Degradation of Proteoglycans and Collagen in Equine Meniscal Tissues.

Investigate meniscal extracellular matrix degradation. Equine menisci (n = 34 from 17 horses) were studied. Site-matched sections were cut and scored from three regions (ROIs; n = 102) and stained for histology, proteoglycan (safranin O and fast green), aggrecan, and collagen cleavage (NITEGE, DIPEN, and C1,2C antibodies, respectively). Picrosirius red and second harmonic generation microscopy were performed to investigate collagen ultrastructure. A total of 42 ROIs met the inclusion criteria and were included in the final analysis. The median (range) ROI histological score was 3 (0-9), providing a large spectrum of pathology. The median (range) proteoglycan score was 1 (0-3), representing superficial and central meniscal loss. The median (range) of DIPEN, NITEGE, and C1,2C scores was 1 (0-3), revealing immunostaining of the femoral and tibial surfaces. The proteoglycan scores exhibited significant positive associations with both histologic evaluation (p = 0.03) and DIPEN scores (p = 0.02). Additionally, a robust positive association (p = 0.007) was observed between the two aggrecanolysis indicators, NITEGE and DIPEN scores. A negative association (p = 0.008) was identified between NITEGE and histological scores. The C1,2C scores were not associated with any other scores. Picrosirius red and second harmonic generation microscopy (SHGM) illustrated the loss of the collagen matrix and structure centrally. Proteoglycan and collagen degradation commonly occur superficially in menisci and less frequently centrally. The identification of central meniscal proteoglycan and collagen degradation provides novel insight into central meniscal degeneration. However, further research is needed to elucidate the etiology and sequence of degradative events.

Effects of a training intervention tailored to the menstrual cycle on endurance performance and hemodynamics.

BACKGROUND: This study aimed to compare the effects of block periodized training and training adapted to the menstrual cycle (MC) phases on endurance performance, cardiovascular parameters, recovery, and MC-related symptoms in active females. METHODS: Fourteen naturally menstruating, moderately trained females (age: 24±3 years; BMI: 22.3±2.7) were randomized into an intervention (INT) and a control (CON) group. Throughout an 8-week intervention period, both groups participated in a polarized training program. In the INT, the training sessions were adapted to the MC with higher training loads within the mid and late follicular phase. Before and after the intervention maximal oxygen consumption (VO2max), velocity and heart rate at ventilatory thresholds one and two (vVT1, vVT2, hrVT1, hrVT2), systolic and diastolic blood pressure (sBP, dBP), root mean square of successive RR interval differences (RMSSD), standard deviation of NN intervals (SDNN), pulse wave velocity (PWV), and the premenstrual assessment form (PAF) were assessed. RESULTS: There were no significant time × group interaction effects in all physiological parameters (VO2max: P=0.890; vVT1: P=1.000; hrVT1: P=0.464; vVT2: P=0.356; hrVT2: P=0.762 sBP: P=0.948; dBP: P=0.203; RMSSD: P=0.257; SDNN: P=0.241; PWV: P=0.818), or psychological parameters (PAF: P=0.745). CONCLUSIONS: Tailoring a polarized training program to the MC did not augment training responses compared to a regular training program in active females. However, a substantial portion of the training intervention in the CON was coincidentally matched to the MC.