6-ketoprostaglandin-f1-alpha and monocrotaline-pyrrole

Monocrotaline (MCT)-induced vascular injury in liver and lung may be caused by interaction of MCT metabolites such as monocrotaline pyrrole (MCTP) with vascular cells. Responses of bovine and porcine pulmonary artery endothelial cells (BECs and PECs, respectively) to a single administration of MCTP were compared. MCTP caused a delayed and progressive release of lactate dehydrogenase (LDH) activity from BECs and a gradual decrease in monolayer cellularity. Surviving cells became markedly hypertrophic. PECs were less sensitive to the cytolytic effects of MCTP, showing minimal cell detachment and little release of LDH activity. However, monolayer cellularity, as assessed by PEC enumeration, decreased in a dose-dependent manner. Hypertrophy of surviving PECs was less pronounced than in BECs. MCTP caused enhanced release of prostacyclin from monolayers of BECs and PECs exposed to 10 micrograms MCTP/ml, and concentrations of 0.5 microgram/ml or greater caused equivalent reduction in colony-forming efficiency in both cell types. In summary, whereas BECs were more susceptible to the cytolytic and hypertrophic effects of MCTP, BECs and PECs responded similarly with regard to prostacyclin release and were equally sensitive to the cytostatic effects of this compound.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Cattle; Cells, Cultured; Colony-Forming Units Assay; Endothelium, Vascular; L-Lactate Dehydrogenase; Lung; Monocrotaline; Swine

Monocrotaline pyrrole (MCTP), a reactive electrophile, induces delayed and progressive pulmonary edema, vascular remodeling, and pulmonary hypertension after a single intravenous administration to rats. The effects of a single exposure of cultured bovine pulmonary artery endothelial cells (BEC) and bovine pulmonary artery smooth muscle cells (BSMC) to MCTP were examined. Monocrotaline pyrrole caused a dose-dependent, delayed, and progressive cell detachment and release of lactate dehydrogenase activity from monolayers of BECs but not BSMCs. Monolayers of BECs also released increased concentrations of 6-keto-prostaglandin F1 degrees, the stable metabolite of prostacyclin, as the post-treatment interval increased. Progressive and marked endothelial cell hypertrophy occurred after exposure to a nominal concentration of 5 or 50 micrograms/ml of MCTP but not after 0.5 micrograms/ml. Morphologic changes in monolayers of BSMCs were minimal, even up to 2 weeks after exposure. Ultrastructurally the hypertrophic, MCTP-treated BECs had enlarged cell profiles with enlarged nuclei. The nucleoli were prominent, occasionally multiple, and had separation of granular and fibrillar components. Cytoplasmic microtubules and perinuclear intermediate filaments were prominent in some cells, as were the golgi apparatus and endoplasmic reticulum. Degenerative changes were not prominent in cells that remained in the monolayer. Monocrotaline pyrrole inhibited proliferation of both cell types at concentrations (0.5 micrograms/ml) that were not cytotoxic. These findings indicate that MCTP induces direct, dose-dependent injury to cells in culture that is delayed and progressive, and the expression of this injury depends, in part, on the cell type.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Cattle; Cells, Cultured; Endothelium, Vascular; L-Lactate Dehydrogenase; Microscopy, Electron; Monocrotaline; Muscle, Smooth, Vascular; Pulmonary Artery; Pyrrolizidine Alkaloids; Stem Cells

Monocrotaline pyrrole (MCTP) causes pulmonary vascular injury and pulmonary hypertension in rats. Although the mechanism by which MCTP causes pulmonary hypertension is unknown, vasoconstriction may play a role. Thromboxane (Tx) A2 is a vasoconstrictor released from platelets and other blood cells. Following treatment with MCTP in vivo, the release of stable metabolites of TxA2 and prostacyclin [TxB2 and 6-keto prostaglandin F1 alpha (6-keto-PGF1 alpha), respectively] was determined in isolated lungs perfused with blood. Early in the development of pulmonary hypertension, the concentrations of TxB2 and 6-keto-PGF1 alpha in the effluent plasma of lungs from treated rats were not different from control rats. When pulmonary hypertension was well established, the concentration of TxB2 was higher in the effluent plasma of lungs from MCTP-treated rats, although the concentration of 6-keto-PGF1 alpha was not affected by treatment.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Hypertension, Pulmonary; Lung; Male; Monocrotaline; Pyrrolizidine Alkaloids; Rats; Thromboxane B2