Chinese Journal of Dermatology ›› 2010, Vol. 43 ›› Issue (10): 709-712.

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A preliminary study on the expression and function of μ-opioid system in the epidermis of patients with atopic dermatitis

  

  • Received:2010-04-01 Revised:2010-04-13 Online:2010-10-15 Published:2010-10-09

Abstract:

Objective To investigate the expression of μ-opioid system in the epidermis of patients with atopic dermatitis and its role in the pathogenesis of atopic dermatitis. Methods Thirty-two mice were equally divided into 4 groups, negative control group, pre-treatment group, naloxone group, and physiological saline group. Ovalbumin was used to sensitize mice in pretreatment group, naloxone group, and physiological saline group for 7 weeks, then, mice in naloxone group and physiological saline group were treated with intracutaneous naloxone or physiological saline solution for 1 week, respectively. Mice were killed in negative control group and pre-treatment group at the end of sensitization, and in naloxone group and physiological saline group after 1-week injection with naloxone or physiological saline, skin tissues were obtained from the back of killed mice and subjected to histological examination with HE staining and quantitative fluorescent PCR for the detection of mRNA expression of μ-opioid receptor (MOR) and its ligand (β-endorphin) in epidermis. The atopic dermatitis severity index of lesions and histological changes were assessed before and after the treatment. Results In comparison with the negative control mice, the epidermal expression level of MOR was significantly decreased (t = 2.549, P < 0.05) in pre-treatment group, but increased in naloxone group and showed no statistical difference from the negative control group (t = 0.671, P > 0.05). No significant difference was observed in the epidermal β-endorphin mRNA expression between negative control group and pre-treatment group or naloxone group (both P > 0.05). The improvement of lesions could be visualized after treatment with naloxone (t = 8.338, P < 0.01), which was concordant with the histological changes in naloxone group. Conclusions As an antagonist of MOR, naloxone can restore the expression of epidermal MOR in mice model for atopic dermatitis, and shows a certain efficacy in the treatment of atopic dermatitis, which proves that μ-opioid system is somewhat associated with the pathogenesis of atopic dermatitis.

Key words: atopic dermatitis, μ-opiate system, naloxone