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Published on: August 31, 2022
Ras associated with diabetes may play a role in fracture nonunion development in rats
Takahiro Oda, Takahiro Niikura1, Tomoaki Fukui2
1Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan. tniikura@med.kobe-u.ac.jp.
Background:
Rad is the prototypic member of a subfamily of Ras-related small G-proteins and is highly expressed in the skeletal muscle of patients with type II diabetes. Our previous microarray analysis suggested that Rad may mediate fracture nonunion development. Thus, the present study used rat experimental models to investigate and compare the gene and protein expression patterns of both Rad and Rem1, another RGK subfamily member, in nonunions and standard healing fractures.
Methods:
Standard healing fractures and nonunions (produced via periosteal cauterization at the fracture site) were created in the femurs of 3-month-old male Sprague-Dawley rats. At post-fracture days 7, 14, 21, and 28, the fracture callus and fibrous tissue from the standard healing fractures and nonunions, respectively, were harvested and screened (via real-time PCR) for Rad and Rem1 expression. The immunolocalization of both encoded proteins was analyzed at post-fracture days 14 and 21. At the same time points, hematoxylin and eosin staining was performed to identify the detailed tissue structures.
Results:
Results of real-time PCR analysis showed that Rad expression increased significantly in the nonunions, compared to that in the standard healing fractures, at post-fracture days 14, 21, and 28. Conversely, immunohistochemical analysis revealed the immunolocalization of Rad to be similar to that of Rem1 in both fracture types at post-fracture days 14 and 21.
Conclusions:
Rad may mediate nonunion development, and thus, may be a promising therapeutic target to treat these injuries.
Insights
Rad protein expression increases in fracture nonunions, suggesting it may drive nonunion development. This finding highlights Rad as a potential therapeutic target for fracture healing.
Area of Science:
- Biochemistry
- Molecular Biology
- Orthopedics
Background:
- Rad, a Ras-related small G-protein, is upregulated in skeletal muscle of type II diabetes patients.
- Previous studies suggest Rad's involvement in fracture nonunion development.
Purpose of the Study:
- To investigate and compare gene and protein expression of Rad and Rem1 in rat models of fracture nonunion and standard healing.
- To assess the role of Rad in mediating fracture nonunion.
Main Methods:
- Rat femur fracture models (standard healing vs. nonunion) were established.
- Real-time PCR and immunohistochemistry were used to analyze Rad and Rem1 expression at multiple time points post-fracture.
- Hematoxylin and eosin staining assessed tissue structures.
Main Results:
- Rad gene expression was significantly elevated in nonunions compared to standard healing fractures at days 14, 21, and 28.
- Rad protein immunolocalization patterns were similar to Rem1 in both fracture types at days 14 and 21.
Conclusions:
- Rad expression is upregulated in fracture nonunions.
- Rad may play a role in mediating nonunion development.
- Rad represents a potential therapeutic target for treating fracture nonunion injuries.
