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Journal of Experimental Orthopaedics
Fig. 4 | Journal of Experimental Orthopaedics

Fig. 4

From: Intra-articular interleukin-1 receptor antagonist (IL1-ra) microspheres for posttraumatic osteoarthritis: in vitro biological activity and in vivo disease modifying effect

Fig. 4

The disease-modifying activity of IL-1 ra or PLGA IL-1 ra in the rat ACLT model. a Cartilage histopathology scores of control joints and joints undergoing ACLT and receiving weekly intra-articular injections of PBS (n = 9), IL-1 ra (n = 13), PLGA-encapsulated IL-1 ra (PLGA IL-1 ra; n = 14) or PLGA microspheres (PLGA; n = 6) for 4 weeks starting one week following ACLT. PBS treated ACLT joints exhibited a significantly higher mean cartilage histopathology score compared to control. Similarly, PLGA-treated ACLT joints exhibited a significantly higher mean cartilage histopathology score compared to control. PLGA IL-1 ra treated ACLT joints demonstrated a significantly lower mean cartilage histopathology score compared to PBS or PLGA-treated ACLT joints. *p < 0.001. Data represents average ± SD. b Representative Safranin O/Fast Green stained tibial plateau cartilage specimens from control, ACLT animals receiving PBS, IL-1 ra, PLGA-IL1 ra or PLGA. ACLT joints exhibited loss of Safranin O staining indicative of glycosaminoglycan loss, clefts extending into the middle zone and hypocellularity. PLGA IL-1ra treatment reduced glycosaminoglycan loss and the number and depth of cartilage tissue fissures. Scale = 100 μm. c Synovial histopathology scores of control joints and joints undergoing ACLT and receiving weekly intra-articular injections of PBS (n = 9), IL-1 ra (n = 13), PLGA IL-1 ra (n = 14) or PLGA (n = 6) for 4 weeks starting one week following ACLT. PBS treated ACLT joints exhibited a significantly higher mean synovial histopathology score compared to control. Similarly, PLGA-treated ACLT joints exhibited a significantly higher mean synovial histopathology score compared to control. IL-1 ra treated ACLT joints exhibited a significantly lower mean synovial histopathology score compared to PBS or PLGA-treated ACLT joints. Similarly, PLGA Il-1 ra treated ACLT joints exhibited a significantly lower mean synovial histopathology score compared to PBS or PLGA-treated ACLT joints. *p < 0.001. Data represents average ± SD. d Representative H&E-stained synovia specimens from control, ACLT animals receiving PBS, IL-1 ra, PLGA IL-1 ra or PLGA. Arrows point to synovial hyperplasia evident in ACLT animals treated with PBS, IL-1 ra and PLGA

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