Zisheng Shenqi decoction ameliorates monosodium urate crystal-induced gouty arthritis in rats through anti-inflammatory and anti-oxidative effects

Abstract

Based on traditional Chinese medicinal theories on gouty arthritis, Zisheng Shenqi decoction (ZSD), a novel Chinese medicinal formula, was developed due to its multiple functions, including reinforcing renal function, promoting blood circulation and relieving pain. In the present study, the effect of ZSD on monosodium urate (MSU) crystal-induced gouty arthritis in rats was investigated and the underlying mechanisms were examined. The data from these investigations showed that the injection of MSU crystals into the ankle joint cavity caused significant elevations in ankle swelling and inflammatory cell infiltration into the synovium, whereas these abnormal changes were markedly suppressed by oral administration of ZSD (40 mg/kg) for 7 days. Mechanically, ZSD treatment prevented MSU crystal‑induced inflammatory responses, as evidenced by downregulation in the expression levels of NACHT domain, leucine‑rich repeat and pyrin domain containing protein (NALP) 1 and NALP6 inflammasomes, decreased serum levels of tumor necrosis factor‑α and interleukin‑1β, and inhibited activation of nuclear factor‑κB. In addition, ZSD administration markedly enhanced the anti-oxidant status in MSU crystal‑induced rats by the increase in the activities of superoxide dismutase and glutathione peroxidase, and the levels of reduced glutathione. These results indicated that ZSD effectively prevented MSU crystal-induced gouty arthritis via modulating multiple anti‑oxidative and anti‑inflammatory pathways, suggesting a promising herbal formula for the prevention and treatment of gouty arthritis.

Figure 1

Effect of ZSD on ankle oedema in rats with MSU crystal-induced gouty arthritis. The treatment groups were as follows: Control=normal control rats; Model=MSU crystal-induced rats; Col=MSU crystal-induced rats pretreated with colchicine (0.28 mg/kg); L-ZSD=MSU crystal-induced rats pretreated with ZSD (10 mg/kg); M-ZSD=MSU crystal-induced rats pretreated with ZSD (20 mg/kg); H-ZSD=MSU crystal-induced rats pretreated with ZSD (40 mg/kg). (A) Measurement of the left ankle circumference of each rat was recorded following MSU injection for 24 h. (B) Representative images of the left leg from each group are shown. Arrows indicate the position of the measurement. Data are presented as the mean ± standard deviation (n=6). ^**P<0.01, vs. control group; ^##P<0.01, vs. model group. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; Col, colchicine.

Figure 2

Effect of ZSD on MSU crystal-induced synovial damage and inflammatory cell infiltration in rats with gouty arthritis rats. Representative images of sections of the synovium from control rats, model rats, Col-treated rats and ZSD (10, 20 and 40 mg/kg, respectively)-treated rats stained with hematoxylin and eosin for histological assessment. Original magnification. ×200. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; Col, colchicine.

Figure 3

Effect of ZSD on serum levels of TNF-α and IL-1β in rats with MSU crystal-induced gouty arthritis. The serum levels of TNF-α and IL-1β in each rat from control group, model group, Col treatment group and ZSD treatment groups were determined using enzyme-linked immunosorbent assay. Data are presented as the mean ± standard deviation (n=6). ^**P<0.01. vs. control group; ^#P<0.05 and ^##P<0.01, vs. model group. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; TNF-α, tumor necrosis factor-α; IL-1β, interleukin-1β; Col, colchicine.

Figure 4

Effect of ZSD on MSU crystal-induced NF-κB activation in the synovium of rats. The expression levels of cytoplasmic IκB and nuclear NF-κB p65 in synovial tissues from each treatment group were measured using western blot analysis. Representative bands are shown (left), and the relative band intensity ratio was analyzed (right). Data are presented as the mean ± standard deviation (n=6). ^**P<0.01, vs. control group; ^##P<0.01, vs. model group. C, cytoplasm; N, nuclear. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; Col, colchicine; NF-κB, nuclear factor-κB; IκB, inhibitor of NF-κB.

Figure 5

Effect of ZSD on the protein expression levels of NALP1 and NALP6 in the synovium of rats with MSU crystal-induced gouty arthritis. The expression levels of NALP1 and NALP6 in synovial tissues from each group were determined using western blot analysis. Representative bands are shown (left), and the relative band intensity ratio was analyzed (right). Data are presented as the mean ± standard deviation (n=6). ^**P<0.01, vs. control group; ^##P<0.01, vs. model group. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; Col, colchicine; NALP, NACHT domain, leucine-rich repeat and pyrin domain containing protein.

Figure 6

Effect of ZSD on the anti-oxidant status of serum obtained from rats with MSU crystal-induced gouty arthritis. The activities of SOD and GSH-Px, and the levels of GSH in the serum of each rat from the control group, model group, Col treatment group and ZSD treatment groups were measured. The data are presented as the mean ± standard deviation (n=6). ^**P<0.01, vs. control group; ^#P<0.05 and ^##P<0.01; vs. model group. ZSD, Zisheng Shenqi decoction; MSU, monosodium urate; Col, colchicine; SOD; superoxide dismutase; GSH-Px, glutathione peroxidase; GSH, reduced glutathione.