22 mL injection of enrofloxacin (China Chemical and Pharmaceutical, Hsinchu, Taiwan) was administered subdermally close to the thigh to prevent suppuration. A partial meniscectomy was performed right away prior to the administration in the test drugs. The animals were housed individually in 350 ?527 ?350 mm (W ?D ?H) steel cages at 22 ?3 and 55 ?20 humidity. Animals had been fed RC4 pellet-type laboratory-animal food with no extra calcium supplement via a stainless steel pellet feeder, and tap water was provided continually.Experimental designbelow the knee joint. The specimens had been fixed in ten buffered formalin for 24 h. Fixed specimens have been cleared of soft tissues and ligaments to allow the gross examination from the articular surfaces with the femoral condyles and the tibial plateau for the scoring on the characteristics of OA pathology.Macroscopic and microscopic specimen examinationsFollowing the partial meniscectomy on the left knee joint, the rabbits were divided into the NT (n = eight), HA (n = eight), DOX (n = 7), and HA-DOX GEL (n = 8) study groups, and received 0.2 mL intra-articular injections of regular saline, DOX (87.191347-94-1 supplier five g/mL), HA (ten mg/mL), or the HA-DOX hydrogel (10 mg/mL HA and 87.1048962-49-7 Data Sheet 5 g/mL DOX), respectively, for the meniscetomized left cavity of your knee joint working with a 1 mL syringe having a 26G hypodermic needle straight away following surgery. The injections had been repeated on three, 6, 9, and 12 d following the meniscectomy.Pain assessmentTriplicate measurements from the hind-paw weight distributions were recorded applying two scales that independently measured the weight borne by each hind paw. The imply percentage ( ) weight distribution of your lefthind paw was calculated 1 d ahead of surgery and on 1, 4, 7, and 13 d after surgery in line with the following equation [36]: weight distribution of left hind paw left weight ??one hundred ight weight ?left weight?The macroscopic examination of your specimens was performed working with a surgical magnifying glass to evaluate the OA progression according to a modification of your parameters described by Colombo et al.PMID:24455443 (1983b). The loss of the superficial layer, the cartilage erosion, the loss on the cartilage luster, the presence of osteophytes, and also the presence of fissures had been evaluated based on the location, variety, and size in the pathological function. Digital photographs of the articular surfaces have been recorded. Histological sections were taken at both femoral condyles, the femoral trochlea, the internal tibial plateau, and also the lateral tibial plateau. The specimens have been separately stained with hematoxylin and eosin (H E), periodic acid Schiff stain, and Alcian blue stain. In the microscopic examination, 9 histological parameters had been scored depending on a previously described grading technique [37] as follows: loss in the superficial layer, the presence of ulceration or erosion (surface fragmentation), the presence of fibrillation, the presence of fissures (V-shaped clefts), the presence of osteophytes and/or chondrophytes, the loss of stainable proteoglycan, the disorganization of chondrocytes, the presence of clones, and also the loss of chondrocytes. Each and every histological parameter was scored on a scale of 0 to 4 in accordance with the severity from the OA, by which cartilage with an appearance that was identical to healthy cartilage in the exact same age was graded as 0, and OA lesions of your worst possible severity were scored as 4. Cartilage thickness was microscopically measured at 10X magnification in increments of 0.01 mm of actual thickness, whe.