Table 2.

Cartilage Macroscopic Lesions on Femoral Condyles and Tibial Plateaus in Rabbits

Group	No. of animals	Medial Femoral Condyles		Medial Tibial Plateaus
		Size (mm2)	Grade (0–4 scale)	Size (mm2)	Grade (0–4 scale)
1, OA* 4 weeks	8	7.88 ± 1.51	1.12 ± 0.13	16.88 ± 1.83	1.12 ± 0.13
2, OA† 8 weeks	8	17.88 ± 3.48	1.62 ± 0.26	19.88 ± 2.61	1.75 ± 0.25
3, IL-1Ra 500 μg‡ 8 weeks	4	11.50 ± 2.90	2.00 ± 0.41	17.50 ± 4.06	1.50 ± 0.29
4, IL-1Ra 1000 μg§ 8 weeks	8	9.25 ± 1.75 (P < 0.04)¶	1.44 ± 0.18	14.62 ± 2.19	1.31 ± 0.16

*Rabbits were killed and tissue examined at 4 weeks post-medial meniscectomy. No treatment was given to these rabbits.

^†Rabbits received intra-articular injections for 3 consecutive days beginning 4 weeks after surgery. The preparation contained 1000 μg of the vector VR1012 complexed to the lipid gAP-DLRIE-DOPE in 700 μl of 0.9% sterile saline as vehicle. Rabbits were killed and tissue examined at 8 weeks post medial meniscectomy.

^‡Rabbits received intra-articular injections for 3 consecutive days beginning 4 weeks post medial meniscectomy. The preparation contained 500 μg of plasmid DNA (Vector VR1012) containing the coding sequence of the canine IL-1Ra gene complexed to the lipid gAP-DLRIE-DOPE (500 μg) in 700 μl of sterile 0.9% saline. Rabbits were killed and tissue examined 8 weeks after surgery.

^§Rabbits received intra-articular injections for 3 consecutive days beginning at 4 weeks post medial meniscectomy. The preparation contained 1000 μg of plasmid DNA (Vector VR1012) containing the coding sequence of the canine IL-1Ra gene complexed to the lipid gAP-DLRIE-DOPE (1000 μg) in 700 μl of sterile 0.9% saline as vehicle. Rabbits were killed and tissue examined 8 weeks after surgery.

^¶Statistics were analyzed using the Mann-Whitney U-test; comparison was made with the 8-week OA group. P values < 0.05 were considered significant.