Experimental Study On Blood-induced Damage To Articular Cartilage In Vivo

Objective: The purpose of this study is to explore theblood-induced damage to articular cartilage and to treat jointbleeding rationally. Joint bleeding is very common in traumaticinjury. Articular cartilage is temporarily immersed in blood.Doctors often take conservative methods to treat this condition.Therefore blood is totally absorbed. But it increase thepossibility of osteoarthritis (OA) characterized by cartilagedegeneration. In this study, fresh collected autologous blood wasinjected directly into the knees of the rabbits to simulate thepathologic process of joint bleeding. The main observationsinclude: gross appearance, light microscope (HE sections),water content, proteoglycan (PG) content and collagen content.Through these observations, the mechanism of articularcartilage damage and the relation between the changes and thetime can be explained. Methods: 36 rabbits were randomly divided into 2 groups,18 each namely group1 and group 2. In group 1, fresh collectedautologous blood (4ml) was injected into the right knee at 1 day.Contralateral (left) knee were not injected at all to act as control.The same volume of blood was injected in the same knee at day3. In group 2, 4ml and 2ml blood was injected into right knee 5英 文 摘 要and left knee respectively to observe the destruction propertiesof different amount of blood on cartilage. The other procedureswere the same as those in group 1. Each group was divided into3 sub-groups, 6 each. The animals of each sub-group weresacrificed at 1, 4 and 8 weeks respectively. Articular cartilagewas harvested at the middle point of medial femoral condyleand lateral femoral condyle, which is 2mm wide, 3mm to theedge of posterior femoral condyle. The tissue blocks were fixedin 10% neutral buffered formalin containing 1% cetylpridiniumchloride for 48 hours and were decalcified with EDTA to beused as forming sections (2 sections made for Safranin O stain).The rest articular cartilage was obtained from the femoralcondyle and tibial plateau in a close operation cabinet. Half wasused for water content, half for collagen content. Theobservations were as follows: (1) Water content: Articularcartilage was dried under vacuum circumstance with P2O5.Water content = (Wet Weight－Dry Weight) / Wet Weight ×100%. (2) PG content: According to Shin-Chieh Hung, cartilagewas divided into 3 layers – superficial layer, intermediate layerand deep layer. The microscope was attached to multifunctionalpathology analyzing system. Brightness was modulated andfixed to collect the images at the same standard. 6 Images wereobtained from 2 Safranin O-stained sections. Average lightdensity of every layer could be obtained, which represents PGcontent of corresponding cartilage layer. (3) Hydroxyprolinethat represents the collagen content of articular cartilage was 6英 文 摘 要calculated by chromatometry. Results: (1) Gross appearance: The articular cartilageaffected by blood was not smooth at all, which was rougher in4ml group than in 2ml group, especially in 1 week. (2) Lightmicroscope (HE): The articular cartilage of experimental sidebecame rough with more division cells. The tidemark becameunclear. All of these appearances were more apparent in 4mlgroup than in 2ml group. (3) Immunohistochemistry of collagentype Ⅱ : The most superficial layer of the cartilage ofexperimental side became lighter at 1 week, but the heavydomain around chondrocyte changed little. There were nochanges at 4 weeks and 8 weeks. (4) Water content: (ⅰ) Watercontent increased at 1 week and 4 weeks compared with thecontrol group(P<0.05). There were no differences of watercontent at 8 weeks (P>0.05). There was more decreased amountof water at 4 weeks than at 1 week (P<0.05), at 8 weeks than 4weeks (P<0.05). (ⅱ) The comparison between 4ml group and2ml group: There was an increase of water content of 4ml groupthan...