Lipid peroxidation as a cause of ageing and injury of cells is –
**Core Concept**
Lipid peroxidation is a process in which free radicals attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids (PUFAs), leading to cell damage and aging. This occurs due to the imbalance between the production of reactive oxygen species (ROS) and the body's ability to detoxify these harmful compounds.
**Why the Correct Answer is Right**
Lipid peroxidation is initiated by the interaction of ROS with PUFAs, resulting in the formation of lipid peroxides. This process leads to the propagation of the free radical chain reaction, causing damage to cellular membranes and proteins. The enzyme glutathione peroxidase plays a crucial role in reducing lipid peroxides to their corresponding alcohols, thereby preventing further damage. The accumulation of lipid peroxides and their derivatives contributes to aging and cell injury.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not directly related to lipid peroxidation. While oxidative stress is a broader concept, it encompasses lipid peroxidation as one of its mechanisms.
**Option B:** Incorrect because it is more related to the inflammatory response, which is a consequence of lipid peroxidation, rather than a cause.
**Option C:** Incorrect because it is a consequence of lipid peroxidation, not a cause. Lipid peroxides can lead to the formation of advanced oxidation protein products (AOPPs), which contribute to cellular damage.
**Clinical Pearl / High-Yield Fact**
Lipid peroxidation is a key mechanism by which oxidative stress causes cellular damage. It is essential to maintain the balance between ROS production and detoxification to prevent lipid peroxidation and its associated consequences.
**Correct Answer:** D.