Assay of Contact Photosensitivity to Musk Ambrette in Guinea Pigs

Abstract

This study reports the induction of contact photodermatitis to musk ambrette, 2-methoxy-3,5-dinitro-4-methyl-t-butylbenzene, in guinea pigs. Photoallergic contact dermatitis was assayed using 2 alternative induction methods. Successful photosensitization was achieved only when the nuchal skin was stripped with scotch tape before application of musk ambrette and ultraviolet radiation. Induction methods utilizing nonstripped nuchal skin which induce photosensitivity to potent photoallergens were ineffective for musk ambrette. Phtotoxicity tests to musk ambrette at concentrations between 1 and 50% and a dose of 10.2 joules/cm2 from "Black Light" fluorescent tubes were all negative. Under identical irradiation conditions, anthracene at 0.9% and 8-methoxypsoralen at 1% were consistently positive. The mechanism of photosensitivity to musk ambrette appears to be photoallergic rather than phototoxic. The requirement for skin abrasion to induce photosensitization parallels the clinical reports of photosensitivity to musk ambrette in man.

The sensitizing capacity of atranorin

“…The present animal studies were not optimal for the induction of photoallergy since the nuchal area was not irradiated during the induction phase. This is of paramount importance in all presently established methods for the induction of photosensitization (20,21). Further studies using recommended induction techniques are in progress.…”

“…This is in some way analogous to musk ambrette photosensitization. But this substance is a proven photoallergen (21). While reluctant to propose lichen sensitivity as the primary cause, since this group of patients often show multiple contact and photocontact allergies, it does seem that the presence oflichen sensitivity may not always be a coincident finding in patients with chronic photosensitivity.…”

Induction of Photoallergy in Guinea-Pigs by Injection of Photoallergen-Protein Conjugates

“…This is invariably true since most allergens and photoallergens have non-specific protein-bind ing properties like those of fentichlor; T4CS, which is a uniquely strong photoallergen in vivo [17][18][19], ap pears to be an exception to this rule.…”

Ultraviolet Radiation Effects on Immune Processes

“…Although the guinea pig has been used successfully as a model for such processes, the requirements for pretreatment of the skin by tapestripping [20] or U V B irradiation [57] during immunization limits severely the interpretability of results. Maguire and Kaidbey [35] recently described a murine model which will enable investigators to analyse immune mechanisms involved in photoallergic contact hypersensitivity.…”