Effect of cyclin-dependent kinase 2 recombinant lentivirus in rats with lipopolysaccharide-induced acute lung injury

Abstract

Objective To investigate the effect of cyclin-dependent kinase 2 (cdk2) recombinant lentivirus in rats with lipopolysaccharide (LPS)-induced acute lung injury (ALI). Methods Thirty-six adult SD rats were divided into control group, LPS model group and gene intervention group according to the random number table, with 12 rats per group. Rats with LPS-induced ALI were established by intratracheal injection of LPS. Saline solution (60 μL/kg) was injected in control group at the time point of 0, 24, 48 h respectively. Control-lentivirus (60 μL/kg) and cdk2 recombinant lentivirus (60 μL/kg) were injected respectively in LPS model group and gene intervention group at the time point of 0 h and 24 h. After 48 h, LPS (60 μL/kg) with isotonic saline solution were injected in both LPS model group and gene intervention group. Lung tissue samples from right-lower areas were collected at 24 h postinjury to evaluate the pathological changes with HE staining. Expressions of cdk2, clara cell secretory protein (CCSP), phospholipase A2(PLA2) and p-C/EBP β protein were detected by Western blot. Inflammatory factors of tumor necrosis factor-α(TNF-α), interleukin (IL)-1β, IL-6 and IL-10 in serum were measured with ELISA method. Results Inflammatory infiltration and damage to the alveolar structure were serious in LPS model group than control group, while inflammatory infiltration decreased significantly and alveolar structure tended to be normal in gene- intervention group. Expression of Cdk2 in control group (1.00±0.21) and LPS model group (0.93±0.17) were similar, but both were lower than that in gene intervention group (4.29±0.73) (P<0.05). Expression of CCSP in gene intervention group (3.19±0.38) was significantly higher than that in control group (1.00±0.20) and LPS model group (0.32±0.19) (P<0.05). Expression of PLA2 in LPS model group (4.49±0.51) was higher than that in control group (1.00±0.13) and gene intervention group (1.76±0.26) (P<0.05). Meanwhile, the variation of p-C/EBPβ concentration among the groups was similar to CCSP. Expression of TNF-α in LPS model group[(196.34±30.17)pg/ml] was higher than that in control group [(71.24±5.13)pg/ml] and gene intervention group[(86.32±11.02)pg/ml](P<0.05). Changes in IL-1β, IL-6 and IL-10 among the groups were similar to TNF-α. Conclusions Over-expression of Cdk2 plays a protective role for LPS-induced ALIby up-regulating CCSP and down-regulating inflammatory factors such as PLA2, TNF-α, IL-1β, IL-6 and IL-10, as may relate to the phosphorylation of C/EBPβ. Key words: CCAAT-enhancer binding protein-beta; Phosphorylases; Cyclin-dependent kinase 2; Endotoxins; Acute lung injury