Objective To investigate the adaptive response of patella patellar tendon junction (PPTJ) and tibial patellar tendon junction (TPTJ) in rabbits under short-term jumping loads. Methods Nineteen 18-week old female New Zealand white rabbits were randomly divided into control group (n=4) and 1-day jump (J1), 3-day jump (J3), 5-day jump (J5) group (n=5 in each group). Electrical stimulation quantitative jumping device was used to make rabbits complete 150 jumps per day (10 groups × 15 jumps, 3 minutes’ per group, 6 minutes rest after completion of 4th and 8th groups, 3 minutes rest after completion of the other groups, the average jumping speed was 0.083 times/s, the total training time per day was about 70 minutes). The rabbits were executed at 24th hour after the training. The corresponding knee tissues from left and right hind limbs were taken for HE staining and immunohistochemistry. The histomorphological results were qualitatively described. The cell density, cartilage thickness, and the expression of IL-1β, IL-6, and TGF-β1 were quantitatively monitored. Results The micro-injury of PPTJ and TPTJ occurred at different degrees in jump groups (J1, J3, J5 groups). The IL-1β and IL-6 expressions of PPTJ in J5 group were significantly higher than those in control group and J1 group; the IL-6 expressions of PPTJ in J3 group were significantly higher than those in control group; the thickness of TPTJ cartilage band in J5 group was significantly greater than that in control, J1 and J3 groups; in control group, the IL-1β and IL-6 expressions of PPTJ were significantly lower than those of TPTJ; in J1 group, the IL-1β, TGF-β1, IL-6 expressions of PPTJ were significantly lower than those of TPTJ；in J3 group, the IL-6 expressions of PPTJ were significantly lower than those of TPTJ. ConclusionsThe pathological changes of PPTJ induced by short-term jumping loads were earlier than those of TPTJ. The rabbit PPTJ inflammatory factors IL-1β and IL-6 were up-regulated during injury process under short-term jumping loads, but there was no significant change of inflammatory factors in rabbit TPTJ. The results provide laboratory evidence for the pathogenesis of patellar tendinopathy.