Unilateral Ureteral Obstruction Model for Investigating Kidney Interstitial Fibrosis

This research mainly focus on the mechanism underlying the interaction between macrophage and the renal parenchymal cells in the progression of renal fibrosis, aiming to provide new therapeutic targets for chronic kidney disease. A recent study found that the key macrophage subtype involved in extracellular matrix remodeling has crosstalk with the fibroblast through the insulin-like growth factor signaling pathway, promoting chronic kidney inflammation and fibrosis. Single-cell multi-omics sequencing technology enable researchers to uncover the potential pathogenic mechanism of various kidney disease, such as acute kidney injury, lupus nephritis, primary membranous nephropathy, and IgA nephropathy, providing new insights for targeted therapy. Key mechanisms in kidney disease have been successfully identified, including the roles of KR4, PIST-1, and the signaling pathway of IL-1 receptor-1 in different cells. This provides new insights for the prevention and the treatment of both acute and chronic kidney disease. This research established a more standardized and highly reproducible model of obstructive nephropathy in mice. This model is cost-effective, reliable, and features simple steps with high stability.

[Narrator] To begin, place the mouse on an external heat source in a supine position with the head and neck extended to maintain an open airway. Secure the paws using low-adhesive tape. Use a thermometer to monitor the ambient temperature, ensuring it remains between 37° and 38° Celsius. Apply ophthalmic ointment to the eyes to prevent corneal cirrhosis injury. Use a surgical blade to make a vertical surgical incision of approximately 1 to 1.5 centimeters from the bladder to the lower left edge of the ribs to expose the abdominal cavity. Move the intestine to the right side of the abdominal cavity using a cotton swab moistened with sterile normal saline to expose the left kidney, which is located below the back of the spleen and adjacent to the spine. Using curved iris forceps, clear the fat and connective tissue surrounding the left ureter. After gentle isolation, ligate the left ureter close to the kidney's lower pole using a 4/0 surgical suture. Perform a second ligation between the first ligation and the bladder. Carefully reposition the intestines into the peritoneal cavity. Inject 0.5 milliliters of warm normal saline intraperitoneally to prevent dehydration. Place the recovered mouse back into a clean cage. Administer buprenorphine at 50 micrograms per kilogram by subcutaneous injection for three days. Periodic acid-Schiff, Masson's trichrome staining, and Sirius red staining of renal sections from sham and unilateral ureteral obstruction kidneys are shown here. Tubular dilation, loss of brush borders, cast formation, and tubular epithelial swelling were observed in unilateral ureteral obstruction kidneys using periodic acid-Schiff staining. Interstitial fibrosis progressively increased over time, as indicated by Masson's trichrome staining and Sirius red staining. Western blot analysis showed a time-dependent increase in fibronectin, collagen I, and α-smooth muscle actin expression in unilateral ureteral obstruction kidneys compared to the sham group. Real-time PCR analysis revealed significantly higher mRNA expression of fibrotic markers in unilateral ureteral obstruction kidneys compared to the sham group. Inflammatory cytokines were also elevated in the affected kidneys.