Depression is often found in patients that suffer from chronic pain. In fact, that percentage ranges from 30% to 50%. It has also been shown that the Nrf2 is decreased in patients that suffer from depression. Nrf2 is the "master regulator" of the antioxidant system which regulates over 200 genes. These genes include those for neutralizing oxidative stress, mitochondrial biogenesis and adipogenesis. In addition, it has been found that it plays an inhibitory role in inflammation.
The Nrf2 system can be activated by a number of food supplements and natural compounds. Past studies have demonstrated that sulforaphane, a compound found in broccoli and cabbage, had beneficial effect on inflammation-induced depression. Also, it may reduce symptoms of
allodynia and
hyperalgesia which are two symptoms common in fibromyalgia and pain conditions. In a rat model of neuropathic pain (spinal nerve injury) in a new 2018 study, researchers demonstrated that the animals exhibited nociceptive damage and
anhedonia-like phenotypes. They also found lower levels of Nrf2 in the spinal cord and livers of these animals. Treatment with sulforaphane before injury resulted in amelioration of anhedonia-like behaviors and reduced lower levels of Nrf2 in the brain and spinal cord in rats with anhedonia-like phenotypes. Treatment after injury demonstrated significantly higher levels of Nrf2 and a decrease in mechanical withdrawal threshold score. This was the first study to show that Nrf2 impacts anhedonia after neuropathic pain and that sulforaphane may be therapeutic in depression when associated with neuropathic pain. (1)
1. Role of Keap1-Nrf2 Signaling in Anhedonia Symptoms in a Rat Model of Chronic Neuropathic Pain: Improvement With Sulforaphane. Frontiers in pharmacology, Vol. 9 (2018) by Shan Li, Chun Yang, Xi Fang, et al. https://www.frontiersin.org/articles/10.3389/fphar.2018.00887/full
