Platelet rich plasma associated with heterologous fresh and thawed chondrocytes on osteochondral lesions of rabbits / Associação de plasma rico em plaquetas e condrócitos heterólogos frescos e descongelados em lesão osteocondral de coelhos

Chondrocytes obtained from stifle joint of New Zealand White rabbits were cultivated. Half of cells were maintained in culture for later implantation and the others frozen during six months to evaluate viability. A circular osteochondral defect was created in the right stifle of other twenty seven rabbits. The control group (CG) received no treatment. The thawed (TH) and fresh (FH) heterologous groups received, respectively, an implant of cultivated thawed or fresh heterologous chondrocytes associated with platelet rich plasma (PRP). The CG group showed greatest pain and lameness compared to the other groups seven days after the implantation. Microscopically, at 45 and 90 days, the TH and FH groups showed filling with cartilaginous tissue containing chondrocytes surrounded by a dense matrix of glycosaminoglycans. In the CG group, healing occurred with vascularized fibrous connective tissue without integration to the subchondral bone. Cryopreserved heterologous chondrocytes were viable for implantation and healing of osteochondral lesions; the association with PRP allows the fixation of cells in the lesion and offers growth factors which accelerates repair with tissue similar to articular hyaline cartilage.

Cultivaram-se condrócitos obtidos da articulação do joelho de coelhos. Metade das células foi mantida em cultura para posterior implantação, e a outra metade foi congelada durante seis meses com a finalidade de avaliar a viabilidade. Criou-se um defeito circular osteocondral no joelho direito de outros vinte e sete coelhos. O grupo controle (GC) não recebeu tratamento. Os grupos descongelado (TH) e fresco (FH) receberam, respectivamente, implantes heterólogos de condrócitos cultivados descongelados e frescos, associados com PRP. O grupo GC apresentou maior dor e claudicação em comparação com os outros grupos aos sete dias após o implante. Microscopicamente, aos 45 e 90 dias, os grupos TH e FH mostraram preenchimento da falha com tecido cartilaginoso contendo condrócitos circundados por uma matriz densa de glicosaminoglicanos. Nesse período, no grupo CG, a cura ocorreu com tecido conjuntivo fibroso vascularizado e sem integração com o osso subcondral. Condrócitos heterólogos criopreservados foram viáveis para implantação e tratamento de lesões osteocondrais; a associação com o PRP permitiu a fixação de células na lesão e ofereceu fatores de crescimento que aceleraram a reparação com o tecido semelhante à cartilagem hialina articular.

Functional and ultrastructural evaluation of myocardial protection provided by intermittent coronary sinus perfusion in the isolated dog heart

The protection offered by intermittent perfusion of cardioplegic solution through the coronary sinus was investigated in isovolumic blood-perfused dog heart preparations submitted to 60 min of ischemia and 45 min of reperfusion. The prepations were divided into three treatment groups: a) coronary sinus, consisting of preparations (N=10) perfused through the coronary sinus under 40 cm water pressure: b) aortic, consisting of preparations (N=10) perfused through the aortic stump under 100 mm Hg pressure; c) control,consisting of hearts (N=9) that were not perfused with cardioplegic solution. Properties of contractile capacity and relaxation were markedly impaired in the control group but were preserved to a comparable extent in the groups perfused with cardioplegic solution through the aorta and coronary sinus. Developed pressure decreased in the control group (before ischemia: 70 ñ 5.5 mmHg; after reperfusion: 35 ñ 12 mmHg; P,0.05) and didn't vary in the aortic group (from 69 ñ 4mmHg to 65 ñ 13 mmHg: P>0.05) and coronary sinus group (from 69 ñ 4.6 mmHg to 60 ñ 10 mmHg; P>0.05). Myocardial relaxation was evaluated by the +/-dp/dt ratio. In the control group there was impairment of myocardial relation as indicated by an increase of this index after reperfusion (from 1.05 ñ 0.05 to 1.46 ñ 0.23; P<0.05), whereas in the aortic (from 1.10 ñ 0.13 to 1.15 ñ 0.20; P>0.05) and the coronary sinus (from 1.03 ñ 0.14 to 1.08 ñ 0.16; P>0.05) groups there was no variation. Ultrastructural changes in the myocardium were negligible in all three groups at the end of reperfusion. We conclude that intermittent perfusion of a hypothermic cardioplegic solution through the coronary sinus is effective for the protection of the myocardium during total ischemia