Establishment Of Azithromycin-induced Liver Injury Model In Mice And The Molecular Pathological Study During The Process

Objective Establish the acute liver injury model induced by Azithromycin andstudy the molecular pathological changes during the process Methods300healthymice, were divided into three groups,100mice each group.90mice in Each group,0.3%azithromycin solution (200mg/kg^-1,400mg/kg^-1,800mg/kg^-1) were injectedwith into abdominal cavity to establish the model of acute liver injury in mice, theremaining10mice used as control group. The mice were sacrificed at0h,3h,6h,12h,24h,30h,36h,42h,48h and54h after injection （each for10mice）. The enzymeactivities of ALT and AST in serum were determined. The pathological changes wereobserved through the HE staining of liver tissue of mice at each time point; Theprotein expression of PCNA, Bcl-2, Bax, HSP70, HSP27, TNF-α and VEGF weredetected by Western blotting during the process. The relative protein expression valuewere calculated with software Gel Pro4.0. Results Compared with the controlmice, changes of serum ALT and AST activity in200mg/kg azithromycin group is notobvious; In the400mg/kg group, ALT and AST activity increased at12h, decreasedgradually at24h and returned to normal at54h; in the800mg/kg group, the ALT andAST activity were significantly increased （P<0.05）, up to the peak at24h, began todecrease at30h, and recovered to normal at54h. after injection of200mg/kg or400mg/kg azithromycin, the histologic changes of mouse liver is not obvious; afterinjection of800mg/kg azithromycin,the liver’s structures became abnormal.thehistopathology indicates that At24h, the liver injury reached to the highest level, thenbegan to improve gradually, and return to normal at54h. The protein expression levelof PCNA, Bcl-2, Bax, HSP27, HSP70, TNF-α and VEGF changed significantly at3h,6h,12h,24h,30h,36h,42h,48h,54h in the acute liver injury mice induced byazithromycin （P<0.05）. From6h to30h after injection, the protein expression ofPCNA were significantly decreased, and increased after36h, decreased at42h again, increase later, decrease after54h. The protein expression of Bcl-2were significantlydecreased after azithromycin injection. It decreased to the lowest levels at6h, and thenbegan to increase at30h, it decreased again after36h and42h. After azithromycininjection the protein expression of Bax were increased gradually and it increased to thehighest levels at12h. Then decreased and return to normal gradually. The proteinexpression of HSP27increased from3h to6h, then decrease,reached to the lowestlevels at30h. Then return to normal level gradually. The protein expression of HSP70were significantly increased after azithromycin injection and it increased from3h to12h, then decreased at24h, return to normal level gradually. The protein expression ofTNF-α were significantly increased, peaked after30h, then decrease gradually. TNF-αincreases cell membrane permeability, so secreted a lot first, but to much TNF-αaggravate the liver injury, As a result TNF-α protein expression decrease gradually inlater stage; The protein expression of VEGF began to increase after24h afterazithromycin injection, reched to the highest levels at30h, decrease after36h,gradually restored to normal agter48h. Conclusion1.800mg/kg of azithromycininjection successfully established acute liver injury model in mice.2. The proteinexpression of PCNA, Bcl-2, Bax, HSP27, HSP70, TNF-α,VEGF significantlychanged in the liver of mice during acute liver injury. These factors may playimportant roles during acute liver injury.