Acknowledgements: we would like to thank neurosurgeons of the Department of Neurosurgery, Nekrasova MA, Babenkova VV, Isaeva AN, Smirnova VA, Glukhova DS, Gabechiya GV, Choriyeva DB, Kozheva AKh, for assistance in our research.

Author contribution: Novikova AV — literature analysis, clinical data acquisition and biomaterial collection, preanalytical phase of the study, data analysis and interpretation, preparation of figures and graphs; Pravdyuk NG — literature analysis, task definition, study design, data analysis and interpretation; Saklakova VS — literature analysis, analytic phase of laboratory testing, definition and statistical analysis of mRNA abundance in biomaterial, scheduling; Lolomadze EA — analysis of laboratory work, analysis of mRNA abundance in biomaterial; Feniksov VМ and Nikolaev DA — admission to clinical data acquisition, neurological examination of patients, discectomy, biomaterial collection; Davygora KS — literature analysis, analysis of laboratory work; Timofeev VT — study planning, preanalytical phase of the study, evaluation of the data obtained; Shostak NA — research management, study design, data interpretation, manuscript editing.

Compliance with ethical standards: the study was approved by the Ethics Committee of Pirogov Russian National Research Medical University (protocol № 181 dated January 28, 2019); the informed consent to blood testing and investigation of intervertebral disc was obtained from all participants.