RESUMO
Objective The aim of this study was to investigate the mechanism underlying pruritus by comparing the epidermal growth factor receptor inhibitor(EGFRI)-erlotinib mouse model with the substance P(SP)-induced pruritus mouse model. Methods Two randomized groups of mice were treated with erlotinib or SP to induce pruritus. Behavioral and skin manifestations were observed. Pathological images and neurokinin 1 receptor(NK-1R)expression of the skin were determined. Concentration of interleukin(IL)-31, IL-33, histamine, leukotriene B4, and SP was analyzed by enzyme-linked immunosorbent assay. Nitric oxide was analyzed by colorimetry. Results Transient pruritus induced by erlotinib appeared 2 to 5 days after treatment. In contrast, continuous pruritus was observed during the first hour, but was then gradually relieved. These two shared similar scratching behavior. Concentration of neurotransmitters showed similar trends in changes among the erlotinib group and SP group. Immunohistochemical expression was also consistent between the erlotinib group and SP group. Conclusions Erlotinib-associated pruritus is related to release of signaling factors through the SP/NK-1R signaling pathway.
RESUMO
The aims of this study were to investigate the utility of solid microneedle arrays (150 µm in length) in enhancing transdermal delivery of peptides and to examine the relationship between peptide permeation rates and D2O flux. Four model peptides were used (Gly-Gln-Pro-Arg [tetrapeptide-3, 456.6 Da], Val-Gly-Val-Ala-Pro-Gly [hexapeptide, 498.6 Da], AC-Glu-Glu-Met-Gln-Arg-Arg-NH2 [acetyl hexapeptide-3, 889 Da] and Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2 [oxytocin, 1007.2 Da]). The influence of microneedle pretreatment on skin permeation was evaluated using porcine ear skin with Franze diffusion cell. Peptide permeation across the skin was significantly enhanced by microneedle pretreatment, and permeation rates were dependent on peptide molecular weights. A positive correlation between D2O flux and acetyl hexapeptide-3 clearances suggests that convective solvent flow contributes to the enhanced transdermal peptide delivery. It is concluded that solid microneedle arrays are effective devices to enhance skin delivery of peptides.