Genetic differences in C57BL/6 mouse substrains affect kidney crystal deposition

Area of Science:

• Nephrology
• Genetics
• Biochemistry

Background:

• Calcium oxalate crystal deposition in the kidney is a significant health concern.
• C57BL/6J (B6J) and C57BL/6N (B6N) are common mouse substrains with subtle genetic variations.
• Understanding genetic influences on kidney stone formation is crucial for developing targeted therapies.

Purpose of the Study:

• To compare kidney crystal formation between B6J and B6N mouse substrains.
• To investigate the role of genetic background in the pathogenesis of kidney stone formation.
• To identify specific genes and proteins associated with differential crystal deposition.

Main Methods:

• Establishment of a glyoxylate-induced kidney crystal deposition model in B6J and B6N mice.
• Quantitative polymerase chain reaction (qPCR) to assess gene expression levels.
• Western blotting and immunohistochemistry to evaluate protein expression and localization.

Main Results:

• B6J mice exhibited significantly higher kidney crystal deposition compared to B6N mice.
• The expression of nicotinamide nucleotide transhydrogenase (Nnt) gene was significantly lower in B6J mice.
• Nnt protein was detected in B6N mice, primarily in renal tubular epithelial cells, but absent in B6J mice.

Conclusions:

• Substrain differences in C57BL/6 mice significantly influence kidney crystal deposition.
• The absence of Nnt protein in B6J mice may play a critical role in promoting kidney stone formation.
• This study highlights the importance of genetic background in experimental models of nephrolithiasis.