Table II.

Lubricin quantification in naturally occurring injuries and experimental animal models of osteoarthritis. ELISA – enzyme-linked immunosorbent assay, IF – immunofluorescence, WB – Western blot, PCR – polymerase chain reaction, MS – mass spectrometry, SF – synovial fluid, SM – synovial membrane, OA – osteoarthritis, OCD – osteochondrosis dissecans, wk – week, ACLT – anterior cruciate ligament transection, DMM – destabilization of the medial meniscus, MFC – medial femoral condyle, MCLT – medial collateral ligament transection, PCLT – posterior cruciate ligament transection, * – AlphaLISA.

	Species	Model	Assay					Control	Outcome (Lubricin)
			ELISA	IF/IHC	WB	PCR	MS
48	Horse	Cartilage defect			✓			Time 0 baseline sample	SF [lubricin] increased post-injury
46	Horse	Carpal osteochondral fragment model; naturally occurring carpal OA	✓	✓		✓		Contralateral sham-operated joint	SF [lubricin] increased post-injury; SM lubricin staining increased post-injury; PRG4 expression increased in SM but decreased in cartilage post-injury
49	Horse	Late stage OA; acute joint injury; OCD	*		✓			Healthy equine joints	SF [lubricin] increased post-injury (*AlphaLISA)
50	Horse	Carpal osteochondral fragment model	✓					Contralateral sham-operated joint	SF [lubricin] increased post-injury
47	Horse	Carpal osteochondral fragment model, talar impact model, stifle cartilage defect model	✓					Time 0 baseline sample	SF [lubricin] increased post-injury
51	Horse	Naturally occurring carpal and fetlock injury; acute <3 wk, chronic > 3 wk			✓			Contralateral uninjured joints	SF [lubricin] increased post-injury, with acute injury higher than chronic injury
45	Dog	ACLT	✓					Healthy canine synovial fluid	SF [lubricin] increased post-injury
44	Dog	ACLT		✓				Contralateral non-operated joint	Lubricin staining depth increased post-injury
63	Mouse	DMM		✓	✓			Non-operated mice; contralateral sham-operated joint	Lubricin staining & Prg4 expression increased post-injury
64	Sheep	MFC full thickness defect; fetal and adult					✓	Twin lamb joint, healthy adult sheep joint	Fetal: PRG4 expression increased post-injury Adult: PRG4 expression not changed post-injury
65	Sheep	ACLT/MCLT or lateral meniscectomy	✓					Contralateral unoperated joint, sham-operated joint	SF [lubricin] not changed
67	Sheep	Lateral meniscectomy		✓		✓		Sham-operated sheep joints	Lubricin staining and PRG4 expression decreased post-injury
25	Rat	ACLT	✓	✓				Sham-operated rat joint	SF [lubricin] and staining decreased post-injury
26	Rat	ACLT		✓		✓		Contralateral non-operated joint	I Lubricin staining and Prg4 expression decreased post-injury
66	Rat	Naturally occurring age-related OA	✓	✓	✓			Young, healthy rat joint	SF [lubricin], staining and protein expression decreased with age-related OA
34	Rat	ACLT	✓	✓	✓			Non-operated rat joints	SF [lubricin], staining, and protein expression decreased postinjury
27	Rat	ACLT	✓	✓		✓		Non-operated rat joints	SF [lubricin], lubricin staining, and Prg4 expression decreased post-injury
32	Rat	ACLT		✓		✓		Non-operated rat joints	Lubricin staining and expression decreased post-injury
33	Rat	ACLT		✓				Non-operated rat joints	Lubricin staining decreased post-injury
31	Rat	ACLT		✓				Non-operated rat joints	Lubricin staining decreased post-injury
35	Rat, mouse	ACLT		✓				Sham-operated mice and rat joints	Lubricin staining and expression decreased in ACLT + vehicle-treated joints post-injury
36	Mouse	ACLT		✓				Sham-operated or vehicle-injected mouse joints	Lubricin staining decreased post-injury
30	Guinea pig	ACLT	✓		✓			Non-operated guinea pig joints, contralateral nonoperated joint	SF [lubricin] and expression decreased post-injury
29	Guinea pig	ACLT; naturally occurring age-related OA	✓					Non-operated guinea pig joints	SF [lubricin] decreased post-injury
8	Rabbit	ACLT & PCLT	✓		✓			Non-operated rabbit joints, sham-operated joint	SF [lubricin] decreased at weeks 2 & 3 post-injury compared to baseline & week 1 post-injury
28	Rabbit	ACLT			✓	✓		Non-operated rabbit joints, contralateral non-operated joint	SF [lubricin] and Prg4 expression decreased post-injury