Expression of Profibrotic Genes in a Murine Remnant Kidney Model

Abstract

PURPOSE To test the hypothesis that there is increased expression of several profibrotic genes including matrix metalloproteinase–2 (MMP-2), and -9 (MMP-9), and its inhibitors (TIMP-1 and TIMP-2), a disintegrin and metalloproteinase with thrombospondin motif -1 (ADAMTS-1), and fibroblast specific protein-1 (FSP-1) in a murine remnant kidney (RK) model. MATERIALS AND METHODS CKD was created in ten C57BL/6 male mice (20-25 g) by performing a right nephrectomy and ligation of the upper pole of the left kidney (RK). Animals were sacrificed at 42 and 56 days later. Real time polymerase chain reaction (RT-PCR) for MMP-2, MMP-9, TIMP-1, TIMP-2, ADAMTS-1, and FSP-1 was performed in the RK. Histologic evaluation of the RK was performed using Ki-67, α-smooth muscle cell actin (α-SMA), hematoxylin and eosin, and Masson’s trichrome staining. Kidney function was assessed using serum BUN and creatinine. RESULTS The mean serum BUN and creatinine levels at day 42 and 56 were significantly higher than baseline (P <0 .05). By day 42, the mean expression of MMP-2, MMP-9, TIMP-1, ADAMTS-1, and FSP-1 was significantly higher in the RK when compared to normal kidney (P<0.05) and by day 56, only FSP-1 expression increased significantly higher (P<0.05). There was increased fibrosis by Masson’s trichrome, increased Ki-67, with increased α-SMA staining in the RK when compared to normal kidneys. CONCLUSIONS In the RK, there was increased fibrosis with increased α -SMA and Ki-67 staining with significantly increased expression of MMP-2, MMP-9, TIMP-1, ADAMTS-1, and FSP-1.

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“…As stated earlier, even before fistula or graft creation several important systemic and vascular changes take place. [14][15][16][17] The inherent uremia of ESRD increases inflammation and oxidative stress. 18,19 These changes are evidenced by increases in many inflammatory cytokines, namely, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and proliferate cytokines, such as transformative growth factorβ (TGF-β).…”