[Effect of acupotomy on lipid peroxidation of chondrocytes in rabbits with knee osteoarthritis].

Objectives: To observe the effect of acupotomy on expression of long-chain acyl-CoA synthetase 4 (ACSL4), lysophosphatidylcholine acyltransferase 3 (LPCAT3), malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) in knee cartilage of rabbits with knee osteoarthritis (KOA), so as to explore whether acupotomy can treat KOA by inhibiting lipid peroxidation of chondrocytes.

Methods: Six-month-old New Zealand male rabbits were randomly divided into control, model, acupotomy and electroacupuncture (EA) groups, with 7 rabbits in each group. The KOA model was established by left hindlimb straightening fixation according to Videman method. In the acupotomy group, the high stress points, such as tendons attachment points of the vastus medialis, vastus lateralis, rectus femoris, biceps femoris and pes anserine bursa of the left hind limb knee joint were selected for acupotomy lysis treatment, once a week for 3 weeks. In the EA group, EA (2 Hz/100 Hz, 3 mA) was applied to "Neixiyan" (EX-LE4), "Dubi" (ST35), "Xuehai" (SP10) and "Liangqiu" (ST34) of the left hind limb of rabbits for 20 min, once every other day for 3 weeks. Before and after the treatment, Lequesne MG score and passive range of motion (PROM) of knee joint were detected in each group. After the treatment, safranin O-fast green staining was used to observe the morphological changes of rabbit knee cartilage and Mankin scoring was evaluated. Immunohistochemistry method was used to detect the location and positive expression of ACSL4. Western blot was used to detect the protein expression levels of ACSL4 and LPCAT3, and TBA and ELISA methods were used to detect the expression levels of MDA and 4-HNE in the affected knee cartilage, respectively.

Results: Compared to the control group, the Lequesne MG score was significantly increased (P<0.01), while PROM was significantly decreased (P<0.01) in the model group;after the intervention and compared to the control group, the model group exhibited significant increase in Mankin score, enhancement in the positive expression of ACSL4 in knee cartilage (P<0.01), along with significant elevation in ACSL4 and LPCAT3 protein expression levels (P<0.01), as well as elevated contents of MDA and 4-HNE (P<0.01). Compared to the model group, both the acupotomy group and EA group showed significant reductions in Lequesne MG score (P<0.01) and increases in PROM (P<0.01). Additionally, there were marked decreases in Mankin score and the positive expression of ACSL4 in knee cartilage (P<0.01), as well as significant decreases in the protein expression levels of ACSL4 and LPCAT3 (P<0.01). Moreover, the contents of MDA and 4-HNE decreased significantly (P<0.01, P<0.05). Compared to the EA group, the acupotomy group exhibited reduced Lequesne MG score (P<0.01), increased PROM (P<0.01), significant reductions in ACSL4 and LPCAT3 protein expression levels (P<0.01), and lowered content of MDA (P<0.01). Post-intervention, both groups showed significant reductions in Lequesne MG score (P<0.01) and significant increases in PROM (P<0.01) compared to their respective pre-intervention data.

Conclusions: Acupotomy intervention can down-regulate the levels of ACSL4, LPCAT3, MDA and 4-HNE in knee cartilage, improve the behavior of affected limbs, indicating that acupotomy therapy may inhibit lipid peroxidation in chondrocytes and slow down cartilage injury to treat KOA.