Pea Sprout Extract Promotes Hair Follicle Regeneration via Anagen Phase Prolongation and Dual Modulation of Oxidative and Inflammatory Signaling

Abstract

Hair loss is a prevalent condition that affects individuals across all ages and genders. Its causes are multifactorial, involving genetic predisposition, hormonal imbalances, aging, stress and air pollution factors. A previous randomized clinical trial, reveals that daily administration of 100mg of pea sprout extract (PSE) for 8 weeks significantly increased hair density in patients, however, the underlying mechanisms remained unclear. Therefore, this study aims to investigate the efficacy and underlying mechanisms of PSE in promoting hair growth. In vitro experiments were conducted using human dermal papilla cells (hDPCs) and RAW 264.7 macrophage cells alongside an in vivo study in a C57BL/6 mouse model. Our study demonstrates that PSE promotes hair growth by activating the Wnt/β-catenin signaling pathway, upregulating hair growth-promoting factors, including IGF-1 and FGF7, while downregulating growth inhibitory factors, including IL-1β and BMP4. This indicates that PSE effectively modulates the balance of growth factors by enhancing dermal papilla-associated signaling, thereby harmonizing the hair growth cycle. Furthermore, our results reveal that PSE exhibits anti-oxidant and anti-inflammatory properties, which may help protect hair follicles from oxidative stress and inflammatory damage, processes that can be influenced by environmental pollutants. Inflammation relief involves the use of anti-inflammatory agents to suppress pro inflammatory cytokines, thereby improving the microenvironment surrounding hair follicles and supporting hair growth. PSE is a promising natural ingredient, offering potential benefits in combating hair loss and promoting healthier hair growth by modulating key signaling pathways and providing protective effects. Its potential as a potential natural alopecia treatment warrants more research.

Keywords: Dermal papilla cells (DPCs); Pea sprouts extract; Wnt/β-catenin; anti-oxidation; hair loss.

Fig. 1. Pea sprout extract stimulates the hair growth-related gene expression.

Cellular and molecular responses of hDPCs after 24-h treatment with PSE and MNX. (A) Viability of the hDPCs was measured after treatments with MNX (1 μg/ml) and PSE (10 and 50 μg/ml) using the WST-8 assay. (B) Relative mRNA expression levels of β-catenin pathway–related genes including β-catenin, and VEGF were measured after treatments with MNX (1 μg/ml) and PSE (10, 50 μg/ml) using a qPCR. (C) Relative mRNA expression levels of hair growth–promoting factors including IGF-1 and FGF7 were treated with MNX (1 ug/ml) and PSE (10, 50 μg/ml) using a qPCR. (D) Relative mRNA expression levels of hair growth–inhibiting factors such as BMP4, and TGFβ2 were treated with MNX (1 ug/ml) and PSE (10, 50 μg/ml) using a qPCR. n = 3. The results are presented as the mean ± SD. Statistical analyses were performed using one-way ANOVA followed by Tukey’s post hoc test. *P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001 vs Control.

Fig. 2. Pea sprouts extract regulates oxidative stress and inflammatory responses.

(A) Relative mRNA expression levels of antioxidant enzymes including catalase and superoxide were measured using qPCR in hDPCs following 24-h treatment with H₂O₂ alone, or in combination with MNX (1 μg/ml) or PSE (10 and 50 μg/ml). (B) Relative mRNA expression levels of inflammatory cytokines including IL-6, and TNF-α were assessed using qPCR in RAW 264.7 cells following 24-h treatment with LPS alone, or in combination with MNX (1 μg/ml) or PSE (10, 50 μg/ml). n = 3. The results are presented as the mean ± SD. Statistical analyses were performed using one-way ANOVA followed by Tukey’s post hoc test. * P < 0.05; ** P < 0.01; ***P < 0.001; vs H₂O₂ or LPS.

Fig. 3. Pea sprout extract visually stimulates the hair growth of the C57bL/6 mice.

The vehicle, PSE (25, or 50 mpk), or MNX (1 mpk) were orally administrated 5 times per week for 14 days. (A) Experiment scheme. (B) Body weight changes in mice over 14 days. (C) Photographs of the dorsal skin of mice taken with a DSLR camera. At day 0, n = 6. At day 9 and 14, n = 5. (D) Skin score measured on day 9. (E) Hair growth area measured on day 14. The results are presented as the mean ± SD. Statistical analyses were performed using one-way ANOVA followed by Tukey’s post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001 vs vehicle.

Fig. 4. Pea sprout extract prolonged the anagen phase in C57BL/6 mice.

The vehicle, PSE (25, or 50 mpk), or MNX (1 mpk) were orally administrated 5 times per week for 14 days. (A) Representative H&E-stained images of longitudinal and transverse sections of dorsal skin collected on day 14. (B) Anagen/telogen ratio measured from H&E-stained longitudinal sections on day 14. (C) Hair follicle count measured from H&E-stained transverse sections on day 14. (D) IHC analysis of hair growth–related growth factors including IGF-1 and FGF7 in skin tissue on day 14. (E) IHC analysis of hair growth–inhibiting factors including BMP4 and TGF-β2 in skin tissue on day 14. (F) Expression of IGF-1 in mouse serum on day 14 using ELISA. n = 3, The results are presented as the mean ± SD. Statistical analyses were performed using one-way ANOVA followed by Tukey’s post hoc test. **P < 0.01, ***P < 0.001, ****P < 0.0001 vs vehicle.

Fig. 5. Pea sprout extract enhances the Wnt/β-catenin signaling pathway and exhibits anti-inflammation in mouse model.

The vehicle, PSE (25, or 50 mpk), or MNX (1 mpk) were orally administrated 5 times per week for 14 days. (A) Protein expression of Wnt/β-catenin pathway–related factors including Wnt3a, β-catenin, and GSK3β using western blotting. (B) Protein expression of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α using western blotting. n = 3, The results are presented as the mean ± SD. Statistical analyses were performed using one-way ANOVA followed by Tukey’s post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 vs vehicle.