METHODS: Ovariectomized adult female WKY rats were treated with different doses of estrogen (0.2, 2, 20 μg/kg), progesterone (4mg) and testosterone (125 & 250μg/kg) for three consecutive days. At the end of the treatment, the animals were sacrificed and the patellar tendon and lateral collateral ligament were harvested for mRNA and protein expression analyses by Real Time PCR and Western blotting respectively.
RESULTS: RXFP1, the main isoform expressed in these knee structures and RXFP2 showed a dose-dependent increase in expression with estrogen. Progesterone treatment resulted in an increase while testosterone caused a dose-dependent decrease in the mRNA and protein expression of both relaxin receptor isoforms.
DISCUSSION: Progesterone and high dose estrogen up-regulate while testosterone down-regulates RXFP1 and RXFP2 expression in the patellar tendon and lateral collateral ligament of rat's knee.
CONCLUSION: Relaxin receptor isoforms up-regulation by progesterone and high dose estrogen could provide the basis for the reported increase in knee laxity while down-regulation of these receptor isoforms by testosterone could explain low incidence of non-contact knee injury in male.
Methods: Fifty-seven participants were assessed for their demographics and functional ability relating to the requirement for walking devices, including the Timed Up and Go Test (TUGT) and lower limb loading during sit-to-stand (LLL-STS).
Results: Thirty-five participants (61%) used a walking device, particularly a standard walker, for daily walking. More than half of them (n = 23, 66%) had potential of walking progression (i.e., safely walk with a less-support device than the usual one). The ability of walking progression was significantly associated with a mild severity of injury, increased lower-limb muscle strength, decreased time to complete the TUGT, and, in particular, increased LLL-STS.
Conclusion: A large proportion of ambulatory individuals with SCI have the potential for walking progression, which may increase their level of independence and minimise the appearance of disability. Strategies to promote LLL-STS are important for this progression.