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Light and electron microscopic studies on rat arterial lesions induced by experimental arterial contraction
Abstract:
Experimental contraction was produced in the rat mesenteric arteries and the arterial segments were studied morphologically. When the rat mesenteric artery was exposed in physiological saline solution at 37 degrees C and 2-3 mg of methoxamine hydrochloride (10 mg/ml) was dripped onto it, intense contraction was observed for about 30 min but elevation in blood pressure was slight. During the contraction, numerous vacuoles were seen in the medial smooth muscle cells of the arterial segments, and these vacuoles were shown electron microscopically to have double unit membranes, indicating that they were formed by herniation of a part of the adjacent smooth muscle cell body. In the arteries 1-6 h after the end of the contraction, cellular, nuclear and vacuolar membranes and myofilaments of the medial muscle cells were partially lost. 12-24 h after the contraction the arteries exhibited necrosis and desquamation of endothelial cells and platelet adhesion. In the media, smooth muscle cells were completely deprived of cell membranes, myofilaments, nuclei, intracytoplasmic organelles other than mitochondria, and vacuolar membranes. The cytoplasm was filled with fine granular and granulo-vesicular material, and fibrin insudation was observed in these severely damaged cells. Arterial contraction may be an important factor in the induction of arterial lesions.
Insights
Experimental contraction of rat mesenteric arteries induced significant cellular damage, including membrane loss and necrosis. This suggests that intense arterial contraction may play a role in developing arterial lesions.
Area of Science:
- Vascular Biology
- Pathology
- Cell Biology
Background:
- Rat mesenteric arteries are a model for studying vascular responses.
- Methoxamine hydrochloride is a vasoconstrictor used to induce experimental contraction.
Purpose of the Study:
- To investigate the morphological changes in rat mesenteric arteries following experimental contraction.
- To determine the role of arterial contraction in the induction of arterial lesions.
Main Methods:
- Experimental contraction induced in rat mesenteric arteries using methoxamine hydrochloride.
- Morphological and electron microscopic examination of arterial segments at various time points post-contraction.
Main Results:
- Intense contraction led to vacuole formation in medial smooth muscle cells.
- Significant loss of cellular structures, including membranes and myofilaments, occurred within 1-6 hours.
- Necrosis, endothelial cell desquamation, and platelet adhesion were observed 12-24 hours post-contraction.
Conclusions:
- Severe cellular damage and arterial lesions were observed following experimental contraction.
- Arterial contraction is implicated as a potential factor in the induction of arterial lesions.