ABSTRACT
Background: Since the treatments of long tracheal lesions are associated with some limitations, tissue engineered trachea is considered as an alternative option. This study aimed at preparing a composite scaffold, based on natural and synthetic materials for tracheal tissue engineering
Methods: Nine chitosan silk-based scaffolds were fabricated using three freezing rates [0.5, 1, and 2[degree]C/min] and glutaraldehyde [GA] concentrations [0, 0.4, and 0.8 wt%]. Samples were characterized, and scaffolds having mechanical properties compatible with those of human trachea and proper biodegradability were selected for chondrocyte cell seeding and subsequent biological assessments
Results: The pore sizes were highly influenced by the freezing rate and varied from 135.3x372.1 to 37.8x83.4 micro m. Swelling and biodegradability behaviors were more affected by GA rather than freezing rate. Tensile strength raised from 120 kPa to 350 kPa by an increment of freezing rate and GA concentration. In addition, marked stiffening was demonstrated by increasing elastic modulus from 1.5 MPa to 12.2 MPa. Samples having 1 and 2[degree]C/min of freezing rate and 0.8 wt% GA concentration made a non-toxic, porous structure with tensile strength and elastic modulus in the range of human trachea, facilitating the chondrocyte proliferation. The results of 21-day cell culture indicated that glycosaminoglycans content was significantly higher for the rate of 2[degree]C/min [12.04 micro g/min] rather than the other [9.6 micro g/min]
Conclusion: A homogenous porous structure was created by freeze drying. This allows the fabrication of a chitosan silk scaffold cross-linked by GA for cartilage tissue regeneration with application in tracheal regeneration
Subject(s)
Trachea , Tissue Scaffolds , Tissue Engineering , Freezing , RegenerationABSTRACT
Recurrent pregnancy loss [RPL] has been defined as two or more miscarriages before 20[th] week of gestation. It seems that IL-27 may reduce inflammatory responses and affect the survival of the embryo during human pregnancy. IL-27 polymorphisms may influence RPL by altering the levels or the activity of gene product. We studied for the first time the association of IL-27 -964 A>G single nucleotide polymorphism [SNP] with RPL in Iranian women. A case-controlled study was performed on two groups consisting of 150 healthy women with at least one delivery [control group] and 150 women with two or more primary RPLs history [RPL group]. The -964 A>G SNP in IL-27 gene was determined by PCR-RFLP technique. Genotype and allele frequencies were compared using Chi[2] tests between two groups. There was no difference between the two groups regarding age of women [29 +/- 4.4 [control] vs. 30.84 +/- 5.2 years [case]]. In the RPL group, the genotype frequencies of -964 A>G polymorphism were AG [49.3%], AA [40%], and GG [10.7%], and in the control group, they were AG [43.3%], AA [48.7%], and GG [8%]. There was no significant difference between the genotypes of AA, AG, and GG in two groups [p=0.23]. As the frequency of allele A was 64.7% in the RPL group and 70.3% in the control group, the difference in frequency of allele A in -964 A>G between two groups was not significant [p=0.19]. Our findings indicate that SNP of -964 A>G in IL-27 gene is not a risk factor for RPL in Iranian women