Neuroprotective effects of celastrol on sciatic nerve transection model in male Wistar rats

Document Type : Original Article


1 College of Pharmacy, University of Al-Ameed, Karbala, Iraq

2 College of Nursing, University of Al-Ameed, Karbala, Iraq

3 Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran

4 Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran

5 Department of Biophysics, Faculty of Advanced Technologies, University of Mohaghegh Ardabili, Namin, Iran


Objective(s): Celastrol is an herbal compound with neuroprotective properties. Our research aimed to assess the neuroprotective properties of celastrol on sciatic nerve transection in rats.
Materials and Methods: The rats’ left sciatic nerve was cut and sutured directly. The animals were then given 1 or 2 mg/kg celastrol intraperitoneally for two weeks. The sensory and locomotor behaviors of the animals were then evaluated for 16 weeks. Immunohistochemistry, ELISA, and real-time PCR were also utilized to evaluate macrophage polarization, cytokine secretion, and neurotrophin expression in injured nerves. 
Results: Results showed that both doses of celastrol significantly accelerated nerve regeneration and improved sensorimotor functional recovery when compared with controls. Nevertheless, administration of 2 mg/kg of celastrol significantly outperforms treatment with a dose of 1 mg/kg. Celastrol treatment-induced M2 polarization in macrophages decreased proinflammatory cytokines at the injury site. It also increased the expression of BDNF mRNA.
Conclusion: These findings suggest that a two-week treatment with celastrol had neuroprotective effects in a rat sciatic nerve transection model, most likely by inducing macrophage M2 polarization and anti-inflammatory effects.


1.Scheib J, Höke A. Advances in peripheral nerve regeneration. Nature Reviews Neurology 2013; 9:668-676.
2.Abdolmaleki A, Zahri S, Bayrami A. Rosuvastatin enhanced functional recovery after sciatic nerve injury in the rat. European Journal of Pharmacology 2020; 882:173260.
3.Magaz A, Faroni A, Gough JE, Reid AJ, Li X, Blaker JJ. Bioactive silk‐based nerve guidance conduits for augmenting peripheral nerve repair. Advanced healthcare materials 2018; 7:1800308.
4.Endo T, Kadoya K, Suzuki T, Suzuki Y, Terkawi MA, Kawamura D, et al. Mature but not developing Schwann cells promote axon regeneration after peripheral nerve injury. npj Regenerative Medicine 2022; 7:1-11.
5.Zhang K, Jiang M, Fang Y. The drama of Wallerian degeneration: the cast, crew, and script. Annual review of genetics 2021; 55:93-113.
6.Bautista M, Krishnan A. Self-renewal of peripheral nerve resident macrophage: does it represent a unique activation status? Neural regeneration research 2022; 17:999.
7.Li J, Yao Y, Wang Y, Xu J, Zhao D, Liu M, et al. Modulation of the Crosstalk Between Schwann Cells and Macrophages for Nerve Regeneration: A Therapeutic Strategy Based on Multifunctional Tetrahedral Framework Nucleic Acids System. Advanced Materials 2022:2202513.
8.Chen P, Piao X, Bonaldo P. Role of macrophages in Wallerian degeneration and axonal regeneration after peripheral nerve injury. Acta neuropathologica 2015; 130:605-618.
9.Li Y, Kang S, Halawani D, Wang Y, Alves CJ, Ramakrishnan A, et al. Macrophages facilitate peripheral nerve regeneration by organizing regeneration tracks through Plexin-B2. Genes & Development 2022; 36:133-148.
10.Zigmond RE, Echevarria FD. Macrophage biology in the peripheral nervous system after injury. Progress in neurobiology 2019; 173:102-121.
11.Gaudet AD, Popovich PG, Ramer MS. Wallerian degeneration: gaining perspective on inflammatory events after peripheral nerve injury. Journal of neuroinflammation 2011; 8:1-13.
12.Stratton JA, Holmes A, Rosin NL, Sinha S, Vohra M, Burma NE, et al. Macrophages regulate Schwann cell maturation after nerve injury. Cell reports 2018; 24:2561-2572. e2566.
13.Govindappa PK, Elfar JC. Erythropoietin promotes M2 macrophage phagocytosis of Schwann cells in peripheral nerve injury. Cell death & disease 2022; 13:1-12.
14.Mokarram N, Merchant A, Mukhatyar V, Patel G, Bellamkonda RV. Effect of modulating macrophage phenotype on peripheral nerve repair. Biomaterials 2012; 33:8793-8801.
15.Julier Z, Park AJ, Briquez PS, Martino MM. Promoting tissue regeneration by modulating the immune system. Acta biomaterialia 2017; 53:13-28.
16.Pei T, Yan M, Kong Y, Fan H, Liu J, Cui M, et al. The genome of Tripterygium wilfordii and characterization of the celastrol biosynthesis pathway. Gigabyte 2021; 2021:1-32.
17.Zhu Y, Zhang X, Zhang Y, Lü S, Li C. Identification of Genes Involved in Celastrol Biosynthesis by Comparative Transcriptome Analysis in Tripterygium wilfordii. Phyton 2022; 91:279.
18.Jiang M, Liu X, Zhang D, Wang Y, Hu X, Xu F, et al. Celastrol treatment protects against acute ischemic stroke-induced brain injury by promoting an IL-33/ST2 axis-mediated microglia/macrophage M2 polarization. Journal of Neuroinflammation 2018; 15:1-12.
19.Luo D, Guo Y, Cheng Y, Zhao J, Wang Y, Rong J. Natural product celastrol suppressed macrophage M1 polarization against inflammation in diet-induced obese mice via regulating Nrf2/HO-1, MAP kinase and NF-κB pathways. Aging (Albany NY) 2017; 9:2069.
20.Wu M, Chen W, Yu X, Ding D, Zhang W, Hua H, et al. Celastrol aggravates LPS-induced inflammation and injuries of liver and kidney in mice. American Journal of Translational Research 2018; 10:2078.
21.Kyung H, Kwong JM, Bekerman V, Gu L, Yadegari D, Caprioli J, et al. Celastrol supports survival of retinal ganglion cells injured by optic nerve crush. Brain research 2015; 1609:21-30.
22.Chen M, Liu M, Luo Y, Cao J, Zeng F, Yang L, et al. Celastrol Protects against Cerebral Ischemia/Reperfusion Injury in Mice by Inhibiting Glycolysis through Targeting HIF-1α/PDK1 Axis. Oxidative Medicine and Cellular Longevity 2022; 2022.
23.Bernal J, Baldwin M, Gleason T, Kuhlman S, Moore G, Talcott M. Guidelines for rodent survival surgery. Journal of Investigative Surgery 2009; 22:445-451.
24.Mohammad-Bagher G, Arash A, Morteza B-R, Naser M-S, Ali M. Synergistic effects of acetyl-l-carnitine and adipose-derived stromal cells on improving regenerative capacity of acellular nerve allograft in sciatic nerve defect. Journal of Pharmacology and Experimental Therapeutics 2019; 368:490-502.
25.Yang L, Li Y, Ren J, Zhu C, Fu J, Lin D, et al. Celastrol attenuates inflammatory and neuropathic pain mediated by cannabinoid receptor type 2. International Journal of Molecular Sciences 2014; 15:13637-13648.
26.Kiaei M, Kipiani K, Petri S, Chen J, Calingasan NY, Beal MF. Celastrol blocks neuronal cell death and extends life in transgenic mouse model of amyotrophic lateral sclerosis. Neurodegenerative Diseases 2005; 2:246-254.
27.Bain J, Mackinnon S, Hunter D. Functional evaluation of complete sciatic, peroneal, and posterior tibial nerve lesions in the rat. Plastic and reconstructive surgery 1989; 83:129-138.
28.Sarikcioglu L, Demirel B, Utuk A. Walking track analysis: an assessment method for functional recovery after sciatic nerve injury in the rat. Folia morphologica 2009; 68:1-7.
29.Ferdowsi S, Abdolmaleki A, Asadi A, Zahri S. Glibenclamide promoted functional recovery following sciatic nerve injury in male Wistar rats. Fundamental & Clinical Pharmacology 2022.
30.Hargreaves K, Dubner R, Brown F, Flores C, Joris J. A new and sensitive method for measuring thermal nociception in cutaneous hyperalgesia. Pain 1988; 32:77-88.
31.Rupp A, Dornseifer U, Fischer A, Schmahl W, Rodenacker K, Jütting U, et al. Electrophysiologic assessment of sciatic nerve regeneration in the rat: surrounding limb muscles feature strongly in recordings from the gastrocnemius muscle. Journal of neuroscience methods 2007; 166:266-277.
32.Scipio FD, Raimondo S, Tos P, Geuna S. A simple protocol for paraffin‐embedded myelin sheath staining with osmium tetroxide for light microscope observation. Microscopy research and technique 2008; 71:497-502.
33.Varejão AS, Melo-Pinto P, Meek MF, Filipe VM, Bulas-Cruz J. Methods for the experimental functional assessment of rat sciatic nerve regeneration. Neurological research 2004; 26:186-194.
34.Azimpour M, Mahmoudi F, Abdolmaleki A, Bayrami A. Thyroxine Accelerates Functional Recovery in a Rat Model of Sciatic Nerve Crush. Turkish Neurosurgery 2022; 32.
35.Zhang X, Alwaal A, Lin G, Li H, Zaid UB, Wang G, et al. Urethral musculature and innervation in the female rat. Neurourology and urodynamics 2016; 35:382-389.
36.Soluki M, Mahmoudi F, Abdolmaleki A, Asadi A, Sabahi Namini A. Cerium oxide nanoparticles as a new neuroprotective agent to promote functional recovery in a rat model of sciatic nerve crush injury. British Journal of Neurosurgery 2020:1-6.
37.Clements IP, Kim Y-t, English AW, Lu X, Chung A, Bellamkonda RV. Thin-film enhanced nerve guidance channels for peripheral nerve repair. Biomaterials 2009; 30:3834-3846.
38.Maeda Y, Otsuka T, Takeda M, Okazaki T, Shimizu K, Kuwabara M, et al. Transplantation of rat cranial bone-derived mesenchymal stem cells promotes functional recovery in rats with spinal cord injury. Scientific reports 2021; 11:1-11.
39.Tirassa P, Manni L, Stenfors C, Lundeberg T, Aloe L. RT-PCR ELISA method for the analysis of neurotrophin mRNA expression in brain and peripheral tissues. Journal of biotechnology 2000; 84:259-272.
40.Elfving B, Plougmann PH, Wegener G. Detection of brain-derived neurotrophic factor (BDNF) in rat blood and brain preparations using ELISA: pitfalls and solutions. Journal of neuroscience methods 2010; 187:73-77.
41.Astry B, Venkatesha SH, Laurence A, Christensen-Quick A, Garzino-Demo A, Frieman MB, et al. Celastrol, a Chinese herbal compound, controls autoimmune inflammation by altering the balance of pathogenic and regulatory T cells in the target organ. Clinical immunology 2015; 157:228-238.
42.Zhang C, Zhao M, Wang B, Su Z, Guo B, Qin L, et al. The Nrf2-NLRP3-caspase-1 axis mediates the neuroprotective effects of Celastrol in Parkinson’s disease. Redox Biology 2021; 47:102134.
43.MacKinnon SE, Dellon A, O’brien J. Changes in nerve fiber numbers distal to a nerve repair in the rat sciatic nerve model. Muscle & Nerve: Official Journal of the American Association of Electrodiagnostic Medicine 1991; 14:1116-1122.
44.Bai X, Fu R-J, Zhang S, Yue S-J, Chen Y-Y, Xu D-Q, et al. Potential medicinal value of celastrol and its synthesized analogues for central nervous system diseases. Biomedicine & Pharmacotherapy 2021; 139:111551.
45.Yu H-C, Huang H-B, Huang Tseng H-Y, Lu M-C. Brain-Derived Neurotrophic Factor Suppressed Proinflammatory Cytokines Secretion and Enhanced MicroRNA (miR)-3168 Expression in Macrophages. International journal of molecular sciences 2022; 23:570.
46.Keefe KM, Sheikh IS, Smith GM. Targeting neurotrophins to specific populations of neurons: NGF, BDNF, and NT-3 and their relevance for treatment of spinal cord injury. International journal of molecular sciences 2017; 18:548.
47.Önger ME, Delibaş B, Türkmen AP, Erener E, Altunkaynak BZ, Kaplan S. The role of growth factors in nerve regeneration. Drug discoveries & therapeutics 2016; 10:285-291.
48.Li R, Li D-h, Zhang H-y, Wang J, Li X-k, Xiao J. Growth factors-based therapeutic strategies and their underlying signaling mechanisms for peripheral nerve regeneration. Acta Pharmacologica Sinica 2020; 41:1289-1300.
49.Shen ZL, Lassner F, Bader A, Becker M, Walter GF, Berger A. Cellular activity of resident macrophages during Wallerian degeneration. Microsurgery 2000; 20:255-261.
50.Büttner R, Schulz A, Reuter M, Akula AK, Mindos T, Carlstedt A, et al. Inflammaging impairs peripheral nerve maintenance and regeneration. Aging cell 2018; 17:e12833.
51.Kuo H-S, Tsai M-J, Huang M-C, Chiu C-W, Tsai C-Y, Lee M-J, et al. Acid fibroblast growth factor and peripheral nerve grafts regulate Th2 cytokine expression, macrophage activation, polyamine synthesis, and neurotrophin expression in transected rat spinal cords. Journal of Neuroscience 2011; 31:4137-4147.
52.Dai W, Wang X, Teng H, Li C, Wang B, Wang J. Celastrol inhibits microglial pyroptosis and attenuates inflammatory reaction in acute spinal cord injury rats. International Immunopharmacology 2019; 66:215-223.
53.Zhang B, Zhong Q, Chen X, Wu X, Sha R, Song G, et al. Neuroprotective effects of celastrol on transient global cerebral ischemia rats via regulating HMGB1/NF-κB signaling pathway. Frontiers in Neuroscience 2020:847.
54.Liu D-D, Luo P, Gu L, Zhang Q, Gao P, Zhu Y, et al. Celastrol exerts a neuroprotective effect by directly binding to HMGB1 protein in cerebral ischemia–reperfusion. Journal of Neuroinflammation 2021; 18:1-18.