BACKGROUND: Sericulture plays an eminent role in development of rural economy in India. Silk filature is a unit where silk is unwound from the cocoons and the strands are collected into skeins. During the process workers are exposed to the high molecular weight proteins like Sericin and Fibroin which are potent allergens leading to sensitization over a period of time and subsequently occupational related health disorders. OBJECTIVE: To identify and compare the magnitude of silk allergen sensitization in workers of silk filatures. METHODS: A community based comparative descriptive study was conducted for a period of 1 year at Ramanagara in south India. One hundred twenty subjects working in the silk filatures formed the study group. For comparison, 2 types of controls were selected viz.120 subjects who were not working in the silk filatures but resided in the same geographical area (control A) and 360 subjects who were not working in silk filatures as well not residing in the same geographical area (control B). Skin prick test was used to identify the silk allergen sensitization. RESULTS: Mean age was 34.14 ± 2.84 years in the study group. Mean age was 40.59 ± 14.40 years and 38.54 ± 12.20 years in control A and control B, respectively. There were 35 males (29.16%) and 85 females (70.84%) in the study group. There were 58 (48.34%) males and 62 (51.66%) females and 152 (42.2%) males and 208 females (57.8%) in control A and control B, respectively. Sensitization to silk allergen was 35.83% in the study group and 20.83% in the control group A and 11.11% in control group B. There was difference in the allergen sensitivity between the study group and control groups and it was statistically significant (chi-square = 38.08; p < 0.001). CONCLUSION: There is high burden of silk allergen sensitization among silk filature workers.
Allergens ; Female ; Fibroins ; Humans ; India ; Male ; Molecular Weight ; Sericins ; Silk ; Skin ; Skin Tests

Dimethyl sulfoxide (Me SO) supplemented with fetal bovine serum (FBS) is a widely used cryoprotectant combination. However, high concentration of Me SO is toxic to cells, and FBS presents problems related to diseases such as bovine spongiform encephalopathy and viral infections. Silk protein is a kind of natural macromolecule fiber protein with good biocompatibility and hydrophilicity. The aim of this paper is to analyze the cryoprotective mechanism of silk protein as cryoprotectant. Firstly, differential scanning calorimetry (DSC) was used to measure the thermal hysteresis activity (THA) of silk protein. The THA of 10 mg/mL sericin protein was 0.96°C, and the THA of 10% (V/V) fibroin protein was 1.15°C. Then the ice recrystallization inhibition (IRI) of silk protein-PBS solution was observed with cryomicroscope. The cold stage was set at - 7°C, after 40 minutes' incubation, the mean grain size rate (MGSR) of sericin protein and fibroin protein were 28.99% and 3.18%, respectively, which were calculated relative to phosphate buffer saline (PBS) control. It is indicated that sericin and silk fibroin have certain effects of inhibiting recrystallization of ice crystals. Finally, the structure and physicochemical properties of silk protein were analyzed by Fourier transform infrared spectroscopy (FTIR). The results showed that the content of the random coil was 75.62% and the β-sheet structure was 24.38% in the secondary of sericin protein. The content of the β-sheet structure was 56.68%, followed by random coil structure 22.38%, and α-helix 16.84% in the secondary of fibroin protein. The above analysis demonstrates the feasibility of silk fibroin as a cryoprotectant, and provides a new idea for the selection of cryoprotectants in the future.
Animals ; Bombyx ; Calorimetry, Differential Scanning ; Fibroins ; Sericins ; Silk ; Spectroscopy, Fourier Transform Infrared

In our previous studies, dietary supplements of silk protein, sericin, and fibroin, were beneficial for improving epidermal levels of ceramides, which are the major lipids for maintaining the epidermal barrier. In this study, we investigated the dietary effects of silk protein on epidermal levels of free sphingoid bases and their phosphates such as C18 sphingosine (So), C18 sphinganine (Sa), C18 sphingosine-1-phosphate (S1P), and C18 sphinganine-1-phosphate (Sa1P), which are either synthetic substrate or degradative metabolites of ceramides. Forty-five male NC/Nga mice, an animal model of atopic dermatitis (AD), were divided into three groups: group CA was an atopic control and fed a control diet, group S was fed a 1% sericin diet, and group F was fed a 1% fibroin diet. Fifteen male BALB/c mice served as group C (control group) and were fed the control diet. All mice were fed with diets and water ad libitum for 10 weeks. Sa in group CA was lower than that in group C, but So in group CA was similar to that in group C. So and Sa were higher in groups S and F than those in group CA; So level was even higher than that in group C, and Sa level was similar to that of group C. The So/Sa ratio in group CA, which is reported to increase in AD, was significantly higher than that of group C. The So/Sa ratio was lower in groups S and F than that in group CA, and decreased further in group F. However, S1P and Sa1P in groups S and F were similar to those in group CA. Taken together, we demonstrated that silk protein, sericin and fibroin dietary supplements, increased So and Sa levels, and decreased the So/Sa ratio.
Animals ; Ceramides ; Dermatitis, Atopic ; Diet ; Dietary Supplements ; Fibroins ; Humans ; Lysophospholipids ; Male ; Mice ; Models, Animal ; Phosphates ; Sericins ; Silk ; Sphingosine ; Water

OBJECTIVES: The silk patch is a thin transparent patch that is produced from silk fibroin. In this study, we investigated the treatment effects of the silk patch in patients with traumatic tympanic membrane perforation (TTMP). METHODS: The closure rate, otorrhea rate, and closure time in all patients and the closure time in successful patients were compared between the paper patch and silk patch groups. RESULTS: Demographic data (gender, site, age, traumatic duration, preoperative air-bone gap, and perforation size and location) were not significantly different between the two groups. The closure rate and otorrhea rate were not significantly different between the two groups. However, the closure time was different between the two groups (closure time of all patients, P=0.031; closure time of successful patients, P=0.037). CONCLUSION: The silk patch which has transparent, elastic, adhesive, and hyper-keratinizing properties results in a more efficient closure time than the paper patch in the treatment of TTMP patients. We therefore believe that the silk patch should be recommended for the treatment of acute tympanic membrane perforation.
Adhesives ; Ear, Middle ; Fibroins ; Humans ; Silk* ; Tympanic Membrane Perforation*

OBJECTIVE: This study aims to prepare oriented scaffolds derived from a cartilage extracellular matrix (CECM) and silk fibroin (SF) and use to investigate their physicochemical property in cartilage tissue engineering. METHODS: Oriented SF-CECM scaffolds were prepared from 6% mixed slurry (CECM：SF=1：1) through modified temperature gradient-guided thermal-induced phase separation, followed by freeze drying. The SF-CECM scaffolds were evaluated by scanning electron microscopy (SEM) and histological staining analyses and determination of porosity, water absorption, and compressive elastic modulus of the materials. RESULTS: The SEM image showed that the SF-CECM scaffolds contained homogeneous reticular porous structures in the cross-section and vertical tubular structures in the longitudinal sections. Histological staining showed that cells were completely removed, and the hybrid scaffolds retained proteogly can and collagen. The composition of the scaffold was similar to that of natural cartilage. The porosity, water absorption rate, and vertical compressive elastic modulus of the scaffolds were 95.733%±1.010%, 94.309%±1.302%, and (65.40±4.09) kPa, respectively. CONCLUSIONS The fabricated SF-CECM scaffolds exhibit satisfactory physicochemical and biomechanical properties and thus could be an ideal scaffold in cartilage tissue engineering.
Cartilage ; Extracellular Matrix ; Fibroins ; Porosity ; Silk ; Tissue Engineering ; Tissue Scaffolds

INTRODUCTION: This study evaluated the bone regenerative effect of silk fibroin mixed with platelet-rich fibrin (PRF) of a bone defect in rabbits. MATERIALS AND METHODS: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The silk fibroin mixed with PRF was grafted into the right parietal bone (experimental group). The left side (control group) was grafted only PRF. The animals were sacrificed at 4 weeks and 8 weeks. A micro-computerized tomography (microCT) of each specimen was taken. Subsequently, the specimens were decalcified and stained for histological analysis. RESULTS: The average value of plane film analysis was higher in the experimental group than in the control group at 4 weeks and 8weeks after surgery. However, the difference was not statistically significant.(P>0.05) The tissue mineral density (TMD) in the experimental group at 4 weeks after surgery was significantly higher than the control group.(P<0.05) CONCLUSION: Silk fibroin can be used as a scaffold of PRF for rabbit calvarial defect repair.
Animals ; Bone Regeneration ; Fibrin ; Fibroins ; Parietal Bone ; Rabbits ; Silk ; Skull ; Transplants

PURPOSE: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S (R)) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh (R) ) METHODS:44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. RESULTS: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. CONCLUSIONS: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.
Bone Regeneration ; Fibrin ; Fibroins ; Humans ; Lactic Acid ; Membranes ; Polyglycolic Acid ; Regeneration ; Silk

For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.
Cartilage* ; Cartilage, Articular ; Chondrocytes ; Extracellular Matrix ; Fibroins ; In Vitro Techniques ; Silk* ; Tensile Strength ; Tissue Engineering*

silk fibroin as a biomaterial template for bone formation when mixed with nano-hydoxyapatite in vivo.MATERIALS AND METHODS: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The electrospun silk fibroin was coated by nano-hydroxyapatite and grafted into the right parietal bone (experimental group). The left side (control group) did not receive a graft. The animals were sacrificed at 6 weeks and 12 weeks, humanly. The microcomputerized tomogram (microCT) was taken for each specimen. Subsequently, they were undergone decalcification and stained for the histological analysis.RESULTS: The average value of all measured variables was higher in the experimental group than in the control at 6 weeks after the operation. BMC in the experimental group at 6 weeks after operation was 48.94 +/- 19.25 and that in the control was 26.17 +/- 16.40 (P = 0.027). BMD in the experimental group at 6 weeks after operation was 324.59 +/- 165.24 and that in the control was 173.03 +/- 120.30 (P = 0.044). TMC in the experimental group at 6 weeks after operation was 19.50 +/- 6.00 and that in the control was 10.52 +/- 6.20 (P = 0.011). TMD in the experimental group at 6 weeks after operation was 508.88 +/- 297.57 and that in the control was 273.54 +/- 175.91 (P = 0.06). Gross image of both groups showed higher calcification area at 12 weeks than them in 6 weeks. The average value of microCT analysis was higher at 12 weeks than that in 6 weeks in both groups. BMC in the experimental group at 12 weeks after operation was 51.21 +/- 8.81 and that in the control was 33.47 +/- 11.13 (P = 0.010). BMD in the experimental group at 12 weeks after operation was 323.39 +/- 21.54 and that in the control was 197.75 +/- 76.23 (P = 0.012). TMC in the experimental group at 12 weeks after operation was 21.44 +/- 5.30 and that in the control was 13.31 +/- 4.17 (P = 0.008). TMD in the experimental group at 12 weeks after operation was 524.47 +/- 19.37 and that in the control was 299.60 +/- 136.20 (P = 0.016).CONCLUSION: The rabbit calvarial defect could be successfully repaired by electrospun silk nano-fiber combined with nano-hydroxyapatite.]]>
Animals ; Durapatite ; Fibroins ; Microcomputers ; Osteogenesis ; Parietal Bone ; Rabbits ; Silk ; Skull ; Transplants ; X-Ray Microtomography

silk fibroin was used in a bone defect model.METHODS: Twenty rabbits were used and 40 calvarial defects were formed. They were divided as 4 groups (unfilled control, silk only, silk+10microg/ml substance P; Sub10, and silk+100microg/ml substance P; Sub100). All animals were humanely sacrificed 4 or 8 weeks after grafting. The specimens were analyzed by micro-computerized tomography and histological analysis.RESULTS: When compared to the unfilled control to silk only group, there was significant difference in bone mineral density (BMD) and the attenuation coefficient (AC) at 4 weeks (P=0.037 and 0.038, respectively). When compared Sub10 group to Sub100 group, there was significant difference in BMD and AC at 8 weeks (P=0.004 for all). Residual graft amounts were 52.1+/-15.8%, 15.2+/-9.2% and 9.0+/-3.3% for silk only, Sub10, and Sub100 groups, respectively. When comparing the residual graft amount of silk only to sub10 or sub100, the differences were statistically significant (P<0.001).CONCLUSION: The silk fibroin scaffold showed higher BMD and AC than the unfilled control. The combination graft with substance P and silk fibroin scaffold showed a faster graft degradation than with a silk fibroin scaffold only.]]>
Animals ; Bone Density ; Fibroins ; Humans ; Mesenchymal Stromal Cells ; Neurotransmitter Agents ; Osteogenesis ; Rabbits ; Silk ; Substance P ; Transplants