Study on the intervention effect and mechanism of bacillus Calmette-Guerin polysaccharide and nucleic acid injection on atopic dermatitis by targeting the transient receptor potential vanilloid subtype 1 pathway

BACKGROUND: This study aimed to explore the mechanism of Bacillus Calmette-Guerin polysaccharide and nucleic acid injection (BCG-PSN) targeting the transient receptor potential vanilloid subtype 1 (TRPV1) pathway for atopic dermatitis (AD) in mice. METHODS: Experiment 1: a total of 30 Kunming (KM) mice were randomized into blank control, model, BCG-PSN low-dose (25 g/kg), BCG-PSN medium-dose (75 g/kg), BCG-PSN high-dose (225 g/kg), and positive drug (hydrocortisone 25 mg/kg) control groups. The AD model mice were established by induction with 2,4-Dinitrochlorobenzene (DNCB). After treatment in groups, the symptom score and scratching frequency in skin lesions were observed. The levels of immunoglobulin E (IgE), interleukin (IL)-4, IL-31, and IL-13 in serum were detected, as well as the levels of tumor necrosis factor-α (TNF-α), TRPV1, and nuclear factor (NF)-κB p65 in skin lesions in each group. Experiment 2: the optimal dose of BCG-PSN in Experiment 1 was adopted. A total of 20 KM mice were randomized into blank control, model, BCG-PSN, and BCG-PSN + PAC (PAC-14028) groups. The symptom score and scratching frequency in skin lesions were observed. The levels of IgE, IL-4, IL-31, and IL-13 in serum were detected, as well as the levels of TNF-α and TRPV1 in skin lesions in each group. RESULTS: In Experiment 1, compared with the blank control group, the ear tissues of mice in model groups developed AD, with increased symptom score, scratching frequency, levels of IgE, IL-4, IL-31, and IL-13 in serum and levels of TNF-α, TRPV1, and NF-κB p65 in skin lesions. Compared with the model group, BCG-PSN low-dose, BCG-PSN medium-dose, BCG-PSN high-dose, and positive drug control groups had reduced AD symptoms, decreased symptom score, and decreased scratching frequency, with declined expression of each inflammatory substance, including the greatest decrease in the medium-dose group. In Experiment 2, after BCG-PSN was combined with PAC, the inflammation indexes decreased compared with those in the model group, and increased compared with those in the BCG-PSN group. CONCLUSIONS: Intramuscular BCG-PSN can target the TRPV1 pathway, inhibit inflammation, and improve the symptoms of AD mice.