Objective:To evaluate the acute effects of different foot-strike patterns of running on knee cartilage in amateur marathon runners using the T 2* mapping technique. Methods:From November 2021 to February 2022, 29 amateur marathon runners were recruited in Hangzhou. The gait analysis was performed to determine their landing patterns, then the runners were divided into the fore-foot strike (FFS) group (11 cases) and the rear-foot strike (RFS) group (18 cases). The MRI of the knee joint of the dominant leg was performed before and 30 min after running, and the volume, thickness, and T 2* value of each division of knee cartilage were measured. Independent samples t-tests were used to compare the differences in baseline data before running between the groups, and paired samples t-tests were used to compare the differences before and after running within the groups. Results:The difference in knee cartilage volume and thickness between the FFS and RFS groups before running was not statistically significant ( P>0.05), and the T 2* value of the femur medial posterior in the RFS group was higher than that of the FFS group ( t=-2.47, P=0.020). Compared with pre-running, cartilage thickness of the tibia lateral posterior decreased in the FFS group after running ( t=-2.96, P=0.016), and cartilage thickness of the tibia lateral posterior and patella lateral central decreased in the RFS group ( t=-3.25, -3.02, P=0.004, 0.007). Cartilage volume of the tibia lateral posterior decreased in the FFS group after running ( t=-2.58, P=0.030), and the cartilage volume of the patella lateral central decreased in the RFS group ( t=-2.74, P=0.013). The differences in T 2* values of cartilage in each region before and after running were not statistically significant in the FFS group ( P>0.05), whereas in the RFS group, the cartilage T 2* values in the femur medial posterior, femoral trochanter central, femoral trochanter lateral, femur lateral central, tibia lateral anterior, tibia medial posterior, tibia medial central, and tibia medial anterior decreased ( P<0.05). Conclusions:After running, FFS showed changes in morphology and biochemical composition only in some subregions of tibial cartilage, whereas most of the femoral cartilage, patellar cartilage, and tibial cartilage regions were altered by RFS. The RFS pattern introduces greater acute changes in cartilage in the knee joint.

OBJECTIVETo characterize the role of tumor necrosis factor-α (TNF-α) and NF-κB play a role in macrophage-like THP-1 cells promoting coal tar pitch extract (CTPE)-induced tumorigenic transformation of human bronchial epithelial cells (BEAS-2B).

METHODSFrom passage 10, CTPE-induced BEAS-2B cells cocultured with THP-1 cells were treated with NF-κB inhibitor-Pyrrolidine dithiocarbamate (PDTC) every 3 passages and TNF-α antibody every passage. Alterations of cell cycle, karyotype and colony formation in soft agar of BEAS-2B cells at passages 20, indicative of tumorigenicity, were determined, respectively. In addition, mRNA and protein levels of TNF receptor associated factor2 (TRAF2) and Cyclin D1 in BEAS-2B cells were measured with Real Time-PCR and Western blot, respectively.

RESULTSThe percentages of S-phase BEAS-2B cells at passage 20 in PDTC group and TNF-α antibody group were (33.97±2.16)% and (34.29±2.04)% respectively, which were less than that in Co-culture+CTPE group of 20th passage [(44.46±0.83)%], P < 0.05; The number of cells with aneuploidy in 100 cells in 20th passage PDTC group and TNF-α antibody group were 40 and 37, and there were significantly different when comparing to that of 20th passage Co-culture+CTPE group (75); The number of colony formation and the rate of colony formation of BEAS-2B cells in soft agar at passage 20 in PDTC group were (15.17±2.48) and (1.51‰±0.25‰), (13.33±2.58)and (1.33‰±0.26‰) in TNF-α antibody group, which were less that those in 20th passage Co-culture+CTPE group [(172.33±12.09) and (17.23‰±1.20‰)], P < 0.05; at the same time, the mRNA and protein levels of TRAF2 and Cyclin D1 in BEAS-2B cells were decreased after PDTC and TNF-α antibody treatment.

CONCLUSIONTNF-α and NF-κB could play an important role in THP-1 cells promoting coal tar pitch extract-induced tumorigenic transformation of BEAS-2B cells by influencing the expression of TRAF2 and Cyclin D1.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; drug effects ; Coal Tar ; toxicity ; Cyclin D1 ; metabolism ; Epithelial Cells ; cytology ; Humans ; Macrophages ; cytology ; NF-kappa B ; metabolism ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism