Injections of drug-filled nanoparticles may relieve arthritis pain

Drug delivery can be nanoparticles. Help treat osteoarthritis. In mice with symptoms of the condition, an injection of the particles relieved pain for months.

Osteoarthritis is the most common form of arthritis, affecting about 530 million people worldwide. This happens when Cartilage Cushion bones break down, causing joint stiffness and pain. Treatments for the condition are limited, and none of them can stop Degeneration of cartilage.

Previous research has shown that a drug called pazopanib can help relieve osteoarthritis pain. However, its effects only last for a few days. So Hee-Jeong Im Sampen at the University of Illinois at Chicago and colleagues developed a method of administering it that prolongs its release.

The researchers encapsulated pazopanib inside nanoparticles designed to break down in the body and slowly release the drugs they carry into nearby tissues. The nanoparticles the team used have already been approved by the US Food and Drug Administration to deliver other drugs. They then injected the nanoparticles into the knees of 16 mice, half of which had early signs of osteoarthritis and the other half had advanced symptoms. A similar number of animals received dummy injections of nanoparticles without pazopanib.

Arthritis is difficult to assess in animals, so the researchers instead focused on the sensitivity of mice, using the widely accepted idea that when an individual experiences pain – such as joints I Pain – They are also more sensitive to physical touch.

Immediately after the treatment, the scientists measured how quickly the mice removed one of their paws from an uncomfortable hot plate. Mice with early or advanced osteoarthritis took significantly longer to remove the paw if they had received pazopanib instead of a dummy injection, suggesting that the pazopanib nanoparticles would have relieved their joint pain more quickly. are When the researchers repeated the hot plate test later — two months later for the advanced osteoarthritis group and three months later for the early osteoarthritis group — they found a similar effect. This means that pazopanib nanoparticles effectively provide pain relief for several weeks. Animals treated with pazopanib also had less cartilage degeneration, indicating that the nanoparticles could slow the progression of osteoarthritis.

Even so, Sempen says, just because a treatment is effective in mice doesn’t mean it will be in humans. The researchers plan to explore other ways in which pazopanib’s pain-relieving properties can be assessed in animals. One way would be to analyze gait and limb use to confirm that the drug relieves joint pain, the researchers said.