title: Orally administered betaine reduces photodamage caused by UVB irradiation through the regulation of matrix metalloproteinase-9 activity in hairless mice.
abstract: Betaine is widely distributed in plants, microorganisms, in several types of food and in medical herbs, including Lycium chinense. The administration of 100 mg betaine/kg body weight/day is an effective strategy for preventing ultraviolet irradiation‑induced skin damage. The present study aimed to determine the preventive effects of betaine on ultraviolet B (UVB) irradiation‑induced skin damage in hairless mice. The mice were divided into three groups: Control (n=5), UVB‑treated vehicle (n=5) and UVB‑treated betaine (n=5) groups. The level of irradiation was progressively increased between 60 mJ/cm2 per exposure at week 1 (one minimal erythematous dose = 60 mJ/cm2) and 90 mJ/cm2 per exposure at week 7. The formation of wrinkles significantly increased following UVB exposure in the UVB‑treated vehicle group. However, treatment with betaine suppressed UVB‑induced wrinkle formation, as determined by the mean length, mean depth, number, epidermal thickness and collagen damage. Furthermore, oral administration of betaine also inhibited the UVB‑induced expression of mitogen‑activated protein kinase kinase (MEK), extracellular signal‑regulated kinase (ERK), and matrix metalloproteinase‑9 (MMP‑9). These findings suggested that betaine inhibits UVB‑induced skin damage by suppressing increased expression of MMP‑9 through the inhibition of MEK and ERK.
authors.affiliation: KM‑Based Herbal Drug Development Group, Korea Institute of Oriental Medicine, Daejeon 305‑811, Republic of Korea.
authors.forename: A-Rang
authors.initials: AR
authors.lastname: Im
authors.affiliation: KM‑Based Herbal Drug Development Group, Korea Institute of Oriental Medicine, Daejeon 305‑811, Republic of Korea.
authors.forename: Hee Jeong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Pharmaceutical Sciences, Daniel K Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA.
authors.forename: Ui Joung
authors.initials: UJ
authors.lastname: Youn
authors.affiliation: School of Medicine and Institute for Nuclear Science and Technology, Jeju National University, Jeju 690‑756, Republic of Korea.
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Hyun
authors.affiliation: KM‑Based Herbal Drug Development Group, Korea Institute of Oriental Medicine, Daejeon 305‑811, Republic of Korea.
authors.forename: Sungwook
authors.initials: S
authors.lastname: Chae
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001622:Betaine / Q000008:administration & dosage* / Q000494:pharmacology*; D003094:Collagen / Q000378:metabolism; D004817:Epidermis / Q000187:drug effects / Q000528:radiation effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008812:Mice, Hairless; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D020011:Protective Agents / Q000494:pharmacology; D015595:Skin Aging / Q000187:drug effects* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D020011:Protective Agents; D001622:Betaine; D003094:Collagen; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020780:Matrix Metalloproteinase 9