Abstract: In this study, the protective effects of hawthorn pectin oligogalacturonide extract against oxidative damage and photoaging induced by ultraviolet B (UVB) in HaCaT cells were explored. HaCaT cells were cultured and divided into four groups, including control group, radiation (30 mJ/cm2) group, low-dose (5 μg/mL oligogalacturonide extract) with 30 mJ/cm2 radiation group, and high-dose (10 μg/mL oligogalacturonide extract) with 30 mJ/cm2 radiation group. Cell viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) method. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and lactate dehydrogenase (LDH) were detected using commercial kits, and the contents of malondialdehyde (MDA), hydroxyproline (Hyp) and reactive oxygen species (ROS) were also measured. The secretion levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and matrix metalloproteinase 1 (MMP-1) were evaluated using enzyme-linked immunosorbent assay. The results showed that the cell viability of HaCaT cells significantly decreased after UVB exposure. Low- and high-dose hawthrown pectin oligogalacturonide extract had a significant growth promoting effect on UVB-irradiated HaCaT cells (P < 0.05). In addition, the extract significantly increased the activities of SOD, GSH-Px, and CAT, decreased LDH activity, ROS level and MDA content, augmented hydroxyproline concentration, and reduced the secretion levels of MMP-1, TNF-α and IL-6 compared with the model group. The mRNA expression levels of MMP-1, TNF-α and IL-6 as determined by realtime polymerase chain reaction were in agreement with the production of MMP-1, TNF-α, and IL-6. Therefore, hawthrown pectin oligogalacturonide has a protective effect against UVB radiation-induced oxidative damage and photoaging in HaCaT cells.

Key words: pectin oligogalacturonide, ultraviolet B radiation, HaCaT cell, antioxidant, photoaging