Anti-Aging Effects of Ferulic Acid Through Multiple Aging Models and the Involvement of Nrf2/HO-1 in Photoaged Skin

다국어 초록 (Multilingual Abstract)

Aging is a multifactorial biological process characterized by progressive physiological decline due to oxidative stress, chronic inflammation, metabolic dysregulation, and diminished regenerative capacity. As aging arises from the interaction between intrinsic molecular damage and external stressors, an integrated assessment across multiple biological systems is essential to understand its fundamental mechanisms.
Ferulic acid (FA), a plant-derived phenolic compound, is well known for its antioxidant and cytoprotective properties and has been proposed as a potential anti-aging agent. However, its systemic effects under physiological aging conditions have not yet been comprehensively evaluated. This paper investigated the anti-aging efficacy of FA using integrated experimental models of UVB-induced skin photoaging, P407-induced vascular aging, and natural aging in mice.
In Chapter Ⅰ, in the UVB-induced photoaging model, FA exhibited potent free radical scavenging activity and significantly suppressed inflammatory mediators, including COX-2, iNOS, NO, and PGE₂, in activated macrophages. In HDFs, FA promoted ECM homeostasis by increasing COL1A1 and decreasing MMP-1 expression. Furthermore, FA increased the expression of CerS3 and SPTLC2 indicating enhanced barrier lipid synthesis. UVB-induced aging-related β-galactosidase activity was significantly reduced by FA. FA also increased HO-1 expression and enhanced wound closure capacity and normalization of UVB-induced HO-1 and Nrf2 expression levels suggest regulation of the Nrf2/HO-1 signaling axis.
In Chapter Ⅱ, in the P407-induced vascular aging model, FA improved dyslipidemia by reducing total cholesterol and LDL and restoring HDL levels, and normalizing elevated serum ALT and AST levels. FA alleviated hepatic steatosis, reduced adipocyte hypertrophy, and mitigated P407-induced aortic wall thickening, demonstrating protective effects against lipid-induced vascular and metabolic damage.
In Chapter Ⅲ, in a natural aging model, FA reduced body weight. In aged animals, FA 50mg/kg improved serum triglyceride and HDL profiles while reducing hepatic lipid accumulation and adipocyte hypertrophy and attenuated age-related aortic wall hypertrophy in both age groups. Furthermore, FA increased blood testosterone levels in both groups and increased Leydig cell density in testicular tissue. FA was shown to balance androgen metabolism by suppressing SRD5A2 gene expression while maintaining relatively stable 5α-reductase activity except at 100 µg/mL.
In conclusion, this study demonstrates that FA is a potent natural compound with integrated anti-aging efficacy across skin, vascular, and systemic levels. These results suggest potential of FA as a multifunctional bioactive ingredient for use in anti-aging foods, cosmetics, and therapeutics, and as a promising candidate for managing hormone-related disorders.

목차 (Table of Contents)

• ABSTRACT ⅰ
• CONTENTS ⅲ
• LIST OF ABBREVIATIONS ⅵ
• LIST OF TABLES ⅷ
• LIST OF FIGURES ⅸ
• Background of Research
• Chapter : Ⅰ Anti-photoaging Effects of Ferulic Acid and the Nrf2/HO-1 Mechanism in Skin 1
• 1.1. Introduction (Chapter Ⅰ ) 2
• 1.2. Materials and Methods 8
• 1.2.1. Chemicals and cell culture conditions 8
• 1.2.2. Determination of in vitro antioxidant capacity 8
• 1.2.3. UVB induced skin photoaging model 10
• 1.2.4. Cell viability assay 10
• 1.2.5. Quantitative RT-PCR (qRT-PCR) analysis 11
• 1.2.6. Determination of nitric oxide (NO) and prostaglandin E2 (PGE2) secretion 12
• 1.2.7. Senescence-Associated β-galactosidase (SA-β-gal) staining 12
• 1.2.8. Wound closure (Scratch) migration assay 12
• 1.2.9. Western blot analysis 13
• 1.2.10. Statistical analysis 13
• 1.3. Results and Discussion 14
• 1.3.1. Antioxidant activity of FA 14
• 1.3.2. Anti-inflammatory effects in RAW264.7 cells 17
• 1.3.3. Anti-aging effects in HDF cells 21
• 1.3.4. Protection against UVB induced photoaging 28
• 1.3.5. Mechanistic role of the Nrf2/HO-1 pathway in wound closure 33
• 1.4. Summary 42
• Chapter Ⅱ: Anti-aging Effects of Ferulic Acid in Vascular Aging 45
• 2.1. Introduction (Chapter Ⅱ) 46
• 2.2. Materials and Methods 50
• 2.2.1. Animal model and ethical approval 50
• 2.2.2. Experimental design 50
• 2.2.3. Poloxamer 407 (P407) induced vascular aging 52
• 2.2.4. Measurement of serum lipid profiles and body/organ weights 52
• 2.2.5. ALT/AST liver enzyme measurements 53
• 2.2.6. Histological analysis of liver, adipose, arteries tissues 53
• 2.2.7. Statistical analysis 54
• 2.3. Results and Discussion 55
• 2.3.1. Changes in body weight 55
• 2.3.2. Organ weight changes 57
• 2.3.3. Serum lipid profiles 60
• 2.3.4. Liver function markers 63
• 2.3.5. Histopathological analysis of hepatic and adipose tissues 66
• 2.3.6. Histopathological analysis of aortic tissue 70
• 2.4. Summary 72
• Chapter Ⅲ: Anti-aging Effects of Ferulic Acid in Natural and Systemic Aging 75
• 3.1. Introduction (Chapter Ⅲ) 76
• 3.2. Materials and Methods 82
• 3.2.1. Animal model and ethical approval 82
• 3.2.2. Experimental design 82
• 3.2.3. Tissue and serum collection and body/organ weights 84
• 3.2.4. Histological analysis of liver, adipose, arterial, and testicular tissues 84
• 3.2.5. Cell line and cell culture conditions 85
• 3.2.6. Cell viability assay 85
• 3.2.7. Differentiation of 3T3-L1 preadipocytes 85
• 3.2.8. Oil Red O staining 86
• 3.2.9. Quantitative RT-PCR (qRT-PCR) analysis 86
• 3.2.10. 5Reductase activity assayα 87
• 3.2.11. Statistical analysis 88
• 3.3. Results and Discussion 89
• 3.3.1. Body weight changes 89
• 3.3.2. Organ weight changes 92
• 3.3.3. Serum lipid profiles 95
• 3.3.4. Liver function markers 98
• 3.3.5. Histopathological analysis of hepatic and adipose tissues 101
• 3.3.6. Anti-adipogenic effects 107
• 3.3.7. Histopathological analysis of aortic tissue 111
• 3.3.8. Testosterone and leydig cell activity 114
• 3.3.9. SRD5A2 expression and 5α-Reductase activity 121
• 3.4. Summary 125
• General Discussion and Conclusion 129
• References 133