Post-operative pain in mice is prolonged by diet-induced obesity and rescued by dietary intervention

Diet, body weight and pain susceptibility – A systematic review of preclinical studies

“…This was the case in all selected studies with animals presenting allodynia and hyperalgesia as well as increased nocifensive behaviors ( Guillemot-Legris et al, 2018 , Iannitti et al, 2012 , Song et al, 2018 ) however, the effects were prolonged over time in HFD models ( Guillemot-Legris et al, 2018 , Song et al, 2018 ) but not in genetic models ( Iannitti et al, 2012 ); in both HDF studies, diet switch improved pain-related outcomes. Diet impact was particularly evident in male rats ( Song et al, 2018 ).…”

“… Study Species Strain/subtrain Sex Age 1 N 2 Pain model 3 ( Bonomo et al, 2020 ) Mice C57BL/6J M 7/21 12–14 acute ( Bonomo et al, 2020 ) Mice C57BL/6J M 6/16 40 subacute ( Choucair-Jaafar et al, 2014 ) Mice C57BL/6J M g.m./7 30 acute ( Cooper et al, 2018 ) Mice C57BL/6J, C57BL/6NIH and C57BL/6CR M 8/15 60 acute; subacute ( Cristino et al, 2016 ) Mice C57BL/6J M g.m. ; 9–11 (HFD)/16–18 – acute; chronic ( Croci and Zarini, 2007 ) Rat SD Crl:CD F 4/40 15–36 acute; chronic ( Davidson et al, 2014 ) Rat SD M 12/28 20–24 acute ( Gavini et al, 2018 ) Mice C57BL/6J M wn/wn + 12 16 acute ( Guilford et al, 2011 ) Mice C57BL/6 M 7/16 30–42 acute ( Guillemot-Legris et al, 2018 ) Mice C57BL/6J M …”

“…capsaicin ( Iannitti et al, 2012 , Rossi et al, 2016 , Rossi et al, 2019 ), formalin ( Cooper et al, 2018 , Hu et al, 2018 ) or carrageenan ( Iannitti et al, 2012 , Wang et al, 2014b ) – or a lesion – e.g. paw incision ( Guillemot-Legris et al, 2018 , Iannitti et al, 2012 , Song et al, 2018 ). In the specific case of neuropathy models, most commonly lesions in the peripheral nervous system were used to model neuropathic pain like in the spared nerve injury (SNI; Decosterd and Woolf, 2000 ) model –( Cristino et al, 2016 , Guo et al, 2019 ) – but 1 model of perineural inflammation was also used ( Song et al, 2017 ).…”

“… HFD presented a more intense and prolonged response to carrageenan with decreased thresholds/latencies; ( Wang et al, 2014b ) Formalin Nocifensive behaviors HFD Increased body weight at HFD w 3. C57BL/6CR presented the greatest difference to controls at HFD w 8; HFD C57BL/6CR displayed increased nocifensive behaviors in the acute phase of the formalin test; no alterations were observed in tonic phase in all strains; ( Cooper et al, 2018 ) Formalin Nocifensive behaviors HFD; ob/ob ; db/db HFD gained significantly more body weight and fat than the control group; HFD presented reduced nocifensive behavior (paw flinches) in both acute and tonic phases of the test (diet switch for 3 ws rescued the phenotype); similar results for the ob/ob and db/db models; ( Hu et al, 2018 ) PGE2 Mechanical allodynia (VF) HFD; voluntary physical activity Significantly higher body mass in HFD; PGE decreased thresholds (increased delta); this effect was sustained in HFD but not controls; voluntary physical activity counteracted this effect however physical activity was significantly higher in controls; ( Brandao et al, 2019 ) Postoperative pain Hindpaw incision Mechanical allodynia (VF) HFD HFD-fed mice (60 day protocol) developed an obese phenotype characterized by increased body weight and fat depots; Thresholds decreased after incision in both HFD and controls recovering in the latter after 14 days; allodynia lasted at least 162 days in HFD however diet switch rescued post-operative pain; ( Guillemot-Legris et al, 2018 ) Hindpaw incision dynamic plantar aesthesiometer; Hargreaves fa/fa fa/fa presented significantly increased weight compared to fa/ - (14 ws); Both obese ( fa/fa ) and lean ( fa/ -) rats presented decreased mechanical thresholds and thermal hyperalgesia; no differences were observed between the 2 groups; ( Iannitti et al, 2012 ) Hindpaw incision Mechanical allodynia (VF); nocifensive behaviors HFD There was...…”

High-fat diet and post-operative pain: Why the hospital cafeteria may matter

“…The new study by Guillemot-Legris et al (Guillemot-Legris et al, 2018) is an interesting addition to this field. They examined the effects of a high-fat diet on a postoperative pain model in mice.…”