Background & Aims
Dipyrone, a widely used analgesic prodrug, holds immense therapeutic promise for alleviating pain of inflammatory origin. Its effectiveness and safety ensure broad clinical usage. Within hepatic pathways, dipyrone hydrolysis yields 4-methylaminoantipyrine (4-MAA), subsequently demethylated into 4-aminoantipyrine (4-AA). We have recently demonstrated that its analgesic mechanism of action does not involve any anti-inflammatory action (Gonçalves dos Santos, 2020 a, b). Notably, the analgesic potential of 4-MAA hinges on the activation of cannabinoid receptor type-2 (CB2R). However, given the role of M2 macrophages in inflammation resolution, dipyrone’s putative immunomodulatory capacity and M2 macrophage polarization emerge. So, this study aims to investigate the modulation of inflammatory processes by higher doses of dipyrone.
Methods
We conducted experiments on male Wistar rats weighing 200-220g. Elisa assay verified the expression of the cytokines TNF-?, IL-1? and IL-10. Rat’s paw received a subcutaneous 1% carrageenan injection (50 ?L) before dipyrone (1 mg/paw in 50 ?L ). Cell migration was evaluated through intraperitoneal injection of 1% carrageenan (500 ?L ) before dipyrone. Cells were counted using an optical microscope under a 100 x objective with immersion oil. Macrophage cells for cultivation were derived from the tibia and femur. Cells were plated with macrophage colony-stimulating factor (MCSF). Cells were stimulated with LPS (10 ng/mL) and IFN-? (10 ng/mL) for 1 hour, followed by dipyrone treatment. The dynamic polarization analysis of M-0 to M-1 and M-2 cells were conducted through the examination of gene expression of CD64 – M0 lineage; iNOS – M1 lineage) and Arg-1 – M2 lineage (Cao et al., 2023) by RT-PCR technique. The results were analyzed using the t-test or analysis of variance (ANOVA) followed
Results
Our results indicate that local dipyrone administration attenuated approximately 50% of carrageenan-induced paw edema. Dipyrone enhanced 300% of the monocyte migration and reduced 60% of total leukocyte and 80% of neutrophil migration. However, dipyrone did not change the lymphocyte migration. Dipyrone also diminished 50% of the IL-1? and 40% of TNF-? release at the inflammatory site and increased 25% of IL-10. In the indirect analysis of the macrophage polarization, dipyrone decreased by 50% of the iNOS M1 macrophage lineage, increasing the proportion Arg-1 M2 / iNOS M1 by 300%.
Conclusions
This study suggests that dipyrone, in a more significant dose than one with an analgesic effect, promotes modulation of the inflammatory process by inducing macrophage polarization.
References
Goncalves Dos Santos G, Li R, Pui MEN, Paes Lemes JB, Vieira WF, Nagy I, Tambeli CH, Parada CA (2020). CB1 receptor-dependent desensitisation of TRPV1 channels contributes to the analgesic effect of dipyrone in sensitised primary sensory neurons. Br J Pharmacol 177(20):4615-4626.
Gonçalves Dos Santos G, Vieira WF, Vendramini PH, Bassani da Silva B, Fernandes Magalhães S, Tambeli CH, Parada CA. (2020) Dipyrone is locally hydrolyzed to 4-methylaminoantipyrine and its antihyperalgesic effect depends on CB2 and kappa-opioid receptors activation. Eur J Pharmacol 874:173005.
Cao L, Tan Q, Zhu R, Ye L, Shi G, Yuan Z. (2023) LncRNA MIR4435-2HG suppression regulates macrophage M1/M2 polarization and reduces intestinal inflammation in mice with ulcerative colitis. Cytokine 170:156338.
Presenting Author
Carlos A Parada
Poster Authors
Carlos A. Parada
DDs MD PhD
State University of Campinas (UNICAMP)
Lead Author
Topics
- Treatment/Management: Pharmacology: Novel Targets