Dataset Information

Luteolin alleviates inflammation and autophagy of hippocampus induced by cerebral ischemia/reperfusion by activating PPAR gamma in rats.

ABSTRACT:

Background

Luteolin, a flavonoid compound with anti-inflammatory activity, has been reported to alleviate cerebral ischemia/reperfusion (I/R) injury. However, its potential mechanism remains unclear.

Methods

The binding activity of luteolin to peroxisome proliferator-activated receptor gamma (PPARγ) was calculated via molecular docking analysis. Rats were subjected to middle cerebral artery occlusion and reperfusion (MCAO/R). After reperfusion, vehicle, 25 mg/kg/d luteolin, 50 mg/kg/d luteolin, 10 mg/kg/d pioglitazone, 50 mg/kg/d luteolin combined with 10 mg/kg/d T0070907 (PPARγ inhibitor) were immediately orally treatment for 7 days. ELISA, TTC staining, H&E staining, immunohistochemistry, immunofluorescence and transmission electron microscope methods were performed to evaluate the inflammation and autophagy in damaged hippocampal region. The PPARγ, light chain 3 (LC3) B-II/LC3B-I and p-nuclear factor-κB (NF-κB) p65 proteins expression levels in damaged hippocampal region were analyzed.

Results

Luteolin showed good PPARγ activity according to docking score (score = - 8.2). Luteolin treatment downregulated the infarct area and the pro-inflammatory cytokines levels caused by MCAO/R injury. Moreover, luteolin administration ameliorated neuroinflammation and autophagy in damaged hippocampal region. Pioglitazone plays protective roles similar to luteolin. T0070907 concealed the neuroprotective roles of 50 mg/kg/d luteolin.

Conclusions

Luteolin exerts neuroprotective roles against inflammation and autophagy of hippocampus induced by cerebral I/R by activating PPARγ in rats.

SUBMITTER: Li L

PROVIDER: S-EPMC9248165 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Peroxisome proliferator-activated receptor (PPAR)-gamma modulates substrate metabolism and inflammatory responses. In experimental rats subjected to myocardial ischemia-reperfusion (I/R), thiazolidinedione PPAR-gamma activators reduce infarct size and preserve left ventricular function. Troglitazone is the only PPAR-gamma activator that has been shown to be protective in I/R in large animals. However, because troglitazone contains both alpha-tocopherol and thiazolidinedione moieties, whether PPAR-gamma activation per se is protective in myocardial I/R in large animals remains uncertain. To address this question, 56 pigs were treated orally for 8 wk with troglitazone (75 mg x kg(-1) x day(-1)), rosiglitazone (3 mg x kg(-1) x day(-1)), or alpha-tocopherol (73 mg x kg(-1) x day(-1), equimolar to troglitazone dose) or received no treatment. Pigs were then anesthetized and subjected to 90 min of low-flow regional myocardial ischemia and 90 min of reperfusion. Myocardial expression of PPAR-gamma, determined by ribonuclease protection assay, increased with troglitazone and rosiglitazone compared with no treatment. Rosiglitazone had no significant effect on myocardial contractile function (Frank-Starling relations), substrate uptake, or expression of proinflammatory cytokines during I/R compared with untreated pigs. In contrast, preservation of myocardial contractile function and lactate uptake were greater and cytokine expression was attenuated in pigs treated with troglitazone or alpha-tocopherol compared with untreated pigs. Multivariate analysis indicated that presence of an alpha-tocopherol, but not a thiazolidinedione, moiety in the test compound was significantly related to greater contractile function and lactate uptake and lower cytokine expression during I/R. We conclude that PPAR-gamma activation is not protective in a porcine model of myocardial I/R. Protective effects of troglitazone are attributable to its alpha-tocopherol moiety. These findings, in conjunction with prior rat studies, suggest interspecies differences in the response to PPAR-gamma activation in the heart.

Project description:Oxidative stress plays a key role in cerebral ischemia/reperfusion injury. Artemisinin (ART) has antioxidative stress activity in addition to its powerful antimalarial effects. In this article, we investigated the effect of ART on OGD/R-induced oxidative stress injury and its underlying mechanisms. We used oxygen-glucose deprivation/reoxygenation (OGD/R) to establish an in vitro model of cerebral ischemia/reperfusion (I/R) injury. CCK-8 and lactate dehydrogenase (LDH) release were used to assess cellular damage. Measurement of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and mitochondrial membrane potential (MMP) estimates oxidative stress-induced damage and protection from ART effect. OGD/R treatment aggravated oxidative stress damage, whereas ART reversed the effects of OGD/R. Autophagy is closely related to oxidative stress; in order to confirm whether the antioxidative stress effect of ART is related to PHB2-mediated autophagy, we examined the protein expression of prohibitin 2 (PHB2), TOMM20, p62, and the conversion of microtubule-associated protein light chain 3I (LC3I) to LC3II and found that the protein expression of PHB2, TOMM20, p62, and LC3II/LC3I was significantly correlated with OGD/R treatment. The colocalization of PHB2 and LC3, TOMM20, and LC3 was reduced after OGD/R treatment, and ART reversed this change. After silencing PHB2, the protective effect of ART against OGD/R-induced oxidative stress injury was reduced, the protein expressions of PHB2, TOMM20 and LC3II/LC3I and the colocalization of PHB2 and LC3, TOMM20, and LC3 were decreased. We used chloroquine to block the lysosomal pathway and found that ART increased the conversion of LC3I to LC3II, silencing PHB2 which inhibited the conversion of LC3I to LC3II, and impaired mitophagy. Our findings showed that ART attenuated OGD/R-induced oxidative stress damage through PHB2-mediated mitophagy. To the current knowledge, our study is the first to demonstrate that ART attenuates OGD/R-induced oxidative stress injury through PHB2-mediated autophagy in the human neuroblastoma SH-SY5Y cell line, which provided new insights into the treatment of OGD/R injury.