Effects Of Silk Peptide On Immunologic Function In Mice

Silk is a composite fiber, and it is made of silk fibroin and sericin protein. In silk, thecontent of fibroin is about75%and the content of sericin is about25%, and it also contains asmall amount of waxiness, carbohydrate, pigment and inorganic constituent. The posteriordivision of silkgland synthetizes and secretes fibroin, and fibroin cant not soluble in water.The middle division of silkgland synthetizes and secretes sericin globular protein. Accordingto the statistics of ministry of commerce in2010, the volume of production of mulberrysilkworm cocoon is618000tons, and the mulberry silk is96000tons. Silk can bedisintegrated into silk peptide by acid, alkali or enzyme. According to the published articles,silk peptide have many biological activities, such as antioxidation, anticoagulation,antitumous effect, strengthen the mineral elements absorption, inhibition of tyrosinase activity,UV protection effect and so on. In order to do further discussion to the biomedical functionsof silk peptide, in this paper we will study the acute toxicity of silk peptide in mice and theeffects of silk peptide on immunologic function in normal and immunocompromised mice.We first studied the acute toxicity in mice by gavage high doses of silk peptide, and thenstudied the effects of silk peptide on immunologic function in normal mice. We found thatthere is no unified standard about how to make immunocompromised model mice. So we didsome preliminary experiments to determine the method for immunocompromised model.Then we studied the effects of silk peptide on immunologic function in immunocompromisedmice, the main contents are as follows:(1) We studied the acute toxicity in BALB/c mice by gavage30000mg/kg doses of silkpeptide (2times, interval6h). Tested the various indexes of the mice, such as physical signs,weight, blood routine, liver and kidney function and autopsy histologic examination. Theresults show that there was no significant difference between the test group and the blankcontrol group. According to the acute toxicity standard of compounds through the mouth, thesilk peptide belongs to the non-toxic level.(2) We studied the effects of silk peptide on immunologic function in normal mice bygavage4doses of silk peptide for30consecutive days. The results show that treatment withhigh dosage silk peptide enhanced the phagocytic index.(3) We first determined the method for CY-induced immunocompromised model. Themice were intraperitoneal injected150mg/kg CY (2times, interval2days), there is a significant reduction in the mice immune system function after4days. Then we studied theeffects of silk peptide on immunologic function in CY-induced immunocompromised mice byinject3doses of silk peptide for45consecutive days. The results show that treatment withsilk peptide significantly improved the thymus and spleen indices, carbon clearance index,splenocyte proliferation and NK cytotoxicity activity. Silk protein peptide can effectivelystrengthen and protect the immunosuppressive function of the immune system in mice. Silkpeptide can effectively strengthen and protect the immune system function in CY-inducedimmunosuppressive mice.(4) We also first determined the method for X-ray-induced immunocompromised model.The mice were accepted one-time whole body irradiation of2Gy X-ray, there is a significantreduction in the mice immune system function after24hours. Then we studied the effects ofsilk peptide on immunologic function in X-ray-induced immunocompromised mice by inject3doses of silk peptide for45consecutive days. The results show that treatment with silkpeptide significantly improved the thymus and spleen indices, carbon clearance index,splenocyte proliferation and NK cytotoxicity activity. Silk protein peptide can effectivelystrengthen and protect the immunosuppressive function of the immune system in mice. Silkpeptide can effectively strengthen and protect the immune system function in X-ray-inducedimmunosuppressive mice.(5) We studied the effects of7doses silk peptide on spleen lymphocyte proliferation invitro by MTT method. The results show that the certain concentration range of silk peptidecan stimulate the spleen lymphocyte proliferation ability in vitro.