Relationship between NogoA/NgR1/RhoA signaling pathway and the apoptosis of cerebral neurons after cerebral infarction in rats
Authors: C-R Zhang
M Zhang
Y-X Xie
F Chen
Journal: European review for medical and pharmacological sciences (2020)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: NogoA; NgR1; RhoA; apoptosis; neurons
Affiliations: Department of Minimally Invasive Interventional Treatment Center, Department of Outpatient, Department of Neurosurgery; Qingdao Municipal Hospital (Group), Qingdao, China. .

Abstract:  Objective: The aim of this study was to investigate the effect and the mechanism of the NogoA/NgR1/RhoA signaling pathway on the apoptosis of neurons in cerebral infarction (CI) rats. Our findings might provide references for clinical prevention and treatment of CI. Materials and methods: A total of 60 adult male Wistar rats were randomly divided into 3 groups, including: Sham operation group (Sham group), CI group, and CI + NogoA gene knockout group (CI + NogoA KO group) using a random number table. The model of CI was successfully constructed using suture method in rats of CI group and CI + NogoA KO group. Only blood vessels were exposed in Sham group. At 2 days after CI operation, the rats were killed, and brain tissues were collected. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting were used to detect the messenger ribonucleic acid (mRNA) and protein expression levels of NogoA/NgR1/RhoA in brain lesion tissues of rats in the three groups, respectively. Subsequently, the pathological damage of brain tissues was detected via hematoxylin and eosin (H&amp;E) staining. TTC staining was carried out to evaluate the infarction area in each group. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was conducted to measure the apoptosis level of neurons in brain tissues of rats in each group. Additionally, the level of Nissl's body in brain tissues of each group was examined by Nissl staining. Furthermore, the expression level of the platelet-derived growth factor (PDGF) in brain tissues of rats in the three groups was measured via immunohistochemistry. Results: The mRNA and protein expression levels of the NogoA/NgR1/RhoA signaling pathway in brain tissues of rats in CI group increased significantly (p&lt;0.05). NogoA KO could significantly reduce the infarction area of brain tissues in rats (p&lt;0.05). H&amp;E staining and Nissl's body staining revealed that neurons in the brain tissues of rats showed evident edema and disordered arrangement after CI. Meanwhile, the number of Nissl's body was remarkably reduced. However, after KO of NogoA, brain tissue damage was significantly alleviated in rats, and the number of Nissl's body increased remarkably at the same time (p&lt;0.05). According to TUNEL staining results, inhibiting NogoA could notably reverse CI-induced apoptosis of neurons in brain tissues of rats (p&lt;0.05). Immunohistochemical staining results demonstrated that the expression of PDGF in brain tissues of rats in CI group decreased markedly, whereas was significantly elevated in rats of CI + NogoA KO group (p&lt;0.05). Conclusions: The expression of the NogoA/NgR1/RhoA signaling pathway was significantly elevated in brain tissues of CI rats. Furthermore, suppressing the NogoA/NgR1/RhoA signaling pathway could reduce CI-induced apoptosis of neurons in rats. 

Retracted: No

PubPeer comments:
 Please compare *[below]* Figure 5 ,  Nissl staining results in CI area of rats in each group (200u00d7). Sham operation group (Sham group), CI group and CI + NogoA gene KO group (CI+ NogoA KO group) , with *[above]* Figure 3 from [Wang et al (2019)] ,  Nissl staining results in each group. Sham group: Sham-operation group, CIR group: cerebral ischemia-reperfusion group, miR-34a siRNA group: miR-34a knockdown group . ![file] , 
 Please compare *[below]* Fig 7  Effect of NogoA KO on the expression of PDGF in brain tissues of rats (400u00d7). Sham operation group (Sham group), CI group and CI + NogoA gene KO group (CI+ NogoA KO group) with *[above]* Figure 6 from Wang et al (2019),  PDNF immumohistochemical staining results of brain tissues in each group. Sham group: Sham-operation group, CIR group: cerebral ischemia-reperfusion group, miR-34a siRNA group: miR-34a knockdown group group . ![file] , 
 Retracted, [March 2022] . --------------------- The article u201cRelationship between NogoA NgR1 RhoA signaling pathway and the apoptosis of cerebral neurons after cerebral infarction in rats, by Y.-X. Xie, M. Zhang, C.-R. Zhang, F. Chen, published in Eur Rev Med Pharmacol Sci 2020; 24 (1): 295-303u2013DOI: 10.26355 eurrev_202001_19924u2013PMID: 31957843u201d has been retracted by the authors due to some inaccuracies. The authors state that they recently conducted animal experiments again to verify the state of apoptosis in the brain tissue of the CI + NogoA KO group. However, it was found that the phenomenon of apoptosis in the tissue was not significantly inhibited, and the same result was subsequently confirmed by RT-PCR. The Publisher apologizes for any inconvenience this may cause. , 
 *[left]* Fig 4 from  Dexmedetomidine Protects against Transient Global Cerebral Ischemia Reperfusion Induced Oxidative Stress and Inflammation in Diabetic Rats ([Zeng et al 2016] ). *[right]* **Fig 2**. ![file] , 
 #1 Fig 3 from [Wang et al 2019] , and the present Fig 5: ![] Pirated from Fig 2B of  Ursolic Acid Ameliorates Inflammation in Cerebral Ischemia and Reperfusion Injury Possibly via High Mobility Group Box 1 Toll-Like Receptor 4 NFu03baB Pathway ([Wang et al 2018] ). ![file] , 
 #2 Fig 6 from [Wang et al (2019)] , and the present Fig 7: ![] Pirated from Fig 6B of  Preventive Effect of Low Intensity Pulsed Ultrasound against Experimental Cerebral Ischemia Reperfusion Injury via Apoptosis Reduction and Brain-derived Neurotrophic Factor Induction ([Chen et al 2018] ). ![file] , 
 *[left]* Fig 6; and *[right]* the source, Fig 3A of  Dexmedetomidine Protects against Transient Global Cerebral Ischemia Reperfusion Induced Oxidative Stress and Inflammation in Diabetic Rats ([Zeng et al 2016] ). Flipped horizontally to facilitate comparison. ![file] #3  The article ... has been retracted by the authors due to **some inaccuracies** . ,