Ultrastructural identification of developing proximal tubules based on three-dimensional reconstruction

Area of Science:

• Nephrology
• Developmental Biology
• Cell Biology

Background:

• Proximal tubule development involves morphogenesis and adult tubule repair.
• Current knowledge of cell differentiation and proliferation in developing tubules is limited, hindering origin identification.

Purpose of the Study:

• To investigate the ultrastructural changes in proximal tubules during different stages of nephrogenesis.

Main Methods:

• Utilized electron microscopy for ultrastructural analysis.
• Employed computer-assisted tubular tracing to identify cellular structures.

Main Results:

• Early stages (renal vesicles, S-shaped bodies) showed proliferative cell features and protein-producing organelles.
• Capillary-loop stage tubules exhibited developing mature characteristics, including microvilli, lateral processes, basal infoldings, and mitochondrial density, alongside an established endocytic system.
• Observed distinct electron-dense and electron-lucent cells, indicative of active proliferation and differentiation.

Conclusions:

• Proximal tubule morphogenesis correlates with the progressive establishment of physiological functions.
• Variations in cellular electron density suggest distinct cell differentiation patterns within the developing tubule.