Dietary phosphorus restriction enables multigenerational breeding of α-Klotho-deficient rats

Severe -Klotho deficiency in rats leads to early mortality and reproductive issues, making it challenging to maintain and analyze these models over generations. Researchers created rats with a CRISPR/Cas9-mediated deletion of -Klotho in the exons 1-5 region and tested the effects of dietary phosphorus restriction. They found that restricting maternal phosphorus intake during mating and lactation resulted in higher overall survival to weaning (92.6% vs. 85.8%) and a greater proportion of -Klotho-deficient offspring (34/113 vs. 23/145).

Additionally, limiting phosphorus intake post-weaning helped maintain growth, gonadal development, and natural breeding among -Klotho-deficient rats. After 15 litters, 74 out of 85 offspring survived to weaning, allowing researchers to sustain -Klotho-deficient colonies for at least five generations. The study also examined 24-hour metabolic rhythms in phosphorus-restricted -Klotho-deficient rats, which showed variability under a light-dark cycle.

Overall, dietary phosphorus restriction proved to be an effective method for maintaining multigenerational severe -Klotho-deficient rat models, creating a sustainable platform for investigating residual metabolic and physiological traits.