Effects Of Sericin Research Articles

Publisher's note to the retraction of “The effects of sericin in recovering spermatogenesis and sexual hormone levels in diabetic rats”

Publisher's note to the retraction of “The effects of sericin in recovering spermatogenesis and sexual hormone levels in diabetic rats”

Effects of sericin on oxidative stress and PI3K/AKT/mTOR signal pathway in cryopreserved mice ovarian tissue

Ovarian tissue cryopreservation is an effective fertility protective strategy for preadolescent female cancer patients, whose tumor treatment cannot be delayed. In the present study, the effects of sericin, as an antioxidant, on mice ovarian tissue freezing and thawing were investigated. Mice ovarian tissues were cryopreserved and thawed in medium containing 0.5% or 1%sericin (w/v), and 0.1 mM melatonin. Then, the follicular morphology was observed. The levels of antioxidant enzymes were determined, including glutathione (GSH), glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT). Moreover, the levels of nitric oxide (NO), malondialdehyde (MDA) and lactate dehydrogenase (LDH) were also tested. Besides, apoptosis-related proteins Bcl-2 and Bax were determined. Our results showed that 1% sericin maintained follicular morphology, inhibited apoptosis, decreased MDA and NO levels, and boosted endogenous antioxidant enzyme levels, while had no significant effect on LDH levels. Furthermore, these effects may be related with the activation of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of Rapamycin (mTOR) signaling pathway, as demonstrated by increased PI3K, p-AKT and mTOR levels. These findings demonstrate that 1% sericin may reduce oxidative stress and protect ovarian tissues during freezing and thawing via PI3K/AKT/mTOR signaling pathway.

Effects of sericin and egg white on the inflammation of damaged skin in mice

Sericin and egg white (EW) have shown the ability to promote wound healing. However, there have been insufficient studies regarding the effects of sericin and EW mixtures on wound healing. This study aimed to investigate the effects of a hybrid sericin and EW solution on wound repair and inflammation-related indicators in mouse skin. In this work, sericin with a low molecular weight was first mixed with homogeneous EW to prepare a hybrid wound dressing. Histology evaluation, the expression of C-reactive protein (CRP) and inflammatory cytokines in mice were tested to determine the effects of this dressing on skin injuries in mice. The results showed that sericin and the hybrid solution of sericin and EW effectively promoted wound healing in mouse skin. The wound recovery rates of mice 12 days after treatment with a medium dose of sericin (0.2 g ml−1) and the same dosage of sericin with added EW were 1.32 and 1.65 times that of mice treated with phosphate buffer saline as a control, respectively. In addition, the mixture solution was more effective in wound healing than sericin alone. Sericin with EW significantly reduced the expression of CRP and inflammatory cytokines in mice during wound healing. A sericin and EW hybrid solution can effectively shorten the time needed for wound healing and reduce inflammation-related indicators in mice, making it a promising candidate for wound dressing.

Sericin eco-friendly biomaterial as a spin finish in drawn textured PET yarn production

PurposeThis paper aims to extracted sericin from the cocoons of Bombyx mori silkworms, and sericin powder was applied onto drawn textured polyethylene terephthalate (PET) yarns as a spin finish. The reactivity on the surface of PET yarns was analyzed through Fourier transform infrared spectrophotometry–attenuated total reflectance (FTIR-ATR) and dyeing with methylene blue as a reactive dye. Also, investigations were conducted on the effects of sericin, citrc acid (CA) (as a crosslinking agent), and sodium hypophosphite (as a catalyst) concentrations on some properties of false-twist textured PET yarns.Design/methodology/approachA false-twist texturing machine (Scragg-Shirley minibulk, England) was used with the draw ratio of 1.05, heating temperature of 120°C, texturing speed of 100 m min−1 and applied twist of 3,000 TPM. The aqueous extraction of sericin was carried out by the boiling of the raw silk in distilled water with L:R: 40:1 for 120 min. The aqueous solution was filtered with a filter paper to remove the impurities and insoluble fibroin. Finally, the sericin solution was freeze-dried to obtain the sericin powder. The sericin solution was applied on the drawn textured PET yarns using the “pad-dry-cure” method.FindingsSericin fixation onto the PET yarns was confirmed by FTIR-ATR. The results showed that there were no significant changes in the tensile strength, linear density, crimp contraction and crimp modulus, elongation at break and shrinkage. In contrast, a substantial increase was observed in moisture regain, vertical wicking, dye uptake and ultraviolet protection. There was also a reduction just in the electrical resistivity, in the presence of sericin.Originality/valueAlthough sericin has been known to have numerous beneficial properties, its application in textile industry as a spin finish has not been reported yet.

Inhibitory effects of intact silkworm sericin on bacterial proliferation

Sericins are derived from the outer layer of silk thread proteins of the common silkworm (Bombyx mori) and act as a glue to fix fibers of the developing cocoon. Although sericin has potential uses in various fields, including tissue engineering and the development of cosmetics, biological applications of intact sericin have yet to be identified. We previously developed transgenic silkworms that produce cocoons solely composed of sericin, from which we can readily prepare a solution of intact sericin. Here we report the effects of intact sericin on the proliferation of bacteria. The intact sericin does not kill bacteria, but colony size of Escherichia coli on culture media was reduced by up to 90% when cultured in the presence of intact sericin. In addition, treatment of intact sericin reduced colony size of Salmonella enterica, indicating a potential inhibitory effect of intact sericin on growth in Gram-negative bacteria. However, Gram-positive bacteria, including Staphylococcus aureus and Bacillus subtilis, were not affected by intact sericin. Thus, our results indicate that the cell wall structure of different bacteria may influence their sensitivity to the inhibitory effects of sericin.

RETRACTION NOTE TO: The effects of sericin in recovering spermatogenesis and sexual hormone levels in diabetic rats.

Sericin-S (a hydrolysate from the silk protein sericin) is a natural antioxidant, which may improve spermatogenesis while having high biological safety, thus potentially useful for the treatment of male infertility. Our objective was to determine the effects of sericin-S on the sperm parameters and sexual hormone levels in a diabetic rat model. Thirty-six adult male rats were randomly divided in two groups, inducing diabetes in one of them by intraperitoneal administration of streptozotocin (STZ; 65 mg/kg). Both groups were randomly assigned to three subgroups, receiving oral gavage of saline, 1% or 2% sericin extract for 60 days. Therefore, the experimental design was a 2 × 3 factorial design of STZ and sericin treatments. One day after the last treatment, the rats were euthanized, weighed, the testes were processed (weigh, volume, and histology), and serum samples were processed for measuring sex hormone levels [testosterone, follicle-stimulating hormone, and luteinizing hormone (LH)]. STZ treatment decreased LH concentration and counts of spermatogonia, spermatocytes, and spermatids. Body and testis weights were significantly (p < 0.05) lower in the control group (non-diabetic saline) compared to the treated groups. In non-diabetic rats, sericin treatments increased (p < 0.05) the number of testicular cells (spermatogonia, spermatocytes, spermatids, Sertoli, and Leydig cells) and sex hormone concentrations. In diabetic rats, administration of sericin significantly (p < 0.05) improved sperm cell number and sex hormones levels. In nutshell, sericin can clearly modify sperm parameters and overall sex hormone function, and could improve spermatogenesis in normal and diabetic rats.

The effects of sericin on cryopreserved sperm cells and subsequent embryo development in mice

Sericin, because of its ability to remove free radicals and its antioxidant properties, has been used to successfully cryopreserve various mammalian cell types. However, the effects of sericin on cryopreservation of mouse sperm has not been reported. The current study intended to determine the protective role of different concentrations of sericin (0, 0.25, 0.5, and 0.75%) on mouse spermatozoa during cryopreservation, in addition to its effect on in vitro fertilization and subsequent embryo development. Mouse sperm from epididymides were frozen in cryoprotective agent with 18% raffinose, 3% skim milk, and different concentrations of sericin (0, 0.25, 0.5, 0.75%). Thawed sperm were used for in vitro fertilization. The obtained embryos were cultured in Ksom medium for 6 days. The post-thawed motility, viability, fertilizing ability, and subsequent development to the 2-cell embryo and blastocyst stages were evaluated. Our findings show that frozen-thawed sperm cells with 5% sericin indicate significantly (p≤0.0001) percentages of survivability and motility, the best fertilizing ability, as well as 2-cell embryo and blastocyst development compared to the other treated groups. There was no significant difference in survivability (p=0.8781), fertilizing ability (p=0.2458) and development of 2-cell (p=0.5136) and blastocysts embryos (p=0.0896) between 0.75% sericin and control groups. Supplementation by 0.5% sericin in cryoprotective agent improved frozen-thawed mouse epididymal sperm cell quality and resulted in increased embryo development.

Protection of sericin to retinal microvessels and its mechanism in diabetic rats

Background Diabetic retinopathy (DR) is a chronic inflammatory disease, with pathological changes of retinal microvessels.Studies demonstrated that sericin has anti-inflammation and anti-oxidation effects, inferring that sericin might play a protective effect on diabetic microangiopathy. Objective This study was to investigate the effects of sericin on intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and Cx43 expressions in retina and explore the protection of sericin to retinal microangiopathy in diabetic rats. Methods Forty-eight specific pathogen free male SD rats were randomly divided into normal control group, diabetic model group, sericin-treated group and calcium dobesilate-treated group, with 12 rats for each group.The diabetic models were established by intraperitoneal injection of streptozotocin (STZ) for 3 consecutive days and feeding up with high lipid foods.Normal saline solution, 2.4 g/(kg·d) sericin solution and 0.2 g/(kg·d) calcium dobesilate were used by gavage administration in the rats of the diabetic model group, sericin-treated group and calcium dobesilate-treated for 3 months group, respectively.The rats were sacrificed and retinal sections were prepared, and the retinal morphology was examined by hematoxylin-eosin staining.The expressions of ICAM-1, VCAM-1 and Cx43 proteins and mRNA in retinas were detected by Western blot assay and reverse transcription PCR.The use and care of the rats complied with Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission and ARVO statement. Results The retinal structure was normal in the normal control group.The swell and rupture of inter limiting membrane (ILM), scatter vascular endothelial cell nuclei breakthrough ILM and decrease of retinal ganglion cells (RGCs) were displayed in the diabetic model group; while in the sericin-treated group and calcium dobesilate-treated group, the mild thickening of ILM and disorder of retinal cells were obtained.The relative expression levels of ICAM-1 and VCAM-1 were significantly raised and those of Cx43 were reduced in the diabetic model group, sericin-treated group and calcium dobesilate-treated group when compared with the normal control group (all at P<0.05). Compared with the diabetic model group, the expressions of ICAM-1 and VCAM-1 proteins and mRNA in the sericin-treated group were significantly reduced (ICAM-1 protein: 0.834 3±0.032 1 vs. 0.918 9±0.042 4; VCAM-1 protein: 0.726 4±0.011 2 vs. 1.235 0±0.078 9; ICAM-1 mRNA: 0.716 3±0.008 6 vs. 0.956 8±0.012 5; VCAM-1 mRNA: 0.393 7±0.035 0 vs.0.477 9±0.020 6) and those of Cx43 protein and mRNA were evidently elevated (Cx43 protein: 0.133 1±0.015 3 vs.0.039 2±0.002 0; Cx43 mRNA: 0.676 8±0.064 8 vs.0.430 8±0.111 3) (all at P<0.05). Conclusions Sericin can relieve retinal microangiopathy and protect retina against the pathogenesis and development of DR by down-regulating the expressions of ICAM-1, VCAM-1 and up-regulating the expression of Cx43 in retinas of diabetic rats. Key words: Sericins/pharmacology; Anti-inflammatory agents/pharmacology; Diabetic retinopathy/physiopathology; Gene expression; Intercellular adhesion molecule-1; Vascular cell adhesion molecule-1; Connexin 43; Retinal vessels/physiopathology; Rats, Sprague-Dawley