Figure 1.

The intervention time point in vivo; osteoarthritis (OA) was induced in 10- to 11-week-old male Sprague Dawley (SD) rats by anterior cruciate ligament transection (ACLT) of the right knee. Sham surgery was performed on the right knee by incision of joint capsule, and sham operation was performed from a separated group of rats. L-theanine (50, 100 or 200 mg/kg, once a day gavage, until the rats were sacrificed), was administrated one day after ACLT surgery. Phosphate-buffered saline (PBS, 1 mL) was used for treatment after sham surgery as a control. Celecoxib (2.86 mg/kg) was used for treatment 4 weeks after ACLT surgery as a positive control.