Protective effects of the antioxidant extract collected from Styela clava tunics on UV radiation-induced skin aging in hairless mice

Abstract

Ultraviolet (UV) radiation is considered a primary cause of skin damage, which is characterized by deep wrinkles, roughness, laxity and pigmentation through oxidative stress and oxidative photodamage. To examine the therapeutic effects of ethanol extract of Styela clava tunics (EtSCT) on UV radiation-induced skin aging in hairless mice, alterations in skin phenotype, histological structures, inflammation, endoplasmic reticulum (ER) stress, oxidative conditions and toxicity were investigated during 13 weeks of UV irradiation and topical application of EtSCT. EtSCT showed high reducing power (3.1%), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (92.7%) and NO scavenging activity (15.6%) due to its high total flavonoids (15.3 mg/ml) and total phenolics (36.8 mg/ml). The topical application of EtSCT suppressed photoaging of the skin of UV-irradiated mice, and this was demonstrated by the inhibition of wrinkle formation, the suppression of the erythema index as well as the prevention of transepidermal water loss. Additionally, the epidermal thickness and adipocytes number were recovered to a similar level as that in the no radiation group in the UV + EtSCT‑treated groups compared with the UV + vehicle‑treated group, and the expression of collagen I increased. The attenuation of mitogen‑activated protein kinase and ER stress signaling pathways activated by reactive oxygen species was also detected in the UV + EtSCT‑treated group. Inflammatory responses including the infiltration of mast cells, CD31 expression and interleukin-6 secretion were significantly lower in the UV + EtSCT-treated groups. Moreover, the concentration of malondialdehyde was reduced and the activity of superoxide dismutase was effectively recovered in the UV + EtSCT-treated groups compared with that in the vehicle-treated groups. Liver and kidney toxicity factors were maintained at a constant level. These results suggest that EtSCT has the potential for use as therapeutic drug which protects against skin aging by regulating the skin morphology, histopathological structures, ER stress, inflammation and oxidative conditions.

Prospective, preclinical comparison of the performance between radiofrequency microneedling and microneedling alone in reversing photoaged skin

“…Skin aging can be induced by both time passage (intrinsic aging) and chronic exposure to external influences (extrinsic aging) . Among various factors affecting extrinsic aging, UV radiation is the best‐known cause of skin damage and results in skin laxity, pigmentation, and wrinkles .…”

Isolation and Characterization of Polysaccharides from the Ascidian Styela clava

“…The polysaccharides isolated from the tunic may have been responsible for the bioactivities previously observed in extracts of S. clava , such as UV protection [ 11 ], prevention of hepatic injury [ 12 ], and anti-inflammatory effects [ 13 ]. Further work would be required to test the biological activity of the individual polysaccharides found.…”

“…Besides nanocellulose, S. clava contains other valuable compounds responsible for a range of observed bioactivities. In mice, ethanolic extracts of S. clava tunics have been shown to protect the skin from UV radiation [ 11 ] and the liver from hepatic injury [ 12 ], and aqueous extracts have displayed anti-inflammatory effects [ 13 ]. Enzymatic hydrolysates from S. clava have produced anti-inflammatory effects in zebrafish [ 14 ], in vitro antioxidant activity and growth inhibition of several cancer cell lines [ 15 ], and antihypertensive effects in patients with type 2 diabetes and hypertension [ 16 ].…”

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“…Expression in UVB Irradiated Mice: This was achieved by Real time-Polymerase Chain Reaction (Real Time-PCR) 15,16 .…”