Study of the Antioxidative Effects of Bombyx mori Silk Sericin in Cultures of Murine Retinal Photoreceptor Cells

Abstract

The availability of natural substances able to fulfill the role of antioxidants in a physiologic environment is important for the development of therapies against diseases associated with excessive production of reactive oxygen species and ensuing oxidative stress. Antioxidant properties have been reported episodically for sericin, a proteinaceous constituent of the silk thread in the cocoons generated by the larvae of the Lepidoptera order. We investigated the sericin fractions isolated from the cocoons spun by the domesticated (Bombyx mori) silkworm. Three fractions were isolated and evaluated, including two peptidoid fractions, the crude sericin and the purified (dialyzed) sericin, and the non-peptidoid methanolic extract of the crude fraction. When subjected to Trolox equivalent antioxidant capacity (TEAC) assay, the extract showed much higher antioxidant capacity as compared to the crude or purified sericin fractions. The three fractions were also evaluated in cultures of murine retinal photoreceptor cells (661 W), a cell line that is highly susceptible to oxidants and is crucially involved in the retinopathies primarily caused by oxidative stress. The extract displayed a significant dose-dependent protective effect on the cultured cells exposed to hydrogen peroxide. In identical conditions, the crude sericin showed a certain level of antioxidative activity at a higher concentration, while the purified sericin did not show any activity. We concluded that the non-peptidoid components accompanying sericin were chiefly responsible for the previously reported antioxidant capacity associated with sericin fractions, a conclusion supported by the qualitative detection of flavonoids in the extract but not in the purified sericin fraction.

Expanding the boundaries of silk sericin biomaterials in biomedical applications

“…For biomaterial implant integration, some level of immune response can promote tissue regeneration and angiogenesis around the area of implantation. 155 Macrophages can be polarized to M1 or M2 phenotypes, with the former classified as classically activated and proinflammatory, and the latter classified as alternatively activated and anti-inflammatory. 156 The inclusion of SS in SF-SS electrospun films can increase both M1 and M2 polarization (protein and gene expression for relevant M1 and M2 markers: CCR7, CD206, MCP-1, VEGF, and others) and their secretion of cytokines (TNFα, IL-10) compared to control SF-only films in vitro .…”

Recent Developments of Silk-Based Scaffolds for Tissue Engineering and Regenerative Medicine Applications: A Special Focus on the Advancement of 3D Printing

“…Sericin, a protein resembling silk gum, is thought to cause some delayed hypersensitivity incidents of silk sutures in scarce circumstances [ 50 ]. Additional research using isolated sericin from silk and sericin-based biomaterials has not demonstrated that sericin is the cause of adverse effects [ 51 ]. To pinpoint the origin of any cytotoxic non-fibroin rudiments in silk and create an effective diagnostic method, thorough investigations are required.…”

Sericultural By-Products: The Potential for Alternative Therapy in Cancer Drug Design

“…Although SF is the main protein used in cancer research, various studies have disclosed sericin’s therapeutic effects, including its anti-inflammatory [ 162 , 163 ] and antioxidative [ 164 ] activities. Moreover, it has been reported that sericin exhibits a great impact in anticancer research due to its cytotoxic activity, and also, it has been used for nanocarrier formulations in anticancer therapy [ 165 ].…”