Abstract
Objective: To determine the staining grades and morphological changes in the cells of articular cartilage of patella on immobilisation and re-mobilisation in rats.
Methods: A total of 120 Sprague Dawley rats were divided into four groups of 30 animals. The study was done between July and December 2009. Group I consisted of control animals that were not immobilised. Group 2 were immobilised for four weeks. Group 3 consisted of animals that were immobilised for four weeks and re-mobilised for four weeks. Group 4 consisted of animals that were immobilised for four weeks and re-mobilised for eight weeks. At the end of the period, the knee joint was dissected in sagittal plane along with patella. Tissue specimens were stored in 10% formalin for 48 hours. After processing for making paraffin blocks, 10 mu m and 7 mu m sections were cut from the same block and stained with Alcian Blue and Haematoxylin and Eosin stain.
Results: Extensive necrotic changes were observed on four weeks immobilisation. On four weeks re-mobilisation after four weeks of immobilization, the superficial zone was sloughed off, but on eight weeks re-mobilisation after four weeks of immobilization, regeneration was seen in the superficial zone. The superficial zone was affected both in immobilisation and re-mobilisation.
Conclusion: After eight weeks re-mobilisation, regeneration was still going on. No conclusion can be drawn regarding the exact time required for complete reversibility of the changes in the cartilage.