Pinus koraiensis needles (PKN) and cones (PKC) have been shown to protect against
inflammation and pathogenic bacteria. We investigated the efficacies and action mechanisms of topical applications of
1,3-butylene glycol (BG) extracts and
oral administration of their water extracts on
atopic dermatitis (AD) symptoms. After exposing HaCaT cells and Nc/Nga mice dorsal skins to
2,4-dinitrochlorobenzene (
DNCB) to induce
atopic dermatitis models, they were topically applied BG (AD-control), 30% PKNX, or 30% PKCX to the skin lesions and fed water extracts (0.5%) in high-fat diets for 5 weeks. Normal-control mice had no
DNCB exposure. Serum
immunoglobulin E (
IgE),
IL-4, and TNF-α levels and gene expressions of TNF-α,
IL-4,
IL-6, and IFN-γ in the dorsal skin and HaCaT cells were measured. The AD-control mice elevated TNF-α and
IL-6 mRNA levels in HaCaT cells. Both extracts attenuated clinical AD symptoms in AD-induced Nc/Nga mice: PKNX improved
hemorrhage,
erythema, and lichenification of dorsal skin better than PKCX while both similarly alleviated
erythema,
edema, excoriation, and
itching behavior. PKCX reduced
IgE contents and increased
filaggrin mRNA expression better than PKNX, but PKNX reduced
lipid peroxides and
mRNA levels of TNF-α and
IL-4 in the dorsal skin. In the histological analysis of the dorsal skin, the administration of both extracts significantly decreased mast cell numbers, immune cell infiltration, gaps between the epidermis and dermis, and abnormal cell and nucleus shapes. In conclusion, both PKCX and PKNX treatment alleviated the
DNCB-induced clinical symptoms of AD by alleviating immune-related symptoms and
inflammation in partially different pathways. Therefore, PKNX and PKCX may be effective for AD
therapy. PRACTICAL APPLICATIONS:
Atopic dermatitis (AD) is related to an overly activated immune response, and it has steadily increased last 3 decades. However, no optimal sustainable treatments are available. Pinus koraiensis needles and cones extracts have been used for anti-inflammatory and antimicrobial treatment. The present study demonstrated that their intake and
topical administration onto the AD lesion alleviated clinical AD symptoms associated with reduced proinflammatory
cytokines, mast cell numbers, and immune cell infiltrates to maintain dermal structure with maintaining
filaggrin expression in AD-induced HaCaT cells and Nc/Nga mice. These results suggested that Pinus koraiensis needles and cones extracts can be developed and applied as beneficial
alternative therapies for AD.