Total salvianolic acid improves ischemia-reperfusion-induced microcirculatory disturbance in rat mesentery.

AIM: To investigate the effect of total salvianolic acid (TSA) on ischemia-reperfusion (I/R)-induced rat mesenteric microcirculatory dysfunctions. METHODS: Male Wistar rats were randomly distributed into 5 groups (n = 6 each): Sham group and I/R group (infused with saline), TSA group, TSA + I/R group and I/R + TSA group (infused with TSA, 5 mg/kg per hour). Mesenteric I/R were conducted by a ligation of the mesenteric artery and vein (10 min) and subsequent release of the occlusion. TSA was continuously infused either starting from 10 min before the ischemia or 10 min after reperfusion. Changes in mesenteric microcirculatory variables, including diameter of venule, velocity of red blood cells in venule, leukocyte adhesion, free radicals released from venule, albumin leakage and mast cell degranulation, were observed through an inverted intravital microscope. Meanwhile, the expression of adhesion molecules CD11b/CD18 on neutrophils was evaluated by flow cytometry. Ultrastructural evidence of mesenteric venules damage was assessed after microcirculation observation. RESULTS: I/R led to multiple responses in mesenteric post-capillary venules, including a significant increase in the adhesion of leukocytes, production of oxygen radicals in the venular wall, albumin efflux and enhanced mast cell degranulation in vivo. All the I/R-induced manifestations were significantly reduced by pre- or post-treatment with TSA, with the exception that the I/R-induced increase in mast cell degranulation was inhibited only by pre-treatment with TSA. Moreover, pre- or post-treatment with TSA significantly attenuated the expression of CD11b/CD18 on neutrophils, reducing the increase in the number of caveolae in the endothelial cells of mesentery post-capillary venules induced by I/R. CONCLUSION: The results demonstrated that TSA protects from and ameliorates the microcirculation disturbance induced by I/R, which was associated with TSA inhibiting the production of oxygen-free radicals in the venular wall and the expression of CD11b/CD18 on neutrophils.

Carrageenan plasma expander: effect on mesenteric ischemia-reperfusion injury in the rat.

The effect of carrageenan against ischemia-reperfusion injury was investigated. Rats were grouped into four, subjected to 10 min of ischemia and reperfusion in their mesenteric venules and 30% of their blood volume was replaced with either normal saline solution, dextran 70 in 5% dextrose, or iota-carrageenan solution, while the fourth group remained untreated. Parameters such as venule diameter, red blood cell velocity, leukocyte rolling and adhesion, were then observed by video. Findings reveal that carrageenan infusion has the tendency to attenuate leukocyte rolling and adhesion, increase venule diameter and regain erythrocyte velocity after ischemia. The data suggest that the effects of carrageenan were comparable to that of either of the more commercially used plasma expanders, dextran 70 or normal saline solution. Overall, however, these did not differ significantly from the untreated rats.

Role of Kupffer cells in iodized oil embolization.

RATIONALE AND OBJECTIVES: Iodized oil is a common oily embolic agent used in chemoembolization for treating hepatic tumors. However, how the iodized oil is cleared from the liver has been an unsettled and controversial issue. In this study, the authors attempt to clarify whether Kupffer cells are involved in the clearance of iodized oil and to evaluate the effect of hepatic arterial injection of iodized oil on the functional status of Kupffer cells. METHODS: Iodized oil was injected into the proper hepatic artery in 42 Fischer 344 rats. In vivo microscopy was performed immediately after and 1, 3, 7, 15, 30, and 60 days after injection. Electron microscopy was performed after in vivo microscopy. RESULTS: Kupffer cells actively captured and phagocytosed iodized oil droplets in the hepatic circulation. The number and functional status of Kupffer cells in the liver were significantly increased after the injection of the iodized oil and returned to normal when the liver was cleared of the oil. CONCLUSIONS: Kupffer cells play an important role in clearing iodized oil from the liver. Iodized oil activates the immune defense system in the liver, which may have a synergistic effect in tumor treatment.

Fine structural characteristics of neurophysin-positive perivascular plexus that develop in the rat hypothalamus following interruption of the hypothalamo-neurohypophysial tract.

Transection of neurosecretory axons of the hypothalamo-neurohypophysial tract within the hypothalamus by stereotactic grafts of various tissues or knife cuts induced the development of neurophysin-positive plexus around arterioles, venules and capillaries in the vicinity of these grafts or cuts. These plexus ranged from single axons to densely woven networks and tended to increase progressively with time after experimental intervention. At the fine structural level, typical neurosecretory axon profiles were either abutting the perivascular connective tissue space or located within it. They were usually accompanied by astrocyte processes or microglial cells. Many of these axons had extensive contact with the surrounding basal lamina at which point clusters of microvesicles reminiscent of axon terminals in the neural lobe were present.

Endothelial changes and microvascular leakage due to hyperthermia in chick embryos.

The effects of hyperthermia on the developing 2- and 3-day chick embryo were studied by vital microscopy, in vivo microangiography and electron microscopy of post-capillary venules of the pellucid area of the yolk sac. Hyperthermia of 3 degrees C and 4 degrees C produced significant microvascular changes and perivascular oedema. The microvascular defects were characterized by interruption of the endothelial lining and the presence of blood cells breaking through the vessel walls. In addition, there were numerous inter-endothelial gaps with wide subendothelial spaces. Microangiography showed leakage from the vessel walls. It is concluded that hyperthermia produces vessel wall injury and induces the formation of gaps between endothelial cells resulting in extravasation of plasma and blood cells. These gaps are similar to those produced by biochemical mediators of inflammation. It is suggested that these microvascular changes with pathological leakage may play important roles in abnormal vascular and embryonic development.

[Several details of the ultrastructural organization of the blood-brain barrier in humans and animals]. / Nekotorye detali ul'trastrukturnoi organizatsii gemato-éntsefalicheskogo bar'era u cheloveka i zhivotnykh.

Electron microscope study of capillaries, arterioles, and venules of the cerebral cortex, strio--pallidar and nonneurosecretory complexes of hypothalamus of the man, cat, and rat revealed some details of the structure of the basal membrane and its interrelationship with adjacent astrocyte processes. Specific tight--junction type was present constantly among the adjacent membranes of glial cells. The system of the specializations and basal membrane seems to exert regulatory influence upon functioning of the blood--brain barrier.