Perfection in Every Injection — Precision Tail Vein Injection for Preclinical Research

PERFECTION

IN EVERY

INJECTION

INJ Systems manufactures precision-engineered tail vein injection restrainers for laboratory mice in preclinical research. The product line includes two devices: the INJ ECG Tail Injector, which mounts directly onto ECG imaging platforms such as the VisualSonics Vevo series for IV injection during cardiac imaging, and the INJ Bench Tail Injector Restrainer, a standalone benchtop unit for awake mice. Both feature an integrated narrow LED strip that illuminates the lateral tail vein for accurate needle placement, support 27–30 gauge needles, and use a voluntary self-entry tunnel that eliminates scruffing. Across more than 10,000 documented procedures at 50+ research laboratories worldwide, INJ Systems devices report a 98% injection success rate.

INJ improves accuracy through three coordinated design elements. First, an integrated narrow LED strip backlights the lateral tail vein, providing the contrast needed to see the vessel clearly — particularly in dark-pigmented strains such as C57BL/6 mice where the vein is otherwise difficult to visualize. Second, a self-entry tunnel stabilizes the animal without scruffing or restraint stress, which would otherwise cause vasoconstriction and collapse the vein. Third, the tail groove holds the tail in a fixed, repeatable position so the operator can insert a 27–30G needle bevel-up at a shallow, consistent angle. Together these reduce operator variability and contribute to the 98% success rate observed across 10,000+ procedures.

The INJ ECG Tail Injector is engineered specifically for the VisualSonics Vevo series, which is the dominant small-animal echocardiography platform in preclinical cardiology research. It is the first tail vein injection restrainer designed to mount directly onto the ECG plate, allowing IV administration without removing the animal from the imaging stage or interrupting the cardiac imaging workflow. The Bench model is platform-independent and works on any flat surface. Compatibility with other ECG imaging systems can be evaluated on request — contact sales@injsystems.com with your platform model for confirmation.

The system is optimized for mice and can be adapted for small rats with minor adjustments. For mice it has been validated across common strains used in preclinical research, including C57BL/6 (where the integrated LED illumination is particularly important for vein visualization), BALB/c, and most outbred lines. The tail groove and restraint geometry are sized for adult mice; very young or very large animals may require alternative protocols. Contact sales@injsystems.com to discuss strain or size considerations specific to your study.

No specialized training is required. The intuitive design — voluntary tail-first entry, fixed tail groove, and LED-illuminated vein — significantly shortens the learning curve compared with manual restraint and overhead-lit tail vein injection. New operators typically reach consistent results within a small number of practice attempts, and experienced operators report faster procedure times once the device is set up. A short setup-and-use overview is included with each unit; on-site or remote walkthrough is available on request.

Yes. Components are made from durable materials. The system is reusable after proper cleaning with Ethanol.

A narrow adjustable LED strip runs along the tail holder, illuminating the vein for precise needle guidance under both bright and dim lab conditions.

Absolutely. INJ works seamlessly with gas anesthesia systems in preclinical imaging setups.

Yes, the INJ system can be used as a standalone injection aid on any flat surface. However, it is optimized for ECG imaging plates.

INJ sets itself apart with precise alignment, adjustable lighting, tail stabilization, and full ECG platform compatibility — ensuring accurate injections during imaging.

C57BL/6 mice have dark skin pigmentation that reduces vein visibility under standard lighting. The key steps are: warm the tail for 5–10 minutes to dilate the veins, use low-angle or specialized LED illumination to create contrast between the vein and surrounding tissue, stabilize the tail firmly to prevent rotation, and insert a 27–30G needle bevel-up at a shallow angle. The INJ system's integrated narrow LED strip significantly improves vein visualization in black mice compared to overhead room lighting.

For mice, 27–30 gauge needles are standard. A 27G needle is appropriate for most injections and larger volumes. For smaller mice or when using minimal volumes, 28G–30G needles reduce tail trauma. Use a syringe of up to 1 mL. The INJ system is designed to support 27–30G needles and includes a dedicated catheter holder to stabilize the line after insertion.

Warming promotes vasodilation and makes the lateral tail veins easier to see and access. Options include: a heating pad set to 37–40°C, a warming box or lamp for 5–10 minutes pre-procedure, or warm water applied briefly to the tail. Avoid overheating — excessive temperatures cause stress and can harm the animal. Most ECG imaging platforms include built-in heating systems; ensure the animal is at maintenance anesthesia (1.5–2% isoflurane) before attempting injection, as high induction concentrations lower blood pressure and collapse the vein.

Both routes deliver compounds into systemic circulation, but they differ in precision and animal welfare. Retro-orbital (r.o.) injection targets the venous sinus behind the eye — a larger target, but highly operator-dependent, with risk of ocular damage and undetected extravasation. Tail vein injection allows direct visualization of the entry point and is well-suited for repeated injections with minimal tissue trauma. Studies show similar pharmacokinetic profiles between the two routes. For high-volume, repeated, or imaging-concurrent studies, tail vein injection with a proper restrainer and LED illumination is generally preferred for reproducibility and animal welfare.