Studies On The Relevance Of Candida Albicans Infection Of The Alimentary Tract And Deficiency Of Spleen And Its Immunological Mechanism

Purpose:To investigate the susceptibility of Candida albicans infection of alimentary tract in the state of deficiency of spleen and the immunological mechanisms.To illuminate the characteristics of change of susceptibility in deficiency of spleen,to further control their infection.To illuminate the relationship between immunological functions and Candida albicans and some immunological changes before and after the infection.To illuminate the immunological mechanisms of Candida albicans infection in the state of deficiency of spleen,for the prevention and treatment of the infection.Material and method:The experimental mice were randomly divided into four groups,that is,the normal control group(A group),deficiency of spleen model group(B group),Candida albicans infection in normal group(C group),deficiency of spleen with Candida albicans infection group(D group).The animal model of spleen deficiency was prepared by using of irregular-feeding and overstrain methods.The mice in group C and D were fed with suspension of Candida albicans, in the following 3 weeks,mice in each group were observed changes in body weight and general condition.The average survival days and survival rate were recorded and calculated.The number of living Candida albicans in fecal and kidney was detected;spleen index and thymus index were also measured.The jejunum of the mice were prepared with HE staining method,and the morphological changes of jejunum were observed with optical microscope.Ultrastructural changes of small intestine were observed with electron microscopy.The total number of peripheral blood leukocytes,neutrophils,lymphocytes and mononuclear cells,and RBC number and hemoglobin content of the change were also measured with animal blood analyzer.The expression of immunoglobulin A(IgA),serum interleukin-1β (IL-1β),macrophage tumor necrosis factor-α(TNF-α),spleen cells fromγ-interferon(IFN-γ) and interleukin-10(IL-10) content in intestinal tissue of spleen deficiency mice were detected with application of enzyme-linked immunosorbent assay(ELISA).Using reverse transcription / polymerase chain reaction(RT-PCR) method detected the expression of IFN-γmRNA and IL-10mRNA level in the intestinal tissue.Results:1.Effects on body weight and general condition of spleen deficiency mice with Candida albicans infection of the alimentary tract.Body weight in spleen deficiency mice was significant lighter than normal mice(P＜0.01),with the addition of poor general condition.In normal mice after infection,no significant changes in body weight,and the weight of spleen deficiency infected mice decreased significantly(P＜0.01).2.Effects on the survival days and survival rate of spleen deficiency mice with Candida albicans infection of the alimentary tract.The survival days of spleen deficiency mice were reduced(P＜0.05),the survival rate dropped to 75%;the average survival days were no significant difference in normal mice infected with Candida albicans.And the average survival days was reduced significantly in spleen deficiency mice infected with Candida albicans,the survival rate also dropped to 55%.3.Effects on the number of living fecal bacteria of spleen deficiency mice with Candida albicans infection of the alimentary tract.Normal mice after infection,the number of fecal living bacteria appeared a downward trend after an increase in initial stage,and that number shows an increasing trend,and always higher than the former in infected spleen deficiency mice.In the first six days after infection,the number of fecal living bacteria of the two groups mice have a statistically significance difference(P＜0.05); the first 9 days,12 days,the first 15 days and 18 days,both statistically significance difference(P＜0.01). 4.Effects on the number of living renal bacteria of spleen deficiency mice with Candida albicans infection of the alimentary tract.In normal mice after infection,a relatively small number of living bacteria was observed in kidney,and that number have a marked increase in the kidney of infected spleen deficiency mice(P＜0.01).5.Effects on the spleen index and thymus index of spleen deficiency mice with Candida albicans infection of the alimentary tract.The weight of spleen and thymus in spleen deficiency mice was lower than that of normal mice,but not statistically significant.After Candida albicans infection in mice,the spleen index and thymus index were significantly higher, with statistically significant differences(P＜0.05 or P＜0.01).In particular, increased weight of spleen deficiency mice became more evident.6.Effects on morphology of small intestinal submucosa of spleen deficiency mice with Candida albicans infection of the alimentary tract.Intestinal villi in spleen deficiency mice became slightly shorter,and scattered free surface epithelial.In normal mice after infection,intestinal villi became shorter and sparse,and free surface epithelial became cubic form; the inherent membrane had vacuole-like change with mild edema in cells.In infected spleen deficiency mice,small intestinal villi became sparse and incomplete,with cubic columnar epithelium changes,the inherent membrane had vacuole-like change.7.Effects on ultrastructure of small intestinal submucosa of spleen deficiency mice with Candida albicans infection of the alimentary tract.In normal mice after infection,microvilli became sparse and different in length and size,slightly swollen mitochondria in the cytoplasm,a looser ridge, and some showed vacuolated changes.In infected spleen deficiency mice, microvilli became untidily sparse and shorter,mitochondrial swelling, disappearance of ridge,vacuolated changes,and with addition of expansion of the endoplasmic reticulum and ribosome falling off,etc.8.Effects on the number of peripheral blood cells of spleen deficiency mice with Candida albicans infection of the alimentary tract.The number of peripheral blood hemoglobin content of red blood cells are reduced in spleen deficiency mice,especially in the mice after infection(P＜0.01).the number of leukocytes in infected spleen deficiency mice was significantly increased(P＜0.01);the number of mononuclear cells increased significantly(P＜0.01)in normal mice,and neutrophils also significantly increased.9.Effects on the Secretion of TNF-αof peritoneal macrophages of spleen deficiency mice with Candida albicans infection of the alimentary tract.Compared to the normal group,the Secretion of TNF-αof peritoneal macrophages was reduced,and the infected normal mice was increased,both have significantly different(P＜0.05);the Secretion of infected spleen deficiency mice was significantly higher than other groups(P＜0.01).10.Effects on the content of serum IL-1βof spleen deficiency mice with Candida albicans infection of the alimentary tract.There was no significant change in serum IL-1βcontent in spleen deficiency mice;in final stage of infection in normal mice,serum IL-1βcontent increased, but without statistical significance,and in infected spleen deficiency mice, serum IL-1βcontent was significantly higher(P＜0.01).11.Effects on IgA content of intestinal tissue of spleen deficiency mice with Candida albicans infection of the alimentary tract.IgA content of intestinal tissue decreased significantly(P＜0.01)in spleen deficiency mice,compared to normal mice.After infection,intestinal IgA secretion also declined,especially in infected spleen deficiency mice,the IgA content was significantly lower than the other groups(P＜0.01).12.Effects on the expression of IFN-γand IL-10 of spleen of spleen deficiency mice with Candida albicans infection of the alimentary tract.The expression of IFN-γand IL-10 in normal mice after infection was higher than the normal group,but no significant difference;and the expression in infected spleen deficiency mice was significantly higher than the other groups (P＜0.01) in the final infectious stage.13.Effects on the expression of IFN-γmRNA and IL-10mRNA of intestinal tissue of spleen deficiency mice with Candida albicans infection of the alimentary tract.Compared to the normal group,the expression of IFN-γmRNA in spleen deficiency mice was increased(P＜0.01),and that of IL-10mRNA had no obvious difference.Compared to spleen deficiency mice,the expressions of IFN-γmRNA and IL-10mRNA were both significantly increased(P＜0.01) in the other groups. Compared to infected normal groups,the expression of IFN-γmRNA was still at a high level state in final infectious stage of infected spleen deficiency mice, but the expression of IL-10mRNA was reduced(P＜0.05).Conclusion:1.The susceptibility of Candida albicans of mice was enhanced in a state of spleen deficiency.Which led to a significant drop in body weight,increasing of spleen index and thymus index,the shortened average number of days,the decreased survival rate,and a sustaining increasing number of living bacteria in feces and kidney.2.After Candida albicans infection in the alimentary tract in a state of spleen deficiency,IgA content of intestinal tissue decreased significantly,leading to hypofunction of the intestinal function of local immune defense,which caused the morphological changes of intestinal mucosa and pathological changes of intestinal epithelial cell ultrastructure.Meanwhile,bacteria could be disseminated into the blood and other parts of the body,so that cause reduction in the number of red blood cells in peripheral blood,hemoglobin decreased,the proliferation of a large number of inflammatory cells in vivo.3.Whether pathogenic or not of Candida albicans infection of the alimentary tract is closely related to the immune system of mice,especially in the hypofunction state of immune defense which is greater harmful to mice and at the same time,may further aggravate the deficiency state or infection,In the process of body against Candida albicans infection,a variety of immune cells and cytokines involved in immune response.