Study On The Number Of Circulating Blood Cells In Silkworm Immunity

The Silkworm's blood circulatory system is an open circulatory system in which contained all internal tissues and organs.When the pathogen breached the integument,intestinal tract,trachea and other physical barriers,the first thing it would face is blood.Blood played an important role in innate immunity.Silkworm innate immunity includes humoral immunity and cellular immunity.Important innate immune response mechanisms such as phagocytosis,embedding and melanosis are closely related to circulating hemocyte.However,changes in the number of circulating hemocyte during immunization have not been investigated in detail.This paper investigated the changes and effects of the number of hemocyte,size of hematopoietic organs and hematopoietic regulatory factors in silkworm larvae after injection of E coli.The results were as follows:To observe the number of circulating hemocyte and the size of hematopoietic organs of silkworm larvae after immune attack during stage 5 to wandering.The results showed that the number of hemocyte in all larvae dropped immediately after they were injected with the bacteria,then rose to a peak,and gradually dropped back to normal.The number of hemocyte achieved peake at 6 hours after injection in the early stage and 12 hours after injection in the late stage.The time it takes for the number of growing blood cells to peak is delayed.The hemopoietic organs increased slightly in the middle and early ages of 5 and then returned to normal,but the change was not obvious in the middle and late stages of 5.The changes between the number of blood cells and the size of the hematopoietic organs were not consistent.The number of blood cells of the non-treated larvae reached a peak at the age of 5,then gradually decreased to a stable state at the 6 days stage 5,and then increased slightly at the wandering stage.However,the hematopoietic organs gradually increased with the growth of larvae to reach the maximum at age 5 and 6 days,and became significantly smaller at the end of stage 5 until complete dissociation.The number of hemocyte did not increase with the size of the hematopoietic organ.Therefore,there was no significant positive correlation between the number of circulating hemocyte and the size of hematopoietic organs in 5-instar larvae under normal and immune conditions.The hemocyte numbers of silkworm varieties such as jingsong,haoyue,xianghui,furong,7532,932 and their hybrids were investigated.It was speculated that the number of blood cells was related to silkworm health.The expression of BmBCFI,Bmush and BmLz in silkworm blood cells from the age of 5 liangguangerhao was significantly higher than that of haoyue.These hematopoietic regulators may be related to health.The expression levels of BmBCFI,BmUsh and BmLz were significantly increased at the peak of the blood cell count after immune attack,when the blood cell count was lowest,highest and normal.This again suggests that these hematopoietic regulators may be related to immunity.Intervention experiments showed that the number of plasma cells and total blood cells decreased when BmBCFI gene expression decreased.Decreased expression of BmUsh and BmLz genes resulted in decreased number of oenocytoid.That is,BmBCFI may be related to plasmatocytes,and BmUsh and BmLz may be related to oenocytoid.In addition,to reduce the BmBCFI and BmUsh gene,the cactus on the Toll way genes and Imd relish gene expression significantly lower on the way.This suggests that hematopoietic regulatory factors BmBCFI and BmUsh are related to immunity.