Establishment of Rat Model of Acute Antibody-Mediated Rejection in Kidney Transplantation

Summary

This article describes the establishment of a rat model of acute antibody-mediated rejection (AAMR) in kidney transplantation. The model is induced by presensitizing recipient Lewis rats with skin grafts from donor Brown Norway rats 14 days prior to kidney transplantation, providing a robust platform for studying AAMR pathophysiology.

Abstract

Acute antibody-mediated rejection (AAMR) remains a major obstacle to long-term graft survival in kidney transplantation. The pathophysiology of AAMR is primarily driven by donor-specific antibodies (DSA) that trigger complement activation, leading to endothelial cell injury, vasculitis, and graft dysfunction. Despite advancements in immunosuppressive therapies, the treatment of AAMR remains suboptimal. Therefore, the development of reliable animal models for AAMR is crucial for understanding its mechanisms and evaluating potential therapeutic interventions. In this study, a rat model of AAMR was established by sensitizing recipient Lewis rats with donor Brown Norway rat skin grafts for 14 days prior to kidney transplantation. No immunosuppressive agents were administered to the recipients throughout the study. Survival analysis demonstrated significantly reduced graft survival in the presensitized allogeneic group compared with the non-presensitized group (6.2 ± 1.1 d vs 10.0 ± 0.7 d, P < 0.001). The levels of serum DSA-IgG significantly increased from the 7th day after skin transplantation and continued to rise until the 5th day after kidney transplantation, and the levels of serum DSA-IgM significantly increased on the 7th and 14th days after skin transplantation. Starting 6 h after kidney transplantation, the allografts began to show signs of glomerulitis, peritubular capillaritis, and C4d deposition in capillaries. Starting from 3 days after kidney transplantation, significant allograft damage and tubular necrosis were observed. These changes gradually worsened over time and are all consistent with the characteristics of AAMR. This model effectively recapitulates the key features of AAMR, providing a robust platform for future studies on underlying mechanisms and potential treatments.

Introduction

Kidney transplantation (KT) has become a critical therapeutic approach for end-stage renal disease^1,2. However, transplant rejection remains a major factor affecting the long-term survival of renal allografts^3,4. The primary types of rejection observed clinically are acute rejection (AR) and chronic rejection (CR). Acute rejection is further classified into acute T cell-mediated rejection (TCMR) and acute antibody-mediated rejection (AAMR)^5,6,7. In recent year....

Protocol

All animal procedures were conducted in strict compliance with institutional guidelines and approved by the Institutional Animal Ethics Committee of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital. All procedures adhered to the 3R principle and the Declaration of Helsinki (Approval No. JENNIO-IACUC-2024-A066). The reagents and equipment used in this study are detailed in the Table of Materials.

1. Animal preparation

1. House adult male BN (RT1ⁿ) and Lewis (RT1^l) rats (200-250 g) in specific pathogen-free (SPF) facilities. As inbred strains, indi....

Results

Renal allograft survival time
Recipients in both the syngeneic KT and the syngeneic KT after ST groups survived long-term without rejection throughout the one-month observation period. Conversely, the survival time of allografts in the allogeneic KT group and the allogeneic KT after ST group was (10.0 ± 0.7) days and (6.2 ± 1.1) days, respectively, with a statistically significant difference between the two groups (Figure 2A).

Levels o.......

Discussion

AAMR remains a significant challenge in KT due to its rapid progression and unfavorable clinical outcomes^33,34,35,36. Even with effective current anti-rejection treatments reversing acute episodes, more than 40% of patients advance to chronic AMR. After a chronic AMR diagnosis, the five-year graft survival rate often drops below 50%. The 4-year graft survival rate in C4d-positive patients is on.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anti-CD31 Monoclonal Antibody	Abcam (UK)	ab64543	For immunohistochemistry (labeling vascular endothelial cells) Clone number: TLD-3A12
Anti-C4d  Antibody	Hycult Biotech (Netherlands)	HP8034	For immunohistochemistry (detecting complement deposition), dilution is 1:50 Clone number: NA (Polyclonal)
FITC-Conjugated Anti-Rat IgG Antibody	Abcam (UK)	ab6840	Used for flow cytometric quantification of DSA-IgG levels Clone number: Polyclonal
Gas Anesthesia System	Nanjing Calvin Biotechnology Co., Ltd.	KW-MZJ-4	Equipped with isoflurane for general anesthesia Clone number: NA (Polyclonal)
PE-Conjugated Anti-Rat IgM Antibody	Bio Legend	408918	Used for flow cytometric quantification of DSA-IgM levels Clone number: MRM-47
Stereotaxic Surgical Microscope	Beijing Zhongtian Guangzheng Technology Co., Ltd.	TS-39NK	Used for performing rat renal transplantation surgery Clone number: NA
Vascular Bulldog Clamps	ROBOZ SURGICAL INSTRUMENT CO.	RS-5481T	Used to block blood flow during renal transplantation Clone number: NA