Wound healing in foetal sheep: a histological and electron microscope study

Area of Science:

• Developmental biology
• Wound healing research
• Comparative pathology

Background:

• Skin wound healing mechanisms are crucial for tissue repair.
• Understanding fetal healing provides insights into regenerative processes.
• Sheep models offer valuable comparative anatomy for human studies.

Purpose of the Study:

• To investigate fetal sheep skin wound healing across different gestational ages.
• To compare fetal wound healing with that of newborn and adult sheep.
• To characterize the inflammatory and cellular responses during fetal wound repair.

Main Methods:

• Excised, unsutured, and sutured skin wounds were created in fetal sheep (75, 90, 120 days gestation), newborn lambs, and adult ewes.
• Histological and electron microscopy were used to examine granulation tissue formation and scar maturation.
• Polyvinyl sponges were implanted subcutaneously to assess vascularized scar tissue formation.
• Cellular inflammatory responses were evaluated by analyzing extravascular cell types and numbers.

Main Results:

• Fetal and postnatal wounds exhibited similar healing patterns, including rapid contraction and scar formation.
• Histological analysis confirmed granulation tissue development and maturation into scar tissue in all wound types.
• Fetal sheep demonstrated the capacity to form vascularized scar tissue, confirmed by sponge implantation.
• The cellular inflammatory response was significantly less prominent in fetal sheep compared to postnatal animals.
• Fetal sheep exhibited early reactivity to irritants, forming multinucleate giant cells.

Conclusions:

• Fetal sheep skin wounds heal effectively, mirroring postnatal healing processes.
• The reduced inflammatory response in fetal wounds may contribute to scarless healing.
• Fetal wound healing mechanisms offer potential insights for regenerative medicine and therapeutic strategies.