Study of antibacterial effect of mononuclear cells in liver lavage solution / 器官移植

ABSTRACT

Objective To evaluate the antibacterial effect of mononuclear cells(MCs)in the liver lavage solution. Methods For in vitro experiment, MCs were col ected from the liver lavage solution of SD rats and divided into the supplement of interleukin(IL)-15 and non-supplement groups. The MCs were co-cultured with Pseudomonas aeruginosa (P. aeruginosa)for 4 h and then the supernatant was collected and MCs were lysed. The bacterial load in the lysate was detected after LB plate culture. The levels of interferon(IFN)-γand tumor necrosis factor(TNF)-αin the supernatant were measured by enzyme-linked immune absorbent assay(ELISA). For in vivo experiment, 40 SD rats were administered via tracheal injection of P. aeruginosa solution at a dose of 1×109 CFU/mL and randomly divided into four groups(n=10).In the control group, physiological saline was given via gavage. In the immunosuppression group, tacrolimus(FK506)was delivered via gavage. In the MC group, MCs at a dose of 1.0×108 was given via intravenous injection after use of FK506. In the IL-15 pretreated-MC group, IL-15 pretreated-MCs at a dose of 1.0×108 were administered via intravenous injection after application of FK506. The lavage solution of pulmonary alveolus and the rat lung tissue were col ected. The bacterial load was detected after LB plate culture. The expression of IFN-γand TNF-αin the pulmonary alveolus and lung tissue were measured by ELISA and Western blot. Results Compared with MCs alone, IL-15 pretreated-MCs exhibited significantly higher antibacterial capability in vitro. The CFU was 35%of untreated MCs. The synthesis and release capabilities of IFN-γandTNF-αweresignificantlyenhanced.Comparedwiththecontrolgroup,thequantityofimmunecelsinthelungtissuewas decreased and the bacterial load in the lung tissue and the lavage solution of pulmonary alveolus was significantly increased, whereas the expression levels of IFN-γand TNF-αtended to decline in the immunosuppression group. Administration of IL-15 pretreated-MCs significantly enhanced the quantity of immune cel s in the lung tissue, decreased the bacterial load and increased the secretion of IFN-γand TNF-α. Conclusions MCs in the liver lavage solution exhibit favorable antibacterial activity.Underimmunosuppressioncondition,thedefensecapabilityofthehostagainsttheopportunisticpathogenicbacteria is significantly enhanced.