Table 2

Categories for data extraction

CategoryCategory options
1Type of studyIn silico, in vitro, in vivo
2SpeciesFor example, human, rabbit, rat, mouse
3Direct measurement of painYes or no; if so, which method was undertaken? Options: pain behaviour in animals, patient’s pain assessed in clinical practice, Visual Analogue Scale, Numerical Rating Scale or sensory testing
4Direct interaction*Yes or no; if not, which cells or molecules were investigated? Options: neurons, fibroblasts or cytokines. How was the direct interaction measured? Options: in the same experiment, in same paper or only mentioned in the text, but not explored experimentally
5Experimental techniqueFor example, histological staining, western blot, quantitative PCR, PCR, ELISA, bulk RNA-seq, FACS, electrophysiology, animal behaviour, Ca2+ imaging
6Mention of blindingYes or no
7Mention of randomisationYes or no
8Mention of power calculationsYes or no
9n numbersn number used per group
10P valuesP value for individual experiment
11Quality score†0–3 (0, not qualified to judge; 1, low; 2, average; 3, high)
12DisorderFor example, rheumatoid arthritis, osteoarthritis, tendinopathy
13Type of interventionFor example, which model was used? was there an experimental manipulation, for example, antitumour necrosis factor?
14NoteShort summary of experimental result
  • *Direct interaction means that both fibroblasts and neurons/pain were assessed, detected or measured in a single experimental output, for example, if the both neurons and fibroblasts were counted in the same tissue sections. Cases in which one cell type was manipulated and the other one was evaluated were also considered to be direct interactions.

  • †In addition to the objective quality scores recorded as items 6 to 10, we assigned a subjective quality score based on our experience of a particular experimental technique, assessing for instance, the quality of an image, extreme variability in the data pointing towards a possible lack of power, or lack of controls.