It is important to design a long-period transparent bioactive material for corneal repair in the process of corneal tissue renovation. This article discusses the silk fibroin and formamide blend membranes as a corneal stroma repair material. Silk fibroin solution was mixed with formamide in different proportions to obtain insoluble transparent silk fibroin film by casting method. The blending membranes had excellent mechanical properties, cell compatibility and long-term transparent properties. Rabbit corneal stromal cells were seeded on the sterilized composite films. The rate of cell surface adhesion was over 90% after cells were placed on it for 5 hours. When cells were seeded on blend membranes from one day to seven days, Alma Blue was added to complete medium. Compared with the cell culture plate, there was no significant difference in cell proliferation on formamide/silk films. The results indicated that formamide/silk films might be used as a corneal stroma repair material and worth of further investigation.
The purpose of this study is to discuss the feasibility of establishing capsaicin pain model and the possibility to evaluate different degrees of pain by the heart rate variability (HRV). It also aims to investigate the changes of autonomic nervous activity of volunteers during the process of pain caused by capsaicin. A total of 30 volunteers were selected, who were physically and mentally healthy, into the study. To assess the effects of capsaicin on the healthy volunteers, we recorded the Visual Analogue Scale (VAS) scores after the capsaicin stimulus. Additionally, the electrocardiogram signals and HRV analysis index before and after stimulating were also recorded, respectively. More specifically, the HRV analysis indexes included the time domain index, the frequency domain index, and the nonlinear analysis index. The results demonstrated that the activity of the autonomic nerves was enhanced in the process of capsaicin stimulus, especially for the sympathetic nerve, which exhibited a significantly differences in HRV. In conclusion, the degree of pain can be reflected by the HRV. It is feasible to establish a capsaicin pain model. And in further experiments, HRV analysis could be used as a reference index for quantitative evaluation of pain.