Strain history and TGF-β1 induce urinary bladder wall smooth muscle remodeling and elastogenesis

Biomech Model Mechanobiol, 2012 · DOI: 10.1007/s10237-011-0298-y · Published: January 1, 2012

Urology Cardiovascular Science Biomechanics

Simple Explanation

This study investigates how mechanical forces and a growth factor called TGF-β1 affect the remodeling of the urinary bladder wall's smooth muscle. The researchers used an ex vivo system to stretch bladder tissue and found that a specific stretching pattern led to the production of elastin and changes in cell behavior. Adding TGF-β1 further altered the cell behavior and increased collagen production, suggesting its role in bladder wall changes seen in conditions like spinal cord injury.

Study Duration

7 days

Participants

Female Sprague–Dawley rats (aged 2–3 months, 150–300 g)

Evidence Level

Ex vivo organ culture

Key Findings

1
A 0.5-Hz strain frequency triangular waveform stimulation at 15% strain resulted in fibrillar elastin production, collagen turnover, and a more compliant ECM.
2
TGF-β1 increased soluble collagen production in the cultured bladders.
3
Culture of bladder strips at 0.5 Hz, 20% for 7 days mimicked the phenotype of the BSMC that was seen in the SCI bladders at 10 days.

Research Summary

This study examined the impact of mechanical strain and TGF-β1 on urinary bladder wall smooth muscle remodeling using an ex vivo organ culture system. Results showed that a 0.5-Hz strain induced elastogenesis and collagen turnover, leading to increased tissue compliance, similar to early changes observed in spinal cord injury bladders. The addition of TGF-β1 further altered cell phenotype and increased collagen production, suggesting a role in the fibrotic processes seen in later stages of bladder pathologies.

Practical Implications

Understanding Bladder Remodeling

Provides insights into the mechanisms driving bladder wall remodeling in response to mechanical and biochemical stimuli.

Potential Therapeutic Targets

Identifies potential targets for therapeutic interventions to prevent or reverse pathological bladder remodeling following SCI.

Ex Vivo Model for Research

Establishes an ex vivo model for studying ECM remodeling and cellular phenotypic shifts in bladder smooth muscle.

Study Limitations

1
Fetal bovine serum (10%) was used in order to maintain cell survival in the organ culture strips.
2
Cultures of the bladder strips were only carried out to 7 days due to a trend toward migration of the BSMC out of the tissue seen at later time points.
3
The lack of urothelium in our culture model may have also impacted our results.

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