 group;they were treated with zVAD,Nec-1 and glutamate at the final concentrations of 20 μmol/L,30 μmol/L and 3 mmol/L for 24 h.Cell viability was detected using a luminescence-based commercial kit Cell Titer-Glo (CTG).Necrotic cell death was measured by propidium iodide (PI) and HE stainings.(2) HT-22 cells were divided into control group Ⅰ,glutamate group Ⅰ and glutamate+Nec-1 group Ⅰ;MitoSox Red was used to detect mitochondrial reactive oxygen species (ROS) level.(3) HT-22 cells were divided into control group Ⅱ,glutamate group Ⅱ and glutamate+tertiary butyl-hydroxyanisole (BHA) group;the final concentration of BHA was 100 μmol/L;necrotic cell death was measured by PI and HE stainings after 24 h of treatment.(4) HT-22 cells were divided into RIP3 siRNA and control group Ⅲ,and then,they were transfected with RIP3 siRNA or negative siRNA,respectively;the RIP3 protein expression was determined by Westem blotting after 72 h of treatment.(5) HT-22 cells were divided into negative siRNA+Control,RIP3 siRNA,negative siRNA+glutamate and RIP3 siRNA+glutamate groups;the cells were transfected with RIP3 siRNA or Negative siNRA,respectively;48 h later,the glutamate groups were treated with 3 mmol/L glutamate;PI positive cells and cell viability were measured by PI and HE stainings and CTG at 24 h after glutamate treatment.Results (1) As compared with control group,percentage of PI positive cells was greatly increased and cell viability was decreased in glutamate group and glutamate+zVAD group,with statistically significant differences (P＜0.05);as compared with those in the glutamate group,percentage of percentage of PI positive cells was was significantly decreased and cell viability was statistically increased in glutamate+Nec-1 group (P＜0.05).(2) ROS level in HT-22 cells of the glutamate group was significantly increased than that in the control group Ⅰ (P＜0.05);however,ROS level in HT-22 cells of glutamate+Nec-1 group Ⅰ was significantly decreased than that in glutamate group Ⅰ (P＜0.05).(3)Percentage of PI positive cells in the glutamate group Ⅱ was significantly higher than that in the control group Ⅱ (P＜0.05),and that in the glutamate+BHA group was statistically lower than that in the glutamate group Ⅱ (P＜0.05).(4) The RIP3 protein expression in the RIP3 siRNA group was obviously down-regulated as compared with that in the control group Ⅲ.(5) As compared with those in the negative siRNA group,percentage of PI positive cells was statistically increased and cell viabilities were statistically decreased in glutamate group (P＜0.05);however,percentage of PI positive cells was significantly decreased and cell viability was significantly increased in RIP3 siNRA+glutamate group as compared with those in the glutamate group (P＜0.05).Conclusion RIP1/RIP3 pathway and ROS might mediate glutamate induced cell death in HT-22 cells.

Effects of Nec-1 on necroptosis and retinal ganglion cells in mouse model of retina ischemia reperfusion injury / 眼科新进展

Objective To observe the influence of necrostatin-1 (Nec-1) on necroptosis and retinal ganglion cells (RGC) in mice with retinal ischemia reperfusion injury (RIRI).Methods Together 60 wild-type C57 mice were randomly divided into three groups (n =20),and they were control group,experimental group and blank group.Firstly,as for investigation the effect of Nec-I on necroptosis,15 mice in the blank group left untreated,15 mice in the experimental group were injected with 2 μL Nec-1 (2 mol · L-1) intravitreally,and 15 in the control group without pretreatment.After 4 h,the RIRI model was established by anterior chamber perfusion in the latter two groups.Then retinas in 5 mice in each group were harvested 3 days after ischemia reperfusion injury for Western blot,immunofluorescence quantitative PCR and immunofluorescence staining to detect the expression of mRNA and protein of IL-1β,IL-6,TNF-α,RIP3,RIP1 and Caspase-8.Secondly,the rest of 5 mice in 20 of each group were collected and retrogradely labeled with fluoro-gold (FG) to explored the influence of Nec-1 on RGC.Mice in the blank group left untreated.Mice in the experimental group were injected with 2 μL Nec-1 (2 mol · L-1) intravitreally,while the control group was not treated anything 7 days after fluorescence labeling;after 4 h,the RIRI model was established by anterior chamber perfusion in the two groups.The retinal tissue was harvested and RGC counting was performed 3 days after ischemia reperfusion injury.Results When compared with control group,mRNA expression levels of IL-1β,IL-6,TNF-α,RIP3 and RIP1 in the experimental group were decreased significantly (all P ＜ 0.001),but Caspase-8 mRNA did not change obviously (P =0.654 8).Western blot and immunofluorescence staining showed that RIP3 expression decreased dramatically in the experimental group when compared with the control group.FG labeled RGC counting presented that RGC number of each field in experimental group was significantly larger than that in the control group (P ＜ 0.001).Couclusion Nec-1 can block necroptosis and significantly increase RGC number in mice model of experimental RIRI.

Effects of Nec-1 on necroptosis and retinal ganglion cells in mouse model of retina ischemia reperfusion injury / 眼科新进展

Objective To observe the influence of necrostatin-1 (Nec-1) on necroptosis and retinal ganglion cells (RGC) in mice with retinal ischemia reperfusion injury (RIRI).Methods Together 60 wild-type C57 mice were randomly divided into three groups (n =20),and they were control group,experimental group and blank group.Firstly,as for investigation the effect of Nec-I on necroptosis,15 mice in the blank group left untreated,15 mice in the experimental group were injected with 2 μL Nec-1 (2 mol · L-1) intravitreally,and 15 in the control group without pretreatment.After 4 h,the RIRI model was established by anterior chamber perfusion in the latter two groups.Then retinas in 5 mice in each group were harvested 3 days after ischemia reperfusion injury for Western blot,immunofluorescence quantitative PCR and immunofluorescence staining to detect the expression of mRNA and protein of IL-1β,IL-6,TNF-α,RIP3,RIP1 and Caspase-8.Secondly,the rest of 5 mice in 20 of each group were collected and retrogradely labeled with fluoro-gold (FG) to explored the influence of Nec-1 on RGC.Mice in the blank group left untreated.Mice in the experimental group were injected with 2 μL Nec-1 (2 mol · L-1) intravitreally,while the control group was not treated anything 7 days after fluorescence labeling;after 4 h,the RIRI model was established by anterior chamber perfusion in the two groups.The retinal tissue was harvested and RGC counting was performed 3 days after ischemia reperfusion injury.Results When compared with control group,mRNA expression levels of IL-1β,IL-6,TNF-α,RIP3 and RIP1 in the experimental group were decreased significantly (all P ＜ 0.001),but Caspase-8 mRNA did not change obviously (P =0.654 8).Western blot and immunofluorescence staining showed that RIP3 expression decreased dramatically in the experimental group when compared with the control group.FG labeled RGC counting presented that RGC number of each field in experimental group was significantly larger than that in the control group (P ＜ 0.001).Couclusion Nec-1 can block necroptosis and significantly increase RGC number in mice model of experimental RIRI.