ABSTRACT
BACKGROUND: Silk fibroin, the main component of silk fibroin biofilm, is a natural protein, but it is still a heterologous protein to the body. Its immunogenicity/toxicity is an important factor in determining the development prospects. OBJECTIVE: To evaluate the toxicity of absorbable silk fibroin biofilm and its degradation products on the rat immune system by muscle implantation experiments in rats. METHODS: Ten Wistar rats from Beijing Weitong Lihua Experimental Animal Technology Co., Ltd. were implanted with a long strip of 1 mm× 10 mm in the right gluteal muscle to observe the implant absorption and determine the implantation cycle. Seventy-two Wistar rats were assigned into control and experimental groups (n=36/group, 18 in either sexes) . A long strip of 1 mm×10 mm was implanted into the rat right gluteal muscle in the experimental group, and the control group received no implantation. Some of the rats were taken for histological examination and calculate the organ/weight ratio, at 26 weeks postoperatively. The spleen lymphocyte proliferation ability, NK cell activity, cell classification of T lymphocytes, and levels of interleukin 2 and tumor necrosis factor α were detected. Another part of the animals was taken for macrophage phagocytosis of erythrocytes cell capacity and antibody producing cell count. RESULTS AND CONCLUSION: (1) Silk fibroin biofilm was completely absorbed after implanted into the rat muscle for 26 weeks. (2) In female or male Wistar rats, the immune organs in the experimental group showed no significant changes in the appearance, weight and histological examination. There were no significant differences in the hematological indexes (hemoglobin, red blood cell count, hematocrit, blood platelet count and white blood cell count and classification) , spleen lymphocyte proliferation, NK cell activity, the ratio of T lymphocytes and their subpopulations, and the levels of interleukin 2 and tumor necrosis factor α had no significant differences between two groups (P> 0.05) . (3) In female or male Wistar rats, the macrophage phagocytosis of chicken erythrocytes cell capacity and antibody producing cell count showed no significant differences between two groups (P> 0.05) . (4) These results indicate that silk fibroin biofilm causes no immunosuppression or immunostimulation on immune organs, immune cells and immune molecules (cytokines) of rats.
ABSTRACT
Objective To develop a method for determination of serumal copper ion in rabbit with implantation of copper intrauterine device.Methods At different time points after implantation,the serumal copper ion concentrations were determined by microwave digestion-inductively coupled plasma mass spectrometry(ICP-MS) using scandium(Sc) and indium(In) as internal standards to compensate sample matrix effects,and the pharmacokinetics parameters were calculated in order to reflect copper ion release and metabolic rule.Results The serumal copper ion concentrations were kept at a low and stable level.The recoveries were in the range of 98.7%-113.3%,with the relative standard deviations of less than 5.0%.Conclusion The analytical method is simple,fast,and can be used for the determination of serumal copper ion in rabbit.
ABSTRACT
This study set out to determine the immunomodulatory effects of a health food high-peptide meal in immunodeficient mice that was induced by either hydrocortisone (HY) or cyclophosphamide (CP). Five separate trials were performed in which animals were randomly divided into 5 groups of 12 mice for each experimental trial. Group 1 served as the vehicle control. Animals assigned to groups 3-5 (dose groups), were each administered once daily with 1.67, 3.33 or 6.67 g kg(-1) body weight of a high-peptide meal, respectively, for 30 consecutive days. Animals from groups 2 to 5 that were included in trials 1 to 4, each received an intramuscular administration of HY at 40 mg kg(-1) body weight on days 22, 24, 26, 28, 30. Animals from groups 2-5, in trial 5, each received an intraperitoneal administration of CP at 50 mg kg(-1) body weight, on days 26 and 27. On day 31, all groups of mice were differentially screened for immunomodulatory activity following the conclusion of the above experiments. In HY-treated mice, the high-peptide meal accelerated the recovery of the phagocytic function of both macrophages and the reticuloendothelial system, and restored NK cell activity. In CP-treated mice, the high-peptide meal promoted a humoral immune response to sheep red blood cells (SRBCs). These results demonstrated the immunomodulatory effects of a high-peptide meal.
