Behavioral and morphological study of itch and negative emotions in solar dermatitis model mice

RAO Qian; ZHU Yuanyuan; LIN Yiting; NI Qingrong; WU You; ZHANG Yiwen; LEI Jing; HUANG Jing

doi:10.13276/j.issn.2097-1656.2024.12.012

Abstract：Objective To construct a mouse model of solar dermatitis,detect itch and anxiety and depression-like behaviors in mice,and observe the activation of neurons in the medial prefrontal cortex(mPFC)and anterior cingulate cortex(ACC).Methods A mouse model of solar dermatitis was constructed by broad-band ultraviolet B irradiation.The pathological changes of the skin of the neck and back of mice were observed by HE staining.Itch behavior and anxiety and depression-like behavior were detected by scratch test,elevated plus maze test,open field test and tail suspension test.The activation of neurons in mPFC and ACC was observed using immunofluorescence staining.Results The results of HE staining showed that the skin tissue of mice in the control group showed normal morphological structure,while the back skin of mice in the model group showed obvious erythema and characteristic"sunburned cells"in the acanthocyte layer.Compared with the control group,the model group showed a significant increase in the scratching bouts(P＜0.01),a reduction in the exploration time in the central area in the open field test(P＜0.05)and in the exploration time in the open arm in the elevated plus maze test(P＜0.01),and an increase in the immobilization time in the tail suspension test(P＜0.05).Immunofluorescence staining revealed a significant increase in the number of FOS positive cells in mPFC and ACC in the model group(P＜0.01).Conclusion In this study,we successfully established itch model of solar dermatitis and observed anxiety and depression-like behaviors in the model mice.Some neurons in mPFC and ACC were activated in the model group.The study provides morphological evidence for the involvement of mPFC and ACC in solar dermatitis itch and its accompanying negative emotions.