title: Mechanical effects of the intraarticular administration of high molecular weight hyaluronic acid plus phospholipid on synovial joint lubrication and prevention of articular cartilage degeneration in experimental osteoarthritis.
abstract: OBJECTIVE
  To examine in vivo the effects of a mixture of high molecular weight hyaluronic acid (HA) plus phospholipids on joint lubrication and articular cartilage degeneration.
  
  
  METHODS
  Experimental osteoarthritis (OA) of the right knee was induced by anterior cruciate and medial collateral ligament transection in 40 rabbits. The animals were subjected to 8 consecutive weekly intraarticular administrations of high molecular weight HA (the HA200 group), conventional molecular weight HA (the HA80 group), or high molecular weight HA plus L-delta dipalmitoyl phosphatidylcholine liposomes (the PHA group) and were killed 1 week after the final injection. The remaining transected right knees (the OA group) and randomly selected nontransected contralateral left knees (the control group) were collected simultaneously. Each group (n = 10) was divided into 2 equal subgroups, one of which was evaluated histologically while the other was subjected to a lubricating ability test using a pendulum friction tester.
  
  
  RESULTS
  The injected knees had a tendency to demonstrate less damage to the articular cartilage compared with the OA group, and the histologic findings in all groups except for the PHA group differed significantly from the control group. There was a significant difference in the mean +/- SD friction coefficient between the control group (0.0100 +/- 0.00300) and the OA (0.0206 +/- 0.00649), HA200 (0.0190 +/- 0.00427), and HA80 (0.0177 +/- 0.00712) groups (P < 0.05 for each comparison), but not between the control group and the PHA group (0.0150 +/- 0.00330) (P = 0.15).
  
  
  CONCLUSIONS
  To our knowledge, this is the first in vivo study to examine whether intraarticular injections of phospholipids influence joint lubrication by acting as a boundary lubricant, thus protecting articular cartilage from degenerative changes.
authors.affiliation: Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kawano
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Miura
authors.forename: Taro
authors.initials: T
authors.lastname: Mawatari
authors.forename: Takaaki
authors.initials: T
authors.lastname: Moro-Oka
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Higaki
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology*; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000737:chemistry / Q000494:pharmacology*; D007270:Injections, Intra-Articular; D008153:Lubrication; D008297:Male; D017888:Medial Collateral Ligament, Knee / Q000601:surgery; D008970:Molecular Weight; D020370:Osteoarthritis, Knee / Q000188:drug therapy / Q000503:physiopathology* / Q000517:prevention & control*; D010743:Phospholipids / Q000494:pharmacology*; D011817:Rabbits; D013582:Synovial Fluid / Q000187:drug effects; D013583:Synovial Membrane / Q000187:drug effects* / Q000473:pathology
chemical_list: D010743:Phospholipids; D006820:Hyaluronic Acid