| Background:Knee osteoarthritis (knee osteoarthritis, KOA) is the most common degenerative disease in the old people, The common symptoms include joint pain, hyperplasia of osteophyte, varus deformity for limbs. Lots of factors such as overweight, trauma, strenuous exercise are related to KOA. The early pathological changes lie in articular cartilage and subchondral bone degeneration. The joint cartilage with the blood vessels are found in patients with osteoarthritis Endochondral angiogenesis are regulated by a variety of factors. Cartilage degeneration and cartilage matrix mineralization are connected with this progress. Mechanism of angiogenesis in osteoarthritis is unclear and a variety of regulatory factors and molecular biology needs further research. The problem is the lack of specific and visualized methods in observing microvessels of joints. Based on microscopic CT examination with knee osteoarthritis (OA) of rats in different periods of cartilage and subchondral bone hyperplasia of blood vessels growth. This study has a purpose of observing different stages and different parts of the blood vessel growth change in osteoarthritis further clarifying the cartilage vascular invasion mechanism and exploring the pathogenesis of arthritis mechanism and the relationship between the pain, inflammation, and blood vessels.Method:(1)20 SD rats (male and female unlimited weight about 300 g) were randomly divided into experimental group (16)and the Sham group (4) according to computer. Experimental group are operated on left knee anterior cruciate ligament resection and left knee meniscus excision. SHAM group are operated on opening the joint capsule without removal of the anterior cruciate ligament and meniscus. The nano barium sulfate with gelatin in 65℃-70℃ water bath pot configured to contrast agent. The rat abdominal aorta are for injection segment and inferior vena cava are for the outflow segment, lower limb blood are replaced by heparinization saline. Formaldehyde solution are used for fixing perfused contrast agent. Fixed Specimens are frozen at night after death. Specimens are anatomized and taken out tibial plateau, for observing the microvascular perfusion with microscopic CT scan in the next day. The specimens are taken from experimental group in 3 weeks,6 weeks,9 weeks, and 12 weeks after operation. Based site is located in the lateral tibia bone and cartilage units. Methods of measurement include gross observation, histological grading, MircoCT vascular morphology metrology analysis, the three dimensional reconstruction of hyperplasia of blood vessels and vascular proliferation related genes of PCR detection, VEGF immunohistochemical staining (3) 50 cases tibial plateau of OA patients were gathered after total knee replacement from May 2013 to May 2014. The specimens were saved at-20℃ and all of patients have signed voluntary donation agreements according to the Outbridge classifications of OA cartilage specimens were divided into 4 groups:group A (level I),group B (level II), group C(level III) and group D (level IV). VEGF immunohistochemical staining,tissue staining and PCR gene amplification were used for detecting angiogenesis.Results:(1) microscopic CT showed that contrast is full of capillaries of the femoral condyle and tibia platform and the enhancement effect is good. Tibial plateau had cartilage degeneration in 3 week after removing the anterior cruciate ligament and meniscus. Arthritis disease became worse over time and classified according to the general observation and histological grading:Postoperative 3weeks:dot articular cartilage injury. Postoperative 6weeks:plate shaped articular cartilage degeneration, damage increased. Postoperative 9weeks:a full-thickness articular cartilage defects. Postoperative 12weeks:osteophyte formation. Tibial plateau and femoral condyle were analyzed through micro CT scan and make a proliferation of micro vessels by setting a threshold. The differences of micro vessels between surgery group and other groups were statistically significant (P< 0.05), amounts of micro vessels were relevance to the time change, the trend is that increased at first and decreased in the end. Angiogenesis reached a peak at 9 weeks postoperatively. (2) the specimens of group C has the highest positive rate of VEGF immunohistochemical staining in four groups(P<0.05). VEGF gene amplification detection related to angiogenesis in group C is higher than other groups(P<0.05).Conclusion:(1) The ratio of gelatin barium sulfate can be fully filled with vascular perfusion in rats, Microscopic CT can display capillaries within the joints with qualitative and quantitative analysis.In osteoarthritis rats model, hyperplasia of capillaries is relevance to the time change, increased first, then decreased, in the middle of the arthritis, proliferation of micro vessels reached peak. (2) Angiogenesis is crucial in the mechanism of the osteoarthritis. The proliferation of blood vessels in cartilage increased as arthritis symptoms worsen in the early stage of disease. Blood vessel growth slowed down with full-thickness cartilage defects, osteophyte formation in the late stage. |
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