To investigate the combined effect of bilateral ovariectomy (OVX) and anterior cruciate ligament transection (ACLT) with medial meniscectomy (MM) on the development of osteoarthritis (OA).
Twenty female 15-week-old Sprague-Dawley rats were used. Five rats in each group underwent bilateral OVX (OVX group), bilateral ACLT with MM (ACLT with MM group), bilateral OVX plus ACLT with MM (OVX plus ACLT with MM group), and sham surgery (SHAM group). All the rats were subjected to treadmill running for 4 weeks. The behavioral evaluation for induction of OA used the number of rears method, and this was conducted at 1, 2, and 4 weeks post-surgery. Bone mineral density (BMD) was calculated with micro-computerized tomography images and the modified Mankin's scoring was used for the histological changes.
The number of rears in the OVX plus ACLT with MM group decreased gradually and more rapidly in the ACLT with MM group. Histologically, the OVX plus ACLT with MM group had a significantly higher modified Mankin's score than the OVX group (p=0.008) and the SHAM group (p=0.008). BMDs of the OVX plus ACLT with MM group were significantly lower than the SHAM group (p=0.002), and the ACLT with MM group (p=0.003).
We found that bilateral OVX plus ACLT with MM induced definite OA change in terms of histology and BMD compared to bilateral OVX and ACLT with MM alone. Therefore, OVX and ACLT with MM was an appropriate degenerative OA rat model.
Citations
Method: Buffered saline at pH 4, 6 or 7.2 were injected twice, 3 days apart, into the gastrocnemius muscles of thirty Sprague-Dawley rats. To quantify hyperalgesia, paw withdrawal response to von Frey filament (mechanical hyperalgesia) and acetone (cold hyperalgesia) were measured for the 4 weeks after injection. Also the locomotor performance with inclined plane board and treadmill, and electrophys iologic study were evaluated.
Results: Mechanical hyperalgesia that was produced by the single injection of saline lasted less than 24 hours. The repeated injection of acidic saline produced mechanical hyperalgesia for more than 4 weeks at injected side and 3 weeks at contralateral side. Cold hyperalgesia lasted for 1 week after injection bilaterally. The locomotor performance and nerve conduction studies were not changed after injec tion.
Conclusion: We have developed and characterized a model of muscular pain that was long lasting and widespread. This might prove useful for studying pain of muscular origin that may be similar to the chronic pain syndromes observed clinically.
Objective: The purpose of this study is to determine neurotrophin effect in Fe-induced experimental spinal cord injury in adult female rat.
Method: Thirty Long-Evans rats (weight, 250 to 300 gr) were divided into 6 groups. Group I was control group. Group II was Fe-only group. Group III was NGF-only group. Group IV was NGF-Fe group. Group V was NT4-only group. Group VI was NT4-Fe group. For all experimental animals spinal cord was exposed by T10 laminectomy. Neurtrophin and Fe was injected at spinal cord directly by glass needle with ∼100 um diameter mounted on Hamilton syringe. Animals were sacrificed, spinal cord was extracted and prepared in sagittal section. Tissues were stained with LFB, NeuN and APC staining method. The amount of spinal cord damage was measured at 3 different locations under the microscope.
Results: Fe-only group showed more damage than the control group. NGF-only group showed the same result as the control group. NT4-only group showed more damage than the control group in LFB staining. NGF-Fe group showed the same result as Fe-only group. NT4-Fe group showed more damage than Fe-only group.
Conclusion: NGF has no additional effect, but NT4 potentiated Fe toxicity in Fe-induced experimental spinal cord injury. NT4 seems to be toxic to rat spinal cord in high dose.
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