Establishment and analysis of an animal model for nutcracker syndrome

This study investigated the effects of renal vein congestion of varying durations on kidney damage by establishing an animal model of Nutcracker Syndrome (NCS). In addition, we assessed whether renal damage improved after relieving the congestion.

We established a rat model of NCS and relieved renal congestion through secondary surgery, with renal vein reperfusion confirmed by animal ultrasound. Histopathological changes in congested kidneys were evaluated at 3, 6, and 9 days using HE and Masson staining, and the expression of renal injury factors was determined using q-PCR.

Renal tissue pathology changes were evident with prolonged obstruction time. Compared to the sham-operated group, no apparent fibrosis was observed in the kidneys at 3 days post-congestion, whereas fibrosis was most severe at 9 days post-congestion, with no significant improvement observed even after blood flow restoration. Six days post-congestion relief, some alleviation of renal fibrosis occurred. q-PCR results indicated a significant reduction in the expression of fibrosis markers after 3 or 6 days of renal vein ligation release. Following blood flow restoration on the 9th day post-congestion, no significant changes in fibrosis markers were noted.

Prolonged renal vein congestion in a rat model of NCS resulted in severe kidney damage and significant fibrosis after 9 days. While relieving congestion within 6 days led to some improvement, no reduction in fibrosis occurred after 9 days, underscoring the importance of congestion duration in renal pathology.