[P3-0806] Knee joint stability reduces the expression of caspase-3 mRNA after anterior cruciate ligament injury in a rat model
Keywords:apoptosis, Knee joint stability, anterior cruciate ligament injury
【Purpose】
The anterior cruciate ligament（ACL）of the knee plays an important role in controlling and stabilizing the knee joint.
ACL is very frequently injured.
After injury, the nuclear intrinsic factors which are involved in apoptosis, such as TNF-α, MMPs, and caspases, are associated with the degeneration of ACL.
Caspases are particularly importamt apoptosis effectors for removal of abnormal cells.
The purpose of this study was to investigate the influence of caspases on ACL after injury.
【Methods】
Thirty-six 10-week-old male Wistar rats were divided into three groups of 12 rats each：ACL transection（ACL-T）, ACL transection and surgery for joint stability（JC）, and sham operated（Sham）.
After the surgery, six rats each per group were sacrificed at 2 and 4 weeks.
Total RNA was collected from ACL to determine the relative expression levels of caspase-3 mRNA using real-time PCR.
These data were analyzed using the one-way ANOVA test with the Bonferroni method for multiple comparisons.
【Results】
At 2weeks, the expression of caspase-3 mRNA was 40.0-fold higher in the ACL-T group and 30.0-fold higher in the JC group than the Sham group, which was statistically significant（p＜0.05）.
At 4 weeks, the expression of caspase-3 mRNA was 43-fold higher in the ACL-T group and 6-fold higher in the JC group than in the Sham group.
In 4weeks, however, there is no statistically significant change in among group.
【Discussion】
Our results indicate that the expression of caspase-3 mRNA decreases with controlled joint movement.
A previous study has reported an increased number of undifferentiated cells associated with ACL fibers in rats with controlled joint movements（Kokubun T, 2011）.
Thus, our study provides evidence that the expression of caspase helps maintain homeostasis in cells and/or is associated with the degeneration of ACL.
The anterior cruciate ligament（ACL）of the knee plays an important role in controlling and stabilizing the knee joint.
ACL is very frequently injured.
After injury, the nuclear intrinsic factors which are involved in apoptosis, such as TNF-α, MMPs, and caspases, are associated with the degeneration of ACL.
Caspases are particularly importamt apoptosis effectors for removal of abnormal cells.
The purpose of this study was to investigate the influence of caspases on ACL after injury.
【Methods】
Thirty-six 10-week-old male Wistar rats were divided into three groups of 12 rats each：ACL transection（ACL-T）, ACL transection and surgery for joint stability（JC）, and sham operated（Sham）.
After the surgery, six rats each per group were sacrificed at 2 and 4 weeks.
Total RNA was collected from ACL to determine the relative expression levels of caspase-3 mRNA using real-time PCR.
These data were analyzed using the one-way ANOVA test with the Bonferroni method for multiple comparisons.
【Results】
At 2weeks, the expression of caspase-3 mRNA was 40.0-fold higher in the ACL-T group and 30.0-fold higher in the JC group than the Sham group, which was statistically significant（p＜0.05）.
At 4 weeks, the expression of caspase-3 mRNA was 43-fold higher in the ACL-T group and 6-fold higher in the JC group than in the Sham group.
In 4weeks, however, there is no statistically significant change in among group.
【Discussion】
Our results indicate that the expression of caspase-3 mRNA decreases with controlled joint movement.
A previous study has reported an increased number of undifferentiated cells associated with ACL fibers in rats with controlled joint movements（Kokubun T, 2011）.
Thus, our study provides evidence that the expression of caspase helps maintain homeostasis in cells and/or is associated with the degeneration of ACL.