"Micromotors" could more effectively treat rheumatoid arthritis
Although the drinking of hydrogen-gas-infused water can help treat rheumatoid arthritis, the effects are limited. Scientists have developed what could be a better alternative, though, in the form of tiny injectable gas-emitting "micromotors."
Rheumatoid arthritis has previously been linked to excessive production of reactive oxygen species (ROS) in affected joints. Not only do these chemical molecules oxidize and degrade cartilage and bone, but they also activate the expression of inflammatory proteins known as cytokines.
In a new type of treatment, hydrogen gas administered in drinking water has been shown to neutralize ROS, reducing rheumatoid arthritis symptoms. That said, the gas is not particularly soluble in bodily fluids, plus it's quickly eliminated from the body.
Given those limitations, scientists from China's Southern Medical University set out to develop a method of delivering the gas directly to arthritic joints, and keeping it there for a sustained period. The researchers started with commercially available magnesium microspheres, which they mostly coated with a joint lubricant called hyaluronic acid – one spot on each sphere was left uncoated, however.
When the microspheres were subsequently placed in simulated joint fluid, the uncoated magnesium on each sphere reacted with the water in that fluid, producing a stream of hydrogen gas bubbles. Those bubbles actually acted as a form of propulsion, causing the spheres to move about within the fluid. For this reason, the coated microspheres are described as "micromotors."
It is now hoped that the micromotors could one day be injected directly into patients' arthritic joints – the spheres would proceed to move throughout the joint, simultaneously releasing hydrogen gas and hyaluronic acid over a prolonged period of time.
In fact, in lab tests performed on the joints of arthritic rats, injection of the micromotors was shown to reduce swelling of the paws, bone erosion and cytokine levels, as compared to an untreated control group.
The research is described in a paper that was recently published in the journal ACS Nano Letters.