This protocol describes a method for inducing unilateral ureteral obstruction (UUO) in mice to study the progression of tissue fibrosis in obstructive nephropathy. It includes surgical procedures, post-operative care, and methods for fibrosis assessment.
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Method Article
Unilateral Ureteral Obstruction Model for Investigating Kidney Interstitial Fibrosis
In This Article
Summary
Abstract
Kidney fibrosis is the final pathological outcome of progressive chronic kidney disease (CKD). The unilateral ureteral obstruction (UUO) model is widely used to elucidate the molecular and cellular mechanisms underlying kidney interstitial fibrosis and to identify potential therapeutic targets. This model is established in mice through surgical ligation of a unilateral ureter, a procedure that is relatively straightforward and easy to perform. However, the UUO mouse model is known to exhibit significant variability and inconsistency, influenced by factors such as mouse strain, age, sex, anesthesia type, duration of surgery, body temperature during the procedure, the operator's surgical skills, feeding conditions, and the overall health status of the mice. Variations in surgical techniques, suture placement, and the duration of obstruction contribute to the variability in outcomes. Additionally, inconsistent sampling of obstructed kidneys further increases variability in the assessment of kidney fibrosis. This study outlines the process of developing the UUO mouse model and evaluating interstitial fibrosis, discusses the technical challenges contributing to the model's unpredictability, and proposes potential solutions. These insights aim to establish a more standardized and universally applicable approach for investigating kidney fibrosis.
Introduction
Chronic kidney disease (CKD) affects over 10% of the global population, and its prevalence is increasing1. Various urinary tract conditions, including congenital anatomical anomalies, nephrolithiasis, prostatic hyperplasia, and bladder tumors, can lead to ureteral obstruction². As a result, the unilateral ureteral obstruction (UUO) mouse model is a key tool for identifying new mechanisms of kidney interstitial fibrosis, understanding disease progression, and evaluating potential treatment strategies. It has been widely used to investigate the origin of myofibroblasts, (myo)fibroblast subclusters, tubular cell metabolism, and cell cycle arr....
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Protocol
All animal procedures are conducted in accordance with agency guidelines and approved by the Institutional Animal Ethics Committee of Nanjing Medical University. To eliminate sex and strain differences and ensure comparability of results, only male CD1 mice aged 8-10 weeks and weighing 22-25 g are used. The details of the reagents and equipment used in this study are listed in the Table of Materials.
1. Animal and instrument preparation
- Autoclave all surgical instruments before surgery.
- Weigh and anesthetize the mice (following institutionally approved protocols). Properly connect the ....
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Results
Histology
Periodic acid-Schiff (PAS) staining revealed tubular dilation, loss of brush borders, cast formation, and tubular epithelial swelling. Masson's trichrome and Sirius red staining showed interstitial fibrosis following UUO, in contrast to the normal compact tubules with discernible lumens observed in the sham group. The degree of renal interstitial fibrosis, indicated by blue areas in Masson's trichrome staining and red areas in Sirius red staining, increased in a time-dependent manner (
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Discussion
A comprehensive procedure for establishing the UUO model, a widely used approach for investigating kidney interstitial fibrosis, is provided. Additionally, the identification and assessment of the model, including evaluations of renal function and histological alterations, are demonstrated. The variables contributing to the model's heterogeneity and modifiable technical factors are discussed.
Susceptibility to UUO varies significantly based on age, sex, and mouse strain. Compared to C57BL/6 mi.......
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Disclosures
The authors declare no conflict of interest.
Acknowledgements
This work was supported by National Science Foundation of China Grants (82370686/2024YFA1107704), Jiangsu Specially-Appointed Professor Grant, Nanjing Science and Technology Innovation Project, Jiangsu Province Hospital High-level Talent Cultivation Program (Phase I) (CZ0121002010037), Natural Science Foundation of Jiangsu Province (BK20240055), and Jiangsu Medical Innovation Team to JR; Jiangsu Province Hospital (the First Affiliated Hospital with Nanjing Medical University) Clinical Capacity Enhancement Project (JSPH-MA-2023-4), Priority Academic Program Development of Jiangsu Higher Education Institutions (China) and National Natural Science Foundation of China (81....
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| 1 mL Syringe | Mingankang | / | |
| 4/0 surgical suture | Jinhuan Medical | F401 | |
| 75% Ethanol | Lircon | 6303060031 | |
| Anesthesia Air Pump | RWD Life Science | R510-29 | |
| Anesthesia Induction Chambers | RWD Life Science | V102-V | |
| Animal hair clipper | Jinke | / | |
| Betadine solution | Lircon | 6303030036 | |
| Buprenorphine (analgesic) | RWD Life Science | / | |
| Curved iris forceps | jinke | / | |
| Electronic heat pad | Reptizoo | AHM23 | |
| fine straight forceps | Jinke | / | |
| Gas Filter Canister | RWD Life Science | R510-31-6 | |
| Gauze Pads | Winner Medical | 601-026576 | |
| Iris Scissors | Jinke | / | |
| Isoflurane (anesthetic) | RWD Life Science | R510-22-10 | |
| Multi-output Animal Anesthesia Machine | RWD Life Science | R550IE | |
| Needle holder | jinke | / | |
| Ophthalmic ointment | Dechra NDC | 17033-211-38 | |
| Sterile Cotton swab | Winner Medical | 601-015213 | |
| Sterile saline | Shimen | H20066533 |
References
- Bello, A. K., et al. An update on the global disparities in kidney disease burden and care across world countries and regions. Lancet Glob Health. 12 (3), e382-e395 (2024).
- Klahr, S. Obstructive nephropathy. Intern Med. 39 (5), 355-361 (2000).
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