Advanced oxidation protein products accelerate bone deterioration in aged rats

Area of Science:

• Biochemistry
• Gerontology
• Orthopedics

Background:

• Advanced oxidation protein products (AOPPs) are markers of protein damage.
• AOPP accumulation is implicated in various diseases.
• Previous studies linked AOPPs to reduced bone mineral density and impaired osteoblast function.

Purpose of the Study:

• To investigate if AOPPs accelerate bone deterioration in aged rats.
• To test the hypothesis that AOPP accumulation contributes to senile osteoporosis.

Main Methods:

• 18-month-old male Sprague Dawley rats received intravenous injections of vehicle, native rat serum albumin (RSA), or AOPPs-modified RSA (AOPPs-RSA).
• Some groups also received oral apocynin, a NADPH oxidase inhibitor.
• Bone mineral density, micro-CT imaging, and bone biomarkers were analyzed after 8 or 16 weeks.

Main Results:

• AOPPs-RSA treatment significantly decreased vertebral bone mineral density and worsened bone microstructure in tibias and lumbar vertebrae.
• These changes were associated with altered plasma levels of bone biomarkers (decreased bone-specific alkaline phosphatase, increased tartrate-resistant acid phosphatase 5b).
• Apocynin administration prevented AOPP-induced bone deterioration.

Conclusions:

• AOPP accumulation accelerates bone deterioration in aged rats, suggesting a role in senile osteoporosis.
• The protective effect of apocynin indicates that NADPH oxidase activation is involved in AOPP-induced bone damage.
• These findings offer insights into osteoporosis pathogenesis and potential therapeutic strategies.