Research Of Penetration And Migration Of Tachyzqite And Histological Lesions In Kunming Mice Fed CT1 Strain Toxoplasma Gondii Oocysts

This paper was studied in 4 weeks Kunming mice after feeding 1oocyst/mice、10~1oocysts/mice and 10~2oocysts/mice of CT1 Toxoplasma gondii oocysts.At0.5、2、4、6 hours after inoculation(HAI)and 1、2、3、4、5、6、7、50 days after inoculation(DAI)mice were killed.Natural death of mice were performed pathological examination.Tissues of all organs were make paraffin section,which were stained by HE(hematoxylin and eosin)and IHC(immunohistochemistry).The major objective of this paper was to study the migration of tachyzoite and histological lesions of all organs in acute toxoplasmosis(≤10 days)in Kunming mice.And the formation of tissue cyst in chronic infection(≥50days).The main results as follows:1.Procedure of obtain and identification of oocysts of T.gondii in cat feces was discussed.Centrifuge the wet cat feces after rinsing by the sucrose flotation solution,examined the smear with microscopy and checked T.gondii oocysts.And the fecal floation was sporulated 7 days,adding 2% sulfuric acid.Kunming mice were fed three different doses of CT1 Toxoplasma gondii oocysts of which were neutralized with 3.3% sodium hydroxide(Na OH).Both acute toxoplasmosis and asymptomatic infection of Kunming mice showed this procedure meet the requirements of the subsequent experiments.2.Results of intestinal tract infected with high dose of CT1 Toxoplasma gondii oocysts showed: the infection rate of individual small or large intestine was(78.8%)、the whole intestine(84.4%)、the mesenteric lymph nodes(69.7%),and the whole intestine was infected at all killed times.The infection rate of mesenteric lymph nodes were observed from positive guts was 69.7%.There is bleeding and ulcers in jejunum.In the submucosa of the small intestine there was pin-point necrosis,oedema and fibrinous exudation.And focal necrosis of the muscle layers was detected.Free and/or intracellular tachyzoites were detected in the goblet cells、lymphocytes and the intestine lumen.Focal necrosis,oedema,congestive and hemorrhage was seen in the enlarged mesenteric lymph nodes.3.The distribution of tachyzoites in organs showed the low dose group and middle dose group both have the highest infection rate at 0.5HAI,and the rate was decreased with time.Moreover,all animals in the high dose group were infected at all time points.Overall,the number of infected mice gradually increased as the dose increased.We found severe pulmonary congestion and oedema by microscopic examination.There is widespread perivascular inflammation.Splenomegalia and extensive areas of necrosis in spleen.Brain lesions were minor,with scattered tiny necrotic and inflammatory foci,and occasional tiny foci of gliosis were present in the white matter of the brain and perivascular inflammation was observed.Small foci and macrophages in hepatic portal area were seen in the liver.Sever lesions of liver could be seen in low magnification.Tissue lesions from sever to minor is lung> liver> spleen> mesenteric lymph nodes>adrenal> kidney> brain> skeletal muscle> cardiac> others.The rate of tachyzoites positive is mesenteric lymph nodes(33.33%),spleen(10.81%),skeletal muscle(6.31%),heart(5.41%),eye(5.41%),brain(4.50%),liver(3.60%),kidney(3.60%),tongue(1.80%),lungs(1.80%),adrenal(0.90%).4.Numerous of tachyzoites were observed in mesenteric lymph nodes,heart,brain,lung,skeletal muscle,spleen and liver in acute toxoplasmosis(<10days).5.One animal with chronic Toxoplasmosis at 50 DAI was diagnosed as T.gondii positive by the modified agglutination test(MAT).And tissue cysts containing numerous of bradyzoites were observed after making smear from the brain.6.Healthy Kunming mice were injected subcutaneously with the tissue cyst from the brain of chronically infected mice.The average time of death in mice of second cycle is 9.5days and all lung smears were T.gondii positive.Then healthy Kunming mice were injected subcutaneously with the grinding fluid of the lung.The average time of death in mice of third cycle is 10.25 days and all lung smears were T.gondii positive too.The experiment has duplicate the life cycle of CT1 Toxoplasma gondii oocysts from oocysts→ tachyzoite→bradyzoite→ tachyzoite in Kunming mice successfully...