Uterine collagen during pregnancy in cattle

Area of Science:

• Reproductive biology
• Veterinary medicine
• Biochemistry

Background:

• The bovine uterus undergoes significant physiological changes during pregnancy.
• Understanding uterine remodeling is crucial for reproductive health and productivity in dairy cattle.

Purpose of the Study:

• To investigate the changes in uterine weight, collagen content, and collagen cross-linking during dairy cattle gestation.
• To quantify the specific collagen cross-link, pyridinoline, throughout pregnancy.

Main Methods:

• Collection of uteri from non-pregnant and pregnant dairy cattle at various gestational stages.
• Measurement of whole uterus and uterine horn weights.
• Analysis of total collagen content and collagen concentration.
• Identification and quantification of the collagen cross-link, pyridinoline.

Main Results:

• Whole uterus weight increased approximately 12-fold during the 9-month gestation period.
• The pregnant uterine horn showed the most significant weight increase.
• Increased uterine horn weight correlated with increased total collagen content, while collagen concentration remained constant.
• Pyridinoline was identified in pregnant uterine tissues at a consistent level of ~0.13 residues per mole of collagen from early to late gestation.

Conclusions:

• Bovine uterine expansion during pregnancy involves a substantial increase in overall collagen mass, not concentration.
• The collagen cross-link pyridinoline is present at a stable level throughout gestation, suggesting its structural role is maintained.
• These findings provide insights into the biomechanical adaptations of the bovine uterus during pregnancy.