Reported analgesic administration to rabbits undergoing experimental surgical procedures

Background  

It has become widely accepted that whenever animals are used in scientific procedures, the 3Rs principle of replacement, reduction and refinement described by William Russell and Rex Burch should be adhered to. Animals should be replaced with non-sentient alternatives if possible, the number of animals used should be reduced and experimental procedures should be refined to minimise pain, suffering and distress. Administration of analgesic agents to animals undergoing surgical procedures is a refinement used to alleviate pain. In this study, a structured literature review was carried out to examine current trends in analgesic administration to rabbits undergoing experimental surgical procedures.     

Experimental congenital syphilis in rabbits

A model for congenital syphilis in rabbits was developed based on multiple intravenous injections of pregnant does with high concentrations of Treponema pallidum. A total of 48 pregnant does and 394 newborns were evaluated. Indications of in utero infection included a 7- to 10-fold increase in fetal mortality and a 49% reduction in birth weight. The size of the stillborns varied. Some developed to normal size, whereas others were poorly developed, hemorrhagic, and 1/10th normal size. Fetuses were surgically removed after 25 to 28 days of gestation and extracts of the fetal tissues were injected into adult rabbits. Syphilitic lesions resulted demonstrating the presence of T. pallidum within the fetal tissues. Treponemes were also demonstrated within splenic tissue from a 1-week-old newborn. Isolated amniotic membranes were placed in Franz Biologic chambers. Viable organisms readily penetrated through the amnion but heat-inactivated organisms did not. Further evidence for in utero transmission of organisms was provided by intradermal injection of 6- to 7-week-old newborns. In control newborns in which the does were not infected during pregnancy, lesions occurred at 90% of the sites injected and developed in typical fashion. In newborns from does infected during pregnancy, lesions occurred in 18% of the sites injected and developed in atypical fashion (flat, nonulcerating, rapid healing). Finally, overt congenital syphilis did not occur if the does were immune prior to pregnancy, then infected with T. pallidum during pregnancy. The percent mortalities and birth weights of newborns were equivalent to control newborns from noninfected does.     

Gene transfer during surgical procedures with molecular surgical suture

Over the last decades, there has been an explosion of interest in plasmid DNA for gene therapy with reports of their efficacy in the fight against cancer, vascular diseases, and inherited diseases caused by specific gene defects (Srivastava, 2003). DNA plasmids present several advantages over the use of recombinant viruses concerning their production and safety issues. Plasmid DNA vectors can be constructed easily and economically, and they are free of size constraints imposed by viral packaging, obviating the need for an infectious vector and lessening the likelihood of toxicity and immunogenicity (Davis, 1993). Plasmids have a relative low cost, long shelf life and allow repetitive administration of the therapeutic gene without generating an immune response against the delivery vector (Donnelly, 2003). Finally, plasmids can be injected directly into tissues, such as heart (Sarkar, 2002), muscle (Neumeister, 2001, Dan, 2000) and tumors (De Marco, 2003, Sasaki, 2002).     

Experimental unilateral coronal synostosis in rabbits

Immobilization of the coronal suture was produced unilaterally in 9-day-old rabbits to determine its effect on subsequent craniofacial development. The suture was immobilized unilaterally by the topical application of methylcyanoacrylate adhesive. Subsequent growth effects on the cranial vault, base, and facial skeleton were assessed by serial radiographic cephalometry. Unilateral coronal suture immobilization resulted in significantly decreased bone growth at the coronal suture (mean 0.95 mm +/- 0.35 SE) when compared to sham-treated control animals (mean 5.06 mm +/- 0.20 SE). Frontonasal suture bone growth contralateral to the immobilized half of the coronal suture, however, was significantly increased. The anterior cranial base became significantly shortened, and orbital asymmetry developed. The pattern of induced abnormalities simulates unilateral coronal synostosis in humans.     

Experimental pulmonary candidiasis in modified rabbits

Pulmonary lesions induced by an intratracheal inoculation of Candida albicans into rabbits in untreated control, bovine serum albumin (BSA)-sensitized and C. albicans-sensitized groups were examined immunohistochemically to clarify the localization of IgG, IgM and C3. In the control group no inflammatory cells were immunoreactive for IgG and only a few macrophages for IgM and C3, whereas in the BSA- and C. albicans-sensitized groups there were a small number of IgG-positive polymorphonuclear leukocytes and IgM- and C3-positive macrophages in the lesions, the latter group being more prominent. Furthermore, epithelioid granulomatous lesions at the late stage in the C. albicans-sensitized animals showed scattered epithelioid cells containing IgG as well as abundant IgG- and IgM-positive plasma cells. These immunohistochemical results were considered to support the estimation that immune complexes contributed to the modification of fungal lesions in the C. albicans-sensitized hosts, although non-immunological defense mechanisms seemed to be more important in the elimination of the fungus.     

不同手术方式对VX2肿瘤侵犯兔下腔静脉预后的影响

目的建立VX2肿瘤侵犯下腔静脉（inferior vena cava,IVC）的动物模型,观察3种不同手术方式对实验动物预后的影响。方法成功建立VX2肿瘤侵犯IVC的动物模型,彩超下证实;将实验动物随机均分为A、B、C三组,分别予以彻底切除IVC和肿瘤、不予重建、彻底切除后人工血管进行重建处理,切下的IVC均送病检。分别于手术后每周彩超观察IVC,出现闭塞的IVC在DSA（digtal subtraction angiography,DSA）下观察侧枝循环建立情况。观察实验动物自然死亡时间,并解剖。结果超声发现3周时所有实验动物均有肿瘤生长（2.75±0.91cm2）,IVC管腔无明显狭窄（2.53±0.23 mm）;DSA显示,人工血管中长期通畅率低,随时间变化实验组可见侧支循环建立和腹壁浅静脉增粗逆流;A、B两实验组生存时间显著高于对照组C组（P1〈0.05;P2=0.036〈0.05）;两实验组中A组生存时间显著高于B组（P3=0.04〈0.05）。两实验组远处转移无差异,均显著低于对照组。结论彻底切除肿瘤可以提高实验动物的术后生存时间和生存率;兔IVC人工血管重建中长期通畅率低,且围手术期死亡率高,生存时间也较不重建组低。     

Mechanical considerations in the design of surgical reconstructive procedures

Tendon transfers are used to restore arm and hand function after injury to the peripheral nerves or after spinal cord injury. Traditional guidelines to choose the length at which the transferred muscle should be attached have a poor scientific foundation. We postulate that passive tension only becomes significant at relatively long lengths and that passive tension as the major factor in intra-operative decision making may result in overstretch of the muscle-tendon unit (MTU) and accompanying low-active force generation. It appears unwise to rely on unknown factors, such as slippage or stress relaxation, to correct an overstretched transfer. Instead, we suggest the use of intra-operative sarcomere length measurements to predict and set the optimal MTU length during reconstructive upper limb surgery.     

Experimental zygomycosis in rabbits: Clinicopathological studies

Zygomycosis was produced experimentally in 20 New Zealand white rabbits (Oryctolagus cuniculus) by intra-nasal administration of spores of Absidia corymbifera. Infected animals showed dullness, depression, coughing and mucopurulent nasal discharge, but no mortality. Haematology revealed no significant change in Hb and PCV, but leukocytosis due to neutrophilia in the initial stages of the experiment. There was a significant increase in serum total proteins, creatinine, AST, ALT, total Igs and CICs. A. corymbifera specific IgM and IgG antibodies were detected in the sera of the infected animals. Gross lesions consisted of pneumonic consolidations of the antero-ventral lobes of the lungs. Microscopically, histology showed formation of pyogranulommas in the lungs. Fungal elements typical of A. corymbifera were demonstrated in the tissues upto 15 days after infection by special stains and confirmed by indirect immunoperoxidase. Re-isolation of the fungus from lungs was also achieved consistently up to 15 days only. It was concluded that intra-nasal instillation of A. corymbifera in rabbits produced significant clinico-pathological alterations with the lesions confined mainly to the lungs. In the present study, neither systemic dissemination of the disease occurred nor were kidneys site of predilection as reported earlier. This revised version was published online in August 2006 with corrections to the Cover Date.     

Repeated surgical embryo recovery and embryo production in rabbits

The purpose of this study was to assess the embryo production after repeated surgical recovery of embryos in Gigante de Espa?a does. A total of 195 ovulatory treatments and embryo recoveries were performed from 1995 to 1999. Ovulation was induced by an intramuscular injection of 20 microg GnRH immediately after mating. Each doe was induced to ovulate up to four consecutive times at intervals of at least 50 days. Embryos were surgically collected from oviducts 68-69 h post-coitus. An average of 8.6 corpora lutea and 6.4 recovered embryos (90% of them classified as viable) were recorded from the 195 treatments. The process seemed to be less efficient in the fourth treatment, with a drop of more than two recovered and viable morulae with reference to the third (P<0.05 for both parameters) or the second recovery (P<0.1 and P<0.05, respectively). More than 20 recovered embryos and 18 viable embryos per donor doe were recorded considering the three first ovulatory treatments performed in 33% of the does (30/90). Results indicate that the methodology used in the present study could be an efficient way to maximize in vivo embryo production from rabbits.     

A novel anaesthetic regimen for surgical procedures in guineapigs.

A combination of tiletamine/zolazepam, xylazine and butorphanol provides deep surgical, long-duration anaesthesia in guineapigs with a smooth induction and recovery period. The described dosages mainly affect the respiratory functions and blood gas parameters, with a minor-to-moderate effect on the cardiovascular system.