Objective To prepare a spider silk protein bilayer small diameter vascular scaffold using electrospinning, and to observe the blood compatibility in vitro. Methods The Arg-Gly-Asp-recombinant spider silk protein (pNSR16), polycaprolactone (PCL), gelatin (Gt), and heparin (Hep) were blended. Spider silk protein bilayer small diameter vascular scaffold (experimental group) was prepared by electrospinning, with pNSR16 ∶ PCL ∶ Hep (5 ∶ 85 ∶ 10, W/W) hybrid electrospun solution as inner spinning solution and pNSR16 ∶ PCL ∶ Gt (5 ∶ 85 ∶ 10, W/W) hybrid electrospun solution as outer spinning solution, but pNSR16 ∶ PCL (5 ∶ 85, W/W) hybrid electrospun solution was used as inner spinning solution in control group. The scaffold structure of experimental group was observed under scanning electron microscope (SEM); and the hemolysis rate, recalcification clotting time, dynamic clotting time, platelet adhesion, and platelet activation in vitro were compared between 2 groups. Results SEM results showed that bilayer fibers of scaffold were quite different in experimental group; the diameter distribution of inner layer fibers was relatively uniform with small pores, however diameter difference of the outer layer fiber was relatively big with big pores. The contact angle, hemolysis rate, recalcification clotting time, and P-selectin expression of scaffold were (35 ± 3) ° , 1.2% ± 0.1%, (340 ± 11) s, and 0.412 ± 0.027 respectively in experimental group, and were (70 ± 4) ° , 1.9% ± 0.1%, (260 ± 16) s, and 0.678 ± 0.031 respectively in control group; significant difference were found in indexes between 2 groups (P lt; 0.05). With the extension of time, the curve of coagulation time in experimental group sloped downward slowly and had a long time; the blood clotting index values before 30 minutes were significantly higher than those in control group (P lt; 0.05). Platelet adhesion test showed that the scaffold surface almost had no platelet adhesion in experimental group. Conclusion The spider silk protein bilayer small diameter vascular scaffold could be prepared through electrospinning, and it has good blood compatibility in vitro.
Objective To explore the effects of 4-phenylbutyric acid (4-PBA) on idiopathic pulmonary fibrosis (IPF) using a murine model of bleomycin (BLM)-induced pulmonary fibrosis. Methods Pulmonary fibrosis was induced in C57BL/6 mice by intratracheal injection of BLM. A total of 120 mice were randomly allocated into three groups: BLM group, BLM+4-PBA group, and control group. Pathology of lung tissue was analyzed to evaluate the degree of pulmonary fibrosis, and the survival of the mice was noted. The expression levels of the endoplasmic reticulum stress markers, activating transcription factor 6 (ATF6) and C/EBP homologous protein (CHOP), were analyzed in lung tissues from mice. Results BLM induced significant collagen deposition in the lungs of the mice, which was alleviated by 4-PBA. 4-PBA also dramatically improved the pulmonary function and increased the survival rate in the BLM+4-PBA group compared with that in the BLM group. Both the mRNA and protein expression levels of ATF6 and CHOP were significantly reduced in mouse lung tissue after 2 weeks of 4-PBA treatment. Conclusions 4-PBA treatment could alleviate BLM-induced pulmonary fibrosis in mice via the attenuation of endoplasmic reticulum stress.