To observe the protective effect of Bushen Zhuangjin Decoction on cartilage damage in knee osteoarthritis (KOA) rats with kidney deficiency and blood stasis type, and to explore its molecular mechanism.

Seventy female SD rats were divided into 7 groups by a random digital table, with 10 in each. Except the normal group, the others were established kidney deficiency and blood stasis type KOA models. Each 1 rat was selected from the model group and the normal group, which were euthanized to verify successful modeling. Among the others, the positive drug group was given a dose of 5.4 mg/kg of etoposide by gavage. The low, medium, and high dose groups of Bushen Zhuangjin Decoction were given Bushen Zhuangjin Decoction 2.1, 4.2, and 8.4 g/kg by gavage respectively. SB203580 group was orally administered with SB203580 3.0 mg/kg. The model group was given 1 mL/100 g of physiological saline by gavage. The other 10 female SD rats were given an equal volume of physiological saline by gavage (normal group). All lasted for 30 days. Enzyme linked immunosorbent assay was used for detecting tumor necrosis factor-α (TNF)-α, interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels in joint fluid. Hematoxylin eosin (HE) staining was used to observe the pathological changes of cartilage tissues, and the Mankin scores were compared. Real time reverse transcription polymerase chain reaction (RT-qPCR) was used to detect p38 mitogen activated protein kinase (p38MAPK) and nuclear transcription factors in various groups of cartilage tissues-κB p65 (NF-κB p65), nucleotide binding oligomerization domain like receptor 3 (NLRP3), and aspartate proteolytic enzyme 3 (Caspase3) gene expressions. Western blotting (WB) was used for detecting p38MAPK and NF-κB p65, NLRP3, Caspase3 protein expressions and p-p38MAPK levels in cartilage tissues.

KOA models of kidney deficiency and blood stasis type were successfully established. The TNF-α, IL-1β, IL-6 levels of joint fluid, Mankin score, p38MAPK gene, NF-κB p65, NLRP3, Caspase3 expressions and p-p38MAPK in knee cartilage tissues in the model group were all higher than those in the normal group (P <0.01), of which the treatment groups were all lower than the model group (P <0.01), and except for Caspase3 expressions the indexes in the high-dose group of Bushen Zhuangjin Decoction were lower than the SB203580 group (P <0.01), and the effect of Bushen Zhuangjin Decoction was dose-dependent. The cartilage tissue of the model group rats showed severe pathological changes, and the treatment groups all showed relief, and the effects of the low-dose and positive drug groups of Bushen Zhuangjin Decoction, the medium dose group of Bushen Zhuangjin Dectoction and SB203580 group were basically equivalent.

Bushen Zhuangjin Decoction can alleviate the inflammatory response of cartilage tissue in KOA rats with kidney deficiency and blood stasis type, and it is speculated to inhibit p38MAPK/NF-κB pathway achieves this effect.