Anti-inflammatory action of steroids due to
**Core Concept**
The anti-inflammatory action of steroids is primarily attributed to their ability to decrease the transcription of pro-inflammatory genes, thereby reducing the production of inflammatory mediators. This effect is mediated through the interaction of steroids with specific transcription factors, such as nuclear factor kappa B (NF-κB).
**Why the Correct Answer is Right**
Steroids exert their anti-inflammatory effects by binding to cytoplasmic glucocorticoid receptors. This binding causes a conformational change in the receptor, allowing it to translocate to the nucleus, where it binds to specific DNA sequences, known as glucocorticoid response elements (GREs). This interaction suppresses the transcription of pro-inflammatory genes, including those encoding cytokines, chemokines, and other inflammatory mediators. The resulting decrease in inflammatory mediator production leads to a reduction in inflammation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because steroids do not directly inhibit the activity of enzymes involved in the production of inflammatory mediators. While steroids may indirectly affect enzyme activity by reducing the transcription of pro-inflammatory genes, this is not the primary mechanism of their anti-inflammatory action.
**Option B:** This option is incorrect because steroids do not act by directly scavenging reactive oxygen species (ROS). While ROS can contribute to inflammation, the anti-inflammatory effects of steroids are primarily due to their transcriptional regulation of pro-inflammatory genes.
**Option C:** This option is incorrect because steroids do not act by directly inhibiting the activity of the enzyme cyclooxygenase (COX). While COX inhibitors can reduce the production of prostaglandins, a type of inflammatory mediator, this is not the primary mechanism of action of steroids.
**Clinical Pearl / High-Yield Fact**
Steroids are often used in the treatment of inflammation due to their potency and rapid onset of action. However, their use should be judicious, as long-term steroid use can lead to significant side effects, including adrenal suppression, osteoporosis, and glaucoma.
**Correct Answer: D. Transcriptional regulation of pro-inflammatory genes.**