Figure 4. Oxidatively-modified LDLs induce nociception in Hargreaves assay.

Paw withdrawal latency <100 in the Hargreaves assay indicates increased pain related behaviour induced by the respective treatment. (A) Illustrates the % withdrawal latencies ± SEM (as compared to saline) following injection with known pain inducer carrageenan (3%) or PGE₂ (50ng/mL). Significant reductions in withdrawal latency were observed at 60, 180 and 240 minutes (min) post-carrageenan injection. Significant reductions in withdrawal latency were observed post-PGE₂ treatment at 30, 60, 120, and 180 minutes. (B) Illustrates the % withdrawal latencies ± SEM (as compared to saline) following injection with 100μg/ml L0, L1 or L2. Compared to saline, significant decreases in withdrawal latency were observed at 120min and 240min for L0 and L1 respectively and at 60, 240, 300 and 360min for L2. (C) Illustrates the % withdrawal latencies ± SEM (as compared to saline) following injection with 100μl PF (+) Endo or PF (-) Endo. Relative to saline, significant reductions in withdrawal latency were observed at 30, 240 min and 300 min following treatment with PF (+) Endo and at 240min following treatment with PF (-) Endo. Abbrev: PGE₂: Prostaglandin E2; L0: Native LDL; L1: Minimally modified LDL; L2: oxidized LDL. PF (+) Endo: Peritoneal fluid from women with endometriosis; PF (-) Endo: Peritoneal fluid from control subjects; *: <0.05; **: <0.01; ***: <0.005. Arrows and labelled treatments above the arrow represent points of significant induction of pain related behaviour by the stated treatment at the respective time points. The line presented at 100% indicates no change in response between treatment and saline. Statistical significance was determined using linear mixed effects models (LME) as described in the methods section.