ABSTRACT
Objective To explore the proliferative changes and clinical significance of osteoclasts (OC) in various stages of osteoarthritis (OA). Methods Twenty healthy adult male SD rats were made the model by modified Hulht procedure,the left knee served as the control group and the right knee as the OA model group. The total knee joint (n=5) was collected at postoperative 1, 2,4,8 weeks, fixed at 4 ℃ 4% poly formaldehyde (PFA) liquid, embedded by paraffin for conducting sections, and stained by TRAP,toluidine blue(TB) and safranine O (Saf O)fast staining. Then the cartilage morphology change was observed and OC positive cells number with TRAP staining were semi-quantitatively detected,the OA cartilage destruction progression was evaluated by Mankin's method and SPSS17.0 statistics software was used to conduct statistical analysis. Results OC in the two groups showed the transient change of rapidly increasing and then decreasing. The OC number at 1 week in the control group (left knee) was (65.20±4.12) cells/mm2 ,and was gradually reduced at 2,4 weeks,which were (47.20±4.31) cells/mm and (26.20±3. 87) cells/mm2 ,which at 8 weeks was almost invisible, the number of cells was (7.00 ± 2.28) cells/mm2 ;the OC number at 1 week in the OA model group (right knee) was (70.40 ± 5.46) cells/mm2 ,increased to (86.20± 5.42)cells /mm2 at 2 weeks, reduced to (38. 0 ± 3.16) cells/mm2 at 4 weeks , was almost invisible at 8 weeks, the number of cells was (6.21 ± 2.93 ) cells/mm2 . The OC number at 2,4 weeks in the model group was significantly higher than that in the control group, the difference had statistical significance (P<0.05). Conclusion Large numbers of osteoclasts are proliferated in the early and middle stages of rat knee osteoarthritis, which indicating that OC might be involved in the formation of osteoarthritis.
ABSTRACT
Objective To establish the animal model of traumatic myositis ossificans through striking the quadriceps muscle of rabbits repeatedly.Methods Nine white adult New Zealand rabbits were selected,as their left lower limbs were used as the model group and the right lower ones served as controls.The left hind limbs were stricken by a 0.25 kg ball falling from a height of 100 cm every 3 days for and then immobilized with the knee in extension,while the right knees were immobilized in the same way without striking.The rabbits were sacrificed at the 4th,6th and 8th weeks respectively.The swelling,local physical signs and pathological changes of the heterotopic ossification had been assessed.Results The swelling of left quadriceps was obvious,with progressively stiffness of the left knees accompanied by distinctly palpable indurations,while in the right hind limbs,the joint was stiff but without indurations.The imaging examination showed the ossification began to appear in the impact sites of the model group at the 4th,6th and 8th weeks.The hematoxylin-eosin staining demonstrated that there was obvious cartilage or bone formation in the muscle tissues of the left quadriceps at the 8th weeks.Conclusion An animal model of post-traumatic myositis ossificans can be successfully established in rabbits through beating their quadriceps repeatedly.
ABSTRACT
The technique of double-layered plate was developed for screening the library of mutant endoglucanase III from Trichoderma reesei generated by the method of directed evolution.The enzyme activity was determined according to the velocity of the formation of halos on the plates.Several mutants with higher activity than the wild type at low temperature or alkaline pH were obtained by using this strategy under different screening conditions.Further results of spectrophotometric determination of the activities of these mutants were consistent with the results of plate screening.The establishment of such strategy will broaden the applications of the directed evolution methods for improving the existing proteins to obtain useful enzymes with new properties for industrial applications.