Effects of knee injection on skeletal muscle metabolism and contractile force in rats.

OBJECTIVE: We tested the hypothesis that intrusion of the knee joint capsule alters quadriceps muscle metabolism and function independently from the damage induced to knee cartilage. METHODS: Adult rats were separated into four groups: intraarticular injections of saline (SAL; n=9); intraarticular injections of papain, a model for osteoarthritis (PIA; n=7); sham injections (SHAM; n=8); and controls (CTL; n=5). 31P magnetic resonance spectroscopy (31P-MRS) was performed after 2 weeks. Spectra were obtained from the left quadriceps: two at baseline, eight during electrical stimulation with simultaneous measurement of contractile force, and 15 during recovery. 31P-MRS data were presented as the ratio of inorganic phosphate (Pi) to phosphocreatine (PCr), concentrations of PCr [PCr], intramuscular pH, and the rates and time constants of PCr breakdown during stimulation and PCr recovery. Intramuscular cytokine concentrations were measured within the quadriceps. Histologic slides of the knees were scored for severity of cartilage damage. RESULTS: The interventional groups produced values of Pi/PCr ratio, [PCr], contractile force and pH that were significantly different from CTL. These changes in muscle function were accompanied by higher concentrations of interleukin-1 observed with PIA and SAL. We did not observe any effect of cartilage damage on muscle function or metabolism. CONCLUSIONS: Knee joint intrusion alters quadriceps muscle metabolism with accelerated depletion of energy stores and fatigue during stimulation. This study demonstrates that needle intrusion into the knee joint results in muscle dysfunction, independently from the extent of cartilage damage.

Osteoarthritis: no cure, but many options for symptom relief.

Because curative disease-modifying medications for osteoarthritis are still not available, medical management strategies focus on pain relief. Other goals are to identify functional deficits early and to start restorative, if not preventive, rehabilitation. We review recent developments and summarize the clinical features and treatments currently available.

[Effect of an essence-restoring decoction on DNA repair capacity].

In order to observe the effect on organism DNA repair capacity after administration of Essence-Restoring Decoction (ERD), the level of peripheral lymphocyte unscheduled DNA synthesis (UDS) in 20 healthy young men, 23 healthy old men and 13 old men given ERD were detected, while the frequency of sister chromosome exchange (SCE) of mice marrow cells in 80 ICR strain male mice were detected. Ultraviolet (UV) and mitomycin-C (MMC) were used as agents to induce injury of DNA. Experimental results showed that the level of UDS in the aged person was lower than that of the young person. Comparing the level of UDS of the aged before and after medication, it was shown that the level of UDS after medication was increased, approaching that of the young. Within a range of lower doses (less than 5mg/kg weight), the SCE value of mice marrow cells raised with the increase of MMC concentration, while this values was markedly lowered in the medicated mice as compared with that of the control. It is thus suggested that ERD could enhance the DNA repair capacity and this might be a part of the mechanism of "Invigorating Kidney and retarding aging" as indicated in TCM.