Alpha-melanocyte-stimulating hormone plays an important role in the onset of pollinosis in a pollen allergy mouse model.

BACKGROUND

alpha-Melanocyte-stimulating hormone (alpha-MSH) is a neuropeptide that controls melanogenesis in pigmentary cells. In addition, its potent immunomodulatory activity has been recently described in cutaneous inflammatory disorders. However the mechanism of such pollen allergies remains to be elucidated. The purpose of this study was to investigate the role of alpha-MSH in a murine model of pollen allergy.

METHODS

Eight-week-old male BDF-1 mice were sensitized with Cry j I. After the last intranasal antigen, the number of sneezes was counted for 5 min. In addition, the serum levels of IgE and neuronal hormones were measured by ELISA. The expression of IgA, melanocortin receptor 1 (MC1R) and MC5R in the trachea were also observed by immunohistochemistry.

RESULTS

Both the concentration of alpha-MSH and adrenocorticotropin in plasma increase in pollen allergy model mice. Furthermore, MC5R increased in the trachea; however, MC1R did not increase in the trachea. In addition, the changes in sneezing and IgA expression in the pollen allergy model mice were suppressed by alpha-MSH antibody treatment, but they remained unchanged after MC1R antagonist (agouti) treatment.

CONCLUSIONS

These results indicate that sneezing due to pollen allergy is associated with an increased concentration of alpha-MSH and the expression of MC5R.