Research Of Therapeutic Effect Of L-theanine On Osteoarthritis

Osteoarthritis(OA),which is a common joint disease in older animals that severely affects normal function of joints in animals,reduces the quality of life.The treatments in clinical include Joint replacement surgery,non-steroidal anti-inflammatory drugs(NSAIDs),and improvement of feeding and management.However,each method has certain limitations.Therefore,it is urgent to find drugs with small side effects and long-term use.The extracts from plant has gradually become a hotspot in recent years.L-Theanine is a non-protein amino acid in green tea which has a lot of biological activities,including anti-inflammatory,anti-tumor and anti-apoptosis.Based on this,we compared L-Theanine with non-steroidal anti-inflammatory drugs(celecoxib)by anterior cruciate ligament amputation(ACLT)to explore the protective effect of L-Theanine on rat model of OA.At the same time,we apply the drug to dogs suffering in OA in clinical trials to observing the effect.Experiment design: The experiment was divided into the sham group,the model group,L-Theanine treatment group(divided into low,medium and high doses)and celecoxib group using the ACLT model.The blank group and model group received 1 mL saline on the second day after surgery.The treatment group administrated L-Theanine(50 mg/kg,100 mg/kg,200 mg/kg)with gavage consecutively for six weeks;The group which received celecoxib(2.86 mg/kg)in the fourth week,lasted to the sixth week.All animals were sacrificed euthanasia 6 weeks later.Serum and articular cartilage were collected to detect the levels of iNOS,NO,COX-2 and PGE2 and the tibias dealing with formalin fixation were used for HE staining and safranin O-solid green staining.we used the 2nd generation chondrocytes to the ex vivo experiments divided into 5 groups;1)the control group;2)IL-1? group: 10 ng/mL IL-1? stimulated the chondrocytes for 24 h;3)experimental group: 10 ng/mL IL-1? pretreatment for 24 h,and then 50 ?M,100 ?M,and200?M L-Theanine were added co-operated for 24 h.Gene expression and protein levels of matrix metalloproteinase(MMP)-13 and(MMP)-3 and cyclooxygenase-2(COX-2)and iNOS were determined in vitro by quantitative real-time-polymerase chain reaction and Western blotting.ProstaglandinE2(PGE-2)and NO amounts in the culture medium were determined by enzyme-linked immunosorbent assay(ELISA).Excepted that,we observed wheather L-Theanine could alleviate the symptoms of the dogs suffered OA.Results: L-Theanine lower the amounts of cytokine,including iNOS?NO?COX-2 and PGE-2which was generated by ACLT.The histological injury of cartilage was alleviated similarly with L-Theanine(200 mg/kg)and celecoxib(p.o.).L-Theanine inhibited Interleukin(IL)-1?-inducedchondrocyte gene and protein expressions of MMP-3,MMP-13,COX-2 and iNOS in a dose-dependent manner and reduced PGE-2 and NO amounts in the culture medium in vitro.The clinical acessment showed that L-Theanine can relieve the joint sensitivity,gait tension and posture abnormality of OA dogs and improve its quality of life.Conclusion: L-Theanine can inhibit inflammatory responses in rat chondrocytes in vitro and reduce articular cartilage damage in vivo,confirming the potential therapeutic value of L-Theanine in OA.