| Objective This study aimed to evaluate the effect and the underlying mechanisms of Paeoniflorin and Paeoniflorin in combination with Fluconazole on systemic Candida albicans infection in the mouse model.MethodsFor the experiments,the mice were randomly divided into five groups,the Paeoniflorin group(PF),the Fluconazole group(FCZ),the Paeoniflorin-Fluconazole combination group(PF + FCZ),the Positive Control group(PC)with C.albicans injection and the Negative Control(NC)group without injection of C.albicans.The fungal pathogen,C.albicans(ATCC5314),were injected via caudal vein.Five days before injection of C.albicans,all mice were pretreated daily with PF resp.by normal saline solution.After infection with the fungal pathogen,the mice were treated with PF,FCZ,PF-FCZ combination or resp.with normal saline for next ten consecutive days.We observed and recorded the physical changes and time of death.To analyse the immune-reaction,blood samples were taken from the superior ophthalmic vein at day 10.Cytokines were measured by luminex and the percentage of the lymphocytes Thl,Th2 and Th17 were measured by flow cytometry.The severeness of the infection were evaluated by recording the histopathological changes of livers,spleens and kidneys,and by quantification of the fungal infection.At day 30,the mice were sacrificed to analyse kidneys,livers and spleens.These were removed aseptically,weighed,and plated on Sabourand’s agar to evaluate the amount of colony forming units.Result(1)The average survival time 30 days after infection were 8.2±1.75 for PC,10.4±2.50 for PF,29±3.16 for FCZ,24.6±6.55 for PF+FCZ and 30±0 for the non-infected group NC.The survival rate of the PC in comparison to the PF treated mice is significant higher(p<0.05).The survival time of mice treated with PF and FCZ was significantly decreased in comparison to mice treated only with FCZ(p<0.05).(2)In the blood serum the level of IFN-y,IL-17 and IL-22 were higher in the PC group in comparison to the PF group(P<0.05).The level of IFN-y,IL-17 and IL-22 in the PF+FCZ group were significantly decreased in comparison with the FCZ group.But the level of IL-4 was higher in the PF and as well in the PF+FCZ group compared to the PC resp.FCZ group(P<0.05).(3)Flow cytometry was used to detect CD4+ T lymphocyte differentiation in the mouse model.Compared to the PC group,the percentage of IFN-y+CD4+ T and IL-17+ CD4+T cells were significantly decreased in the PF group(P<0.05).Thl(IFN-γ+CD4+)and Th17(IL-17+CD4+)cells in PF+FCZ group are significantly decreased compared with the FCZ group.The proportion of IL-4+CD4+ T cells in PC group were significantly increased in comparison with the PF group(P<0.05).Also in the PF+FCZ group the proportion of IL-4+CD4+T cells were increased,compared to FCZ group(P<0.05).(4)The amount of C.albicans colony forming units of the kidneys were converted to logarithm lg(X).At day 10 the mean±SD of PC were 4.97±0.65,PF 5.10±0.37,FCZ 3.21±0.11,PF+FCZ 4.61±0.14 and of NC were 0.The fungal colony forming units in the kidney of mice treated with PF were increased compared with PC(P<0.05).Also,the PF + FCZ mice had more fungal colonies compared to FCZ mice(P<0.05).At the day 30,the numbers of fungal colonies in PF+FCZ group(5.03±0.05)were significant higher compared to the FCZ group(3.49±0.52)(P<0.05).Conclusion1.Here,we first demonstrated that PF and also PF in combination with the antifungal drug FCZ increased fungal burden in kidney and shortened the survival time.PF was aggravating the infection of C.albicans in mouse model.Hence patients with fungal infection should avoid to uptake PF.2.The results of this study indicated that the augment of systemic C.albicans infection in mouse models after exposure to PF,could be associated with inhibition of Thl,Thl 7 differentiation and promotion of Th2 differentiation in vivo. |
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