1- 3, 6, 9, 14- 17, 21- 23 One study compared hematologic parameters in blood collected from the sublingual vein and vena cava in rats, and equivalence was only established for 5 of 14 hematologic parameters. Hematologic and biochemistry parameters in mice and rats can vary when blood is obtained from different sampling sites. 20 Although sedation or anesthesia is required for using the gingival vein, its safety, feasibility, and potential for large sample volume make it a promising new venipuncture site in guinea pigs. 20 In addition, histologic analyses confirmed that multiple blood collections over time were minimally traumatic to the surrounding tissue. Samples were collected weekly from each guinea pig for 6 wk, and no significant alterations in hematologic parameters were noted. 7 A recent study 20 determined that a maximum of 500 μL of blood could be collected from guinea pigs by using this route. As much as 800 μL of blood in rats and 100 μL in mice were successfully acquired with minimal signs of pain and distress after collection. The gingival vein was first reported as a simple and reliable intravascular injection and blood collection site in rats and mice.
The gingival vein ( labialis mandibularis vein) is located within the gingiva just below the pair of mandibular incisors.
Therefore, cranial vena caval venipuncture requires anesthesia to ensure precise sampling. Although the cranial vena cava is frequently used, its proximity to the heart and major vessels within the thoracic cavity poses a significant risk of death due to traumatic intrathoracic or pericardial hemorrhage. Manual restraint can be extremely stressful to guinea pigs, and sedation or anesthesia is often necessary. 19, 27 However, due to guinea pigs’ short and thick neck, the jugular vein is difficult to palpate and visualize. The jugular vein and cranial vena cava are the most commonly used sites to collect large blood samples (1 to 2 mL). 8, 19, 27 Therefore, blood may need to be collected from multiple peripheral veins to acquire a sufficient sample volume. 4 However, these vessels are small, and minimal blood (less than 200 μL) can be collected from each vein. 4, 8, 19, 29 The lateral saphenous, cephalic, and auricular veins are easily accessible, allow for repeated sampling, and do not require anesthesia. Common venipuncture sites include the lateral saphenous vein, 4, 8, 11, 19, 29 cephalic vein, 8, 19, 29 auricular vein, 4, 29 cranial vena cava, 8, 19, 29 and jugular vein. Compared with other rodents, safe and easily accessible blood collection techniques in guinea pigs are limited due to their compact neck, short limbs, and lack of a tail.Ī myriad of venipuncture techniques with variable blood sample volumes has been described in guinea pigs. 10, 18, 26, 27 Venipuncture is an essential procedure in research studies using animal models but is often challenging to perform in guinea pigs. 10, 18 These similarities, combined with a docile nature and small size, have made the guinea pig a particularly useful animal model of human diseases for more than 200 y. Guinea pigs share many biologic similarities to humans, including their dietary requirement for vitamin C and immune responses to various infectious diseases. These results provide evidence that gingival venipuncture can be used as an alternative blood collection method for guinea pigs for hematologic analysis but should not be used for blood culture. No clinical signs of hemorrhage or trauma were detected at either site. Bacteria did not grow from any cranial vena caval blood samples prepared with dilute chlorhexidine. Bacterial growth occurred in all 5 gingival vein blood samples prepared by using saline and 2 of the 5 prepared with dilute chlorhexidine. Bland–Altman analyses calculated a small mean bias for all hematologic parameters, indicating clinical interpretation is unlikely to be affected by the sampling site. Only MCV was significantly different between sampling sites. Blood samples were obtained from both the gingival vein and cranial vena cava of anesthetized Dunkin Hartley guinea pigs for CBC ( n = 9) and aerobic blood cultures ( n = 10).
The purpose of this study was to determine whether the gingival vein can be used as an alternative blood collection site in guinea pigs, such that: (1) hematologic parameters would be consistent with samples collected from the cranial vena cava and (2) no contaminants from the oral cavity would be introduced into the sample. Gingival venipuncture is a recently described blood sampling technique that is minimally traumatic with no significant alterations in hematologic parameters when multiple blood samples were collected weekly for 6 wk. Blood collection methods in guinea pigs are limited due to the animals’ compact neck, short limbs, and lack of a tail.