Surgical treatment of spontaneous endometriosis in rhesus macaques (Macaca mulatta): 11 cases (2007-2011).

OBJECTIVE To determine long-term outcome for rhesus macaques (Macaca mulatta) with endometriosis that underwent surgical treatment and identify factors potentially associated with long-term outcome. DESIGN Retrospective case series. ANIMALS 11 female rhesus macaques. PROCEDURES Medical records of female rhesus macaques in which endometriosis was diagnosed between 2007 and 2011 and that underwent abdominal exploratory surgery were reviewed. RESULTS In 5 macaques, the only clinical abnormality was a caudal abdominal mass identified during a routine physical examination, and in 6 macaques, overt clinical signs of endometriosis, including anorexia, dysmenorrhea, and lethargy during menses, were reported. Five macaques had histologically confirmed complete ovarian removal, and another 5 had incomplete ovarian removal (ovarian tissue was not examined histologically in 1 macaque). Nine animals survived at least 12 months after surgery, and 6 survived at least 60 months after surgery. Macaques that did not have overt clinical signs were significantly more likely to survive at least 60 months after surgery. However, extent of ovarian removal was not significantly associated with survival 12 or 60 months after surgery. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that, in select situations, surgery (ovariectomy or ovariohysterectomy) may be curative in macaques with endometriosis and may result in long-term survival. Further, findings suggested that monitoring until clinical signs appear before performing surgery is not warranted in adult female macaques suspected to have endometriosis that only have a caudal abdominal mass and no other overt clinical signs.

Efficacy of Tramadol as a Sole Analgesic for Postoperative Pain in Male and Female Mice.

Tramadol is a centrally acting weak µ opioid agonist that has few of the adverse side effects common to other opioids. Little work has been done to establish an effective analgesic dose of tramadol specific for surgical laparotomy and visceral manipulation in mice. We used general appearance parameters to score positive indicators of pain including posture, coat condition, activity, breathing, and interactions with other mice, activity events (that is, the number of times each mouse stretched up in a 3-min period) used as an indicator of decreased pain, von Frey fibers, and plasma levels of corticosterone to determine whether tramadol at 20, 40, or 80 mg/kg prevented postoperative pain in male and female C57BL/6 mice. A ventral midline laparotomy with typhlectomy was used as a model of postoperative pain. In male mice, none of the markers differed between groups that received tramadol (regardless of dose) and the saline-treated controls. However, general appearance scores and plasma corticosterone levels were lower in female mice that received 80 mg/kg tramadol compared with saline. In summary, for severe postoperative pain after laparotomy and aseptic typhlectomy, tramadol was ineffective in male C57BL/6 mice at all doses tested. Although 80 mg/kg ameliorated postoperative pain in female C57BL/6 mice, this dose is very close to the threshold reported to cause toxic side effects, such as tremors and seizures. Therefore, we do not recommend the use of tramadol as a sole analgesic in this mouse model of postoperative pain.

Effects of buprenorphine and estrous cycle in a murine model of cecal ligation and puncture.

The effect of opioids on the immunopathology of sepsis models in mice has been controversial. In previous work, we showed that mortality and various inflammatory parameters did not differ between female mice given saline or buprenorphine after cecal ligation and puncture. To investigate further, we hypothesized that buprenorphine would not affect outcomes of sepsis at any stage of estrous. Female mice were allocated into 4 groups (n = 20 per group) according to stage of estrous. Mice then underwent cecal ligation and puncture and received either buprenorphine or saline. In 3-wk survival studies, overall survival did not differ between buprenorphine- and saline-treated mice. When mice were stratified according to stage of estrous, survival did not vary among saline-treated groups but was lower in buprenorphine-treated mice in metestrus compared with proestrus. To investigate inflammation as a potential mechanism for survival, we measured cell counts and cytokine levels in the peripheral blood and peritoneal lavage fluid at 12 and 24 h after cecal ligation and puncture. At 24 h, buprenorphine-treated mice in proestrus had more circulating neutrophils and monocytes than did saline-treated mice in proestrus and more circulating WBC than did mice in any other stage with or without buprenorphine. Our current results suggest that the effects of buprenorphine on a 50% survival model of sepsis in BALB/c female mice are minimal overall but that the stage of estrous has various effects in this model. Investigators should consider the effects of buprenorphine and estrous cycle when using female mice in sepsis research.

Development of a murine model of blunt hepatic trauma.

Despite the prevalence of blunt hepatic trauma in humans, there are few rodent models of blunt trauma that can be used to study the associated inflammatory responses. We present a mouse model of blunt hepatic trauma that was created by using a cortical contusion device. Male mice were anesthetized with ketamine-xylazine-buprenorphine and placed in left lateral recumbency. A position of 2 mm ventral to the posterior axillary line and 5 mm caudal to the costal margin on the right side was targeted for impact. An impact velocity of 6 m/s and a piston depth of 12 mm produced a consistent pattern of hepatic injury with low mortality. All mice that recovered from anesthesia survived without complication for the length of the study. Mice were euthanized at various time points (n = 5 per group) until 7 d after injury for gross examination and collection of blood and peritoneal lavage fluids. Some mice were reanesthetized for serial monitoring of hepatic lesions via MRI. At 2 h after trauma, mice consistently displayed laceration, hematoma, and discoloration of the right lateral and caudate liver lobes, with intraabdominal hemorrhage but no other gross injuries. Blood and peritoneal lavage fluid were collected from all mice for cytokine analysis. At 2 h after trauma, there were significant increases in plasma IL10 as well as peritoneal lavage fluid IL6 and CXCL1/KC; however, these levels decreased within 24 h. At 7 d after trauma, the mice had regained body weight, and the hepatic lesions, which initially had increased in size during the first 48 h, had returned to their original size. In summary, this technique produced a reliable, low mortality, murine model that recreates features of blunt abdominal liver injury in human subjects with similar acute inflammatory response.

Lipopolysaccharide binding protein inhibitory peptide alters hepatic inflammatory response post-hemorrhagic shock.

Translocation of microorganisms and endotoxin (LPS) across the gastrointestinal mucosa may exacerbate the inflammatory response and potentiate hepatic injury associated with hemorrhagic shock. Lipopolysaccharide binding protein (LBP) augments LPS signaling through TLR4. In addition, evidence suggests that TLR4-mediated injury in liver ischemia/reperfusion occurs through the IRF-3/MyD88 independent pathway. We hypothesized that administration of LBP inhibiting peptide, LBPK95A, given at the time of resuscitation would reduce liver inflammation and injury in a murine model of hemorrhagic shock by limiting LPS-induced activation of the MyD88 independent pathway. Hemorrhagic shock was induced in male, C57BL/6 mice; a mean arterial blood pressure of 35 mmHg was maintained for 2.5 h. LBPK95A peptide or equal volume Lactated Ringer's solution was administered followed by fluid resuscitation. Mice were sacrificed at 2 and 6 h post-resuscitation. At 2 h, liver mRNA levels revealed a significant reduction in IFN-ß, a cytokine produced via the MyD88 independent pathway, with LBPK95A treatment. However, mRNA levels of TNF-α, a cytokine associated with the MyD88 dependent pathway, were unaffected by treatment. The LBP inhibitory peptide did selectively reduce activation of TLR4 signaling via the IRF-3/MyD88 independent pathway. These results suggest that LBP promotes cytokine production through the MyD88 independent pathway during hemorrhagic shock.

Effects of buprenorphine on a cecal ligation and puncture model in C57BL/6 mice.

Sepsis research relies heavily on animal models. One of the most frequently used models, cecal ligation and puncture (CLP), involves surgery, and animal use committees may require the use of analgesics after CLP. However, some analgesics are immunomodulatory and may affect research outcomes. In addition, both septic inflammation and responses to opioids may vary with the sex of the subject. Therefore, we investigated the effects of buprenorphine in inbred mice of both sexes undergoing CLP. We hypothesized that buprenorphine would not significantly change the outcome or patterns of inflammation in C57BL/6 mice after CLP. Male and female C57BL/6 mice underwent CLP surgery and were randomized into 2 groups to receive either buprenorphine or saline. Three-week survival studies were performed (n = 20 per group). Survival did not differ between groups of female mice, but male mice that received buprenorphine had decreased survival compared with that of controls. Reducing the dose of buprenorphine in male mice ameliorated the difference in survival. To examine inflammation, mice (n = 10 per group) were euthanized at 12, 24, or 48 h after CLP. Cell counts and cytokines were measured in the blood and peritoneal lavage fluid. In female and male C57BL/6 mice, buprenorphine treatment resulted in few differences in inflammatory parameters, although peripheral neutrophil counts were decreased transiently in male mice. The findings suggest that the effects of buprenorphine on sepsis models in C57BL/6 mice may be sex-specific. Consequently the use of analgesics must be assessed on a study-by-study basis, and investigators should define analgesic regimens when publishing sepsis studies.