Objectives: The role of SOST/sclerostin in mediating tissue fibrogenic response to injury/inflammation remains largely unknown. Thus, we conducted this study to determine whether SOST/sclerostin plays a role in renal interstitial fibrosis (RIF) for the first time.
Methods: Unilateral ureteral obstruction (UUO) was performed to create obstructive kidney injury model. Twelvemale SOST knockout (SOST KO) mice and 12 age-matched wild-type (WT) mice were divided into three groups: sham surgery, UUO 3 d and UUO 7 d. The mice were sacrificed at each time point and kidney tissues were collected. Histopathological changes were evaluated by hematoxylin and eosin and Masson staining, while α-smooth muscle actin (α-SMA), type I collagen (Col-I) and fibronectin (FN) expression levels were detected by RT-PCR and western-blot.
Results: In sham control group, neither WT nor SOST KO exhibited fibrotic change. On 3 days after UUO, total renal histopathological score and fibrotic area were aggravated and α-SMA, Col-I and FN expressions were upregulated, but no difference was observed between WT and SOST KO. On 7 days after UUO, compared with WT, SOST KO mice showed higher total renal histopathological score and fibrotic area percentage, as well as a higher level of fibrogenic marker mRNA/protein expression (except for α-SMA mRNA and FN mRNA).
Conclusion: It is supposed that SOST gene is involved in the regulation of RIF progression. In obstructive kidney injury, SOST gene deletion would probably enhance renal fibrogenic response and promote the progression of RIF. But more evidences are needed to further identify the role of SOST/sclerostin in mediating RIF progression.
Keywords: LRP-6; SOST gene; renal interstitial fibrosis; sclerostin; unilateral ureteral obstruction.