June 17, 2022 – In a surprising discovery that flies against conventional medicine, researchers at McGill University report that treatment of pain with anti-inflammatory drugs, such as ibuprofen or aspirin, can promote pain in the long run.
The document published in Science Translational Medicinesuggests this inflammation, a normal part of recovery from injury, helps resolve acute pain and prevents it from becoming chronic. Blocking this inflammation can interfere with this process, leading to more difficult to treat pain.
“What we’ve been doing for decades not only looks wrong, it’s 180 degrees wrong,” said senior research author Jeffrey Mogil, Ph.D., a professor in the McGill Department of Psychology. “You don’t have to block inflammation. You need to let the inflammation happen. This is what stops it chronic pain. ”
Inflammation: a painkiller by nature
Wanting to understand why the pain disappears for some but lingers (and continues) for others, the researchers looked at the mechanisms of pain in both humans and mice. They found that a type of white blood cell known as neutrophil appears to play a key role.
“In analyzing the genes of people suffering from backache“We’ve seen active changes in genes over time in people whose pain is gone,” he said. Luda Diatchenko, Doctor, Professor at McGill School of Medicine and Canadian Research Department of Human Pain Genetics. “Changes in blood cells and their activity seemed to be the most important factor, especially in cells called neutrophils.”
To test this relationship, the researchers blocked neutrophils in mice and found that the pain lasted 2 to 10 times longer than normal. Anti-inflammatory drugs, while providing short-term relief, have the same effect of prolonging pain – although injecting neutrophils into mice seems to prevent this.
The findings are supported by a separate analysis of 500,000 people in the UK, which shows that those who take anti-inflammatory drugs to treat their pain are more likely to have pain 2 to 10 years later.
“Inflammation occurs for some reason,” says Mogil, “and it seems dangerous to interfere with it.”
Rethinking how we treat pain
Neutrophils arrive early during inflammation, at the beginning of the injury – just when many of us reach for pain medications. This study suggests that it may be better swimming to block inflammation instead of letting neutrophils “do their thing”. Taking an analgesic that relieves pain without blocking neutrophils, e.g. acetaminophenmay be better than taking an anti-inflammatory drug or steroidssays Mogil.
And yet, while the findings are convincing, clinical trials are needed to directly compare anti-inflammatory drugs with other painkillers, the researchers said. This study could also lay the groundwork for developing new drugs for patients with chronic pain, Mogil said.
“Our data clearly show that neutrophils act like analgesics themselves, which is potentially beneficial for the development of analgesics,” says Mogil. “And of course, we need new analgesics.”