Abstract: This document provides methods and materials for treating aging and/or improving transplant outcomes. For example, methods and materials for using one or more senotherapeutic agents to reduce risk of transplant rejection are provided. Non-human animal models for transplant rejection as well as methods for using such non-human animal models to identify agents having the ability to reduce transplant rejection are provided as are non-human animal models for aging and methods for using such non-human animal models to identify agents having the ability to treat aging or the ability to slow the effects of aging.