| Background:The prevalence of chronic kidney disease(CKD)is increasing globally year by year,and the total prevalence of CKD in China is currently as high as 10.8%,which poses a huge medical burden to society.Renal fibrosis is a common pathological feature in the progression of CKD with various etiologies.Therefore,it is generally believed that understanding and elucidating the pathogenesis of renal fibrosis as well as developing safe and effective novel compounds play a key role in reducing the prevalence of CKD and delaying the progression of CKD lesions.Our team has previously found that FFNT25,a novel antifibrotic drug,can promote renal tissue repair after recanalization in a miniature pig model of unilateral ureteral obstruction recanalization(R-UUO).However,due to the limitations of our previous experiments,the preliminary results only tentatively demonstrated the safety and antifibrotic effect of FFNT25 in the R-UUO model,plus the potential mechanism.This study aimed to further confirm the antifibrotic effect of compound FFNT25 and the potential mechanism.Methods:This study was divided into two parts.Firstly,in vivo,we utilized the8-week-old male SD rats to conduct the unilateral ureteral obstruction(UUO)model.The rats were randomly and equally divided into four groups:(1)Control group: normal SD rats,(2)Sham-operated: SD rats were treated with sham surgery,(3)UUO-operated + vehicle,(4)UUOoperated + FFNT25,two weeks after UUO,the rats were gavaged with either FFNT25 or vehicle for another two weeks.The physiological and biochemical indexes were recorded and detected in each group.q PCR,Western Blot,and immunohistochemical staining were used to detect the level of m RNAs transcription,protein expression and the localization of protein to reflect renal fibrosis.Subsequently,in vitro,we established the cellular fibrosis model with renal tubular epithelial cells(HK-2)challenged by TGF-β1.Overexpression of β-catenin or PAI-1 and si RNA interference were used to observe the effect of compound FFNT25 on TGF-β 1 induced mesenchymal transition(EMT)of HK-2,m RNA transcription and expression of collagen fiber related molecules and activity of β-catenin/PAI-1 pathway.Results:(1)In vivo,SD rats did not show obviously signs of gastrointestinal discomfort such as vomiting and diarrhea after FFNT25 treatment.FFNT25 did not alleviate UUO-induced weight loss in rats,but promoted the recovery of the left/right kidney mass ratio in rats compared to UUO rats.As is shown in PAS staining that FFNT25 significantly improved pathological changes of UUO rats(including renal interstitial edema,and tubular dilatation,brush border loss,tubular epithelial cell shedding and basement membrane exposure,etc.).Masson staining showed that FFNT25 could prevent UUO-induced collagen deposition.Real-time quantitative PCR,Western Blot,and immunohistochemical staining also confirmed that FFNT25 inhibited the protein expression of type I collagen,type III collagen and fibronectin,the main components of ECM caused by UUO model,and reduced the m RNA transcription or protein level of α-SMA,PAI-1,TIMP-1 and TIMP-2 molecules in the kidney of UUO rats(2)In vitro,FFNT25 could ameliorate TGF-β1-induced collagen deposition and EMT in HK-2 cells,along with inhibiting the expression of proteins related to the β-catenin/PAI-1 signaling pathway.Overexpression of β-catenin or PAI-1 decreased the protective effect of FFNT25 on TGF-β1-induced HK-2 cell injury,while performing si RNA interference on PAI-1 enhanced the protective effect of FFNT25 on TGF-β1-induced HK-2 cell injury.Conclusions:(1)FFNT25 can alleviate renal interstitial fibrosis caused by UUO.On the one hand,FFNT25 may improve renal interstitial fibrosis by reducing ECM production;On the other hand,it may promote the degradation of ECM by inhibiting the expression of PAI-1.(2)FFNT25 can attenuate the injury of TGF-β1-induced HK-2.FFNT25 exerts antifibrotic effects through or at least partially through inhibition of β-catenin/PAI-1 signaling pathway. |
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