Therapeutic Effect and Mechanism of Jipei Dilong Ointment on Acute Soft Tissue Injury in Rats

[Objectives]This study was conducted to observe the therapeutic effect of Jipei Dilong Ointment on rats with acute soft tissue injury caused by heavy objects and to explore its action mechanism.[Methods]Thirty six rats were randomly divided into six groups(control group,model group,high-dose Jipei Dilong Ointment group(JP-H),medium-dose Jipei Dilong Ointment group(JP-M),low-dose Jipei Dilong Ointment group(JP-L)and diclofenac group).Except for the Control group,other groups were subjected to modeling of acute soft tissue injury by the weight impact method.All administration was performed once a day for nine consecutive days.The local appearance score and activity disorder score were determined after soft tissue injury in rats.HE staining was used to detect the pathological changes of injured soft tissues in rats.RT-PCR was used to detect the relative mRNA expressions of Bax,Bcl-2,MMP-9 and TIMP-1 in injured soft tissues of rats.Western Blot was used to detect the protein expressions of MMP-9,TIMP-1,TLR4,MyD88 and NF-κB p65 in injured soft tissues of rats.Results were statistically analyzed.[Results]Compared with the model group,Jipei Dilong Ointment could significantly improve the appearance symptoms such as swelling and ecchymosis in the injured area and the movement function of the affected limb(P<0.05).It could also improve the infiltration of inflammatory cells and widening of the intermuscular space caused by injury.Among them,the JP-H group and the diclofenac group had more significant curative effects.After 9 d of administration,each administration group could significantly up-regulate the ratio of Bcl-2/Bax mRNA expression level(P<0.05 or P<0.01),and the ratio of MMP-9/TIMP-1 mRNA expression level showed a downward trend(P>0.05).The expression level of NF-κB p65 protein in each administration group was significantly decreased(P<0.01).The protein expression levels of TLR4 and MyD88 and the ratio of MMP-9/TIMP-1 protein expression level in each administration group decreased to varying degrees.Among them,the JP-H group and diclofenac group significantly decreased(P<0.05).[Conclusions]Jipei Dilong Ointment has the functions of relieving pain,swelling and inflammation.It could improve the local appearance,functional activity and tissue morphology of affected limbs in rats,and has a therapeutic effect on acute soft tissue injury in rats.Its mechanism of action might be related to the inhibition of TLR4/MyD88/NF-κB p65 signaling pathway and the regulation of Bcl-2/Bax and MMP-9/TIMP-1 balance.