( ( ( Recent studies ) ( ( using ( ( human ( recombinant BMP-2 ) ) ( in ( cell-free ( collagen sponges ) ) ) ) ) ( to ( ( heal ( articular ( cartilage defects ) ) ) ( in rabbits ) ) ) ) ) ( ( ( demonstrated ( repair tissue ) ) ( ( containing ( ( type ( II collagen ) ) ( at ( 24 weeks ) ) ) ) ( after ( implantation ( -LRB- ( 125,126 -RRB- ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Recent) (NNS studies)) (VP (VBG using) (NP (NP (JJ human) (JJ recombinant) (NN BMP-2)) (PP (IN in) (NP (JJ cell-free) (NN collagen) (NNS sponges)))) (S (VP (TO to) (VP (VB heal) (NP (NN articular) (NN cartilage) (NNS defects)) (PP (IN in) (NP (NNS rabbits)))))))) (VP (VBD demonstrated) (NP (NN repair) (NN tissue)) (S (VP (VBG containing) (NP (NP (NN type) (NNP II) (NNP collagen)) (PP (IN at) (NP (CD 24) (NNS weeks)))) (PP (IN after) (NP (NP (NN implantation)) (PRN (-LRB- -LRB-) (NP (CD 125,126)) (-RRB- -RRB-))))))) (. .)))
Recent studies using human recombinant BMP-2 in cell-free collagen sponges to heal articular cartilage defects in rabbits demonstrated repair tissue containing type II collagen at 24 weeks after implantation (125,126).
(ROOT (S (NP (JJ Lamprey) (NN cartilage)) (VP (VBZ contains) (NP (DT no) (NN collagen))) (. .)))