The Radnoti isolated blood vessel perfusion system is designed to permit the researcher to measure the contractile responses of blood vessel segments in a temperature controlled environment. Blood vessels, or other tubular muscular structures such as small sections of intestine, are mounted on a pair of glass cannula that pass through the cap of the bath. There is one straight cannula and one J-shaped cannula per set; the vessel is attached over the end of the J-shape and connected to the straight cannula, thus forming a loop through which the vessel can be perfused. By perfusing the vessel at a set rate, changes in vessel diameter can be detected by pressure changes registered by in-line pressure transducers. The mounting cannula are set in position to accommodate the vessel’s length by positioning the cannula using the screw locks built into the cap of the bath, inserting the ends of the vessel over the end of each cannula and tying the vessel onto position. The cap also has platinum field electrodes positioned on either side of the vessel, permitting electrical stimulation of the muscle. The cap with attached vessel is then inserted into the temperature controlled bath.
The bath has access ports that permit exchange of the bath fluid, either continuously or as discrete washes. Therefore, the vessel can be perfused internally and externally with similar or different fluids (even at different temperatures) and the fluids can be collected on a continual basis, if desired. The fluids can also be gassed independently, allowing the researcher to create different internal and external aerobic environments
Radnoti Glass Technology has developed a special perfusion system to meet the needs of scientists interested in blood vessel research in the rapidly advancing areas of endothelial function, metabolism and release of endogenous neurotransmitters and vasoactive substances.
This system includes a Radnoti 25ml organ bath, which has a perfusate pre-warming coil built into the bath’s water-jacket. The solution exits through a glass Luer fitting before passing into the entry cannula through connecting tubing. The use of Luer fittings on the entry and exit of the pre-warming coil permit the system to be coupled to another perfusion system to form a cascade system (see Box).
This configuration also allows placement of a pressure transducer and permits addition or removal of perfusion media before it reaches the blood vessel. The perfusion system also has a replaceable aerator with adjustable needle valve, a bottom drain and overflow outlet. The perfusion system cap is made of high-density polypropylene with an O-ring seal to insure a snug fit. The cap has five holes drilled through it for passage of a set of stimulating electrodes and an inflow and outflow cannula, between which the blood vessel is mounted, and a tube for sample addition to the bath interior. All of the items inserted into the cap can be positioned through the use of nylon set screws.
To use this perfusion system, the blood vessel of choice is dissected out and cleaned. The vessel is then secured to the inflow and the outflow cannula by means of a suture. The inflow cannula is straight while the outflow has a hooked end to facilitate proper vessel alignment. The ends of the cannula are both slightly flared with a fine ground finish to insure a secure fit to the blood vessel.
Standard cannula O.D.’s are 1.0, 1.5, 2.0, 2.5 and 3.0mm which will accommodate various preparations such as rat tail artery, portal vein, pulmonary aorta, and the mesentery or isolated large vessels. Additional sizes are available upon request. This design incorporates an open-end perfusion system for the study of vasoconstrictors and vasodilators, nerve stimulation, and the effect of various drugs on an entire vascular bed in-vitro.
Stimulating electrodes are positioned in the tissue to promote the release of neurotransmitters. When mounting the tissue, the electrodes are slid upward and secured with set screws, providing clear access to the cannula. Once the tissue is secured, the electrodes are repositioned. The bath media can be rapidly exchanged through the use of the bottom drain or the overflow outlet and solutions added via pipette, syringe or external reservoir.
The vessel section is cannulated with one of a set of cannula and placed in a water-jacketed bath that can be aerated. In the constant pressure mode, a reservoir (or bubble trap) is placed above the bath at a given hydrostatic head and flow is changed by the contraction or dilation of the vessel. Flow measurements are made using drop counters, flow meters or other devices. In the constant flow mode, a peristaltic or syringe pump delivers fluid at a predetermined rate. In-line pressure transducers measure changes in diameter via changes in pressure.
In the constant flow system, drugs may be infused into the system via syringe pumps. In both modes, the media outside the vessels can be changed independently of the media perfused through the vessels. It is also possible to directly measure the diameter of the vessel using a camera. Note that in certain cases an aquarium pump can be used to aerate tissues with low oxygen requirements in non-bicarbonate buffer systems, thereby eliminating the problems and expense of gas tanks and regulators.
Instrumentation included in the Four Channel system includes: 4 pressure transducers, a peristaltic pump, reservoirs, bubble traps, recirculating bath, and all associated tubing and connectors. The Single Channel system does not include pumps, or recirculating bath. Available options: Indwelling electrodes for tissue stimulation, a tissue stimulator, flow meters, or other fluid measuring devices, camera, air pump, and data acquisition with automation.
The Blood Vessel Perfusion System is available in two sizes:
158700-1 Single Channel Blood Vessel Perfusion System
158700-4 Four Channel Blood Vessel Perfusion System