Embryonic and postnatal development of the rat renal interstitium

Area of Science:

• Nephrology
• Developmental Biology
• Cell Biology

Background:

• The role of renomedullary interstitial cells in adult kidney function is known, but their role in renal development is unclear.
• These cells are implicated in antihypertensive and structural roles in mature kidneys.

Purpose of the Study:

• To investigate the role of renomedullary interstitial cells during kidney development.
• To characterize the presence, arrangement, and interactions of these cells from embryonic to postnatal stages.

Main Methods:

• Studied rat kidneys from embryonic day 14 (E14) to postnatal day 28 (P28).
• Employed light microscopy, transmission electron microscopy, scanning electron microscopy, and immunocytochemistry.
• Examined cell morphology, arrangement, and interactions with developing renal structures.

Main Results:

• Renomedullary interstitial cells were identified as early as E14, forming networks around ureteric bud branches.
• Cells arranged concentrically around collecting ducts, creating a 'rungs of a ladder' appearance with tubules and blood vessels.
• These cells adhered to basement membranes of tubules, blood vessels, and collecting ducts, with specific laminin localization patterns observed.

Conclusions:

• Renomedullary interstitial cells are present early in renal development and actively participate in tubule repositioning.
• These cells are integral components of the developing renal medulla, contributing to its structural organization.