The false-positive responses of analgesic drugs to the intradermal serotonin- and compound 48/80-induced scratches as an animal model of itch.

Intradermal injection of pruritogens such as serotonin, histamine and compound 48/80 into the skin and then, the evaluation of the scratching behavior is the commonly used animal model to advance pruritic research and drug development. However, predictive validity of this model is poorly documented. There is a close interaction between itch and pain sensations with regard to mediation through an anatomically and functionally identical neuronal pathway. One approach is whether the existing animal model of itch differentiates itch or pain to show efficacy of clinically effective analgesic drugs as a back translation. In this study, we explored the effects of different group of analgesic drugs on serotonin and compound 48/80-induced scratching behavior in Balb-C mice. Serotonin (25 µg) and compound 48/80 (100 µg) was injected intradermally in a volume of 50 µl into the rostral part of skin on the back of male mice and scratches were counted for a 30-min observation period. Morphine (1, 3, 10 mg/kg), tramadol (20, 40, 80 mg/kg), cannabinoid agonist CP 55,940 (0.1, 0.3, 1 mg/kg), paracetamol (100, 200, 300 mg/kg) and diclofenac (50, 100, 200 mg/kg) were given intraperitoneally 30 min prior to pruritogen injection. The analgesic drugs dose dependently blocked serotonin and compound 48/80-induced straching behavior with exerting complete inhibition at certain doses. Our data suggests that intradermal pruritogen-induced scratching models may not discriminate pain and itch sensations and give false positive results when standard analgesic drugs are used.

An in vitro and in vivo investigation of the cytotoxic effects of caffeic acid (3,4-dihydroxycinnamic acid) phenethyl ester and bortezomib in multiple myeloma cells.

BACKGROUND/AIM: In this study, the in vitro and in vivo effectiveness of caffeic acid (3,4-dihydroxycinnamic acid) phenethyl ester (CAPE) in combination with bortezomib, a proteasome inhibitor, was explored in multiple myeloma (MM) cells. MATERIALS AND METHODS: The cytotoxic effects of CAPE and bortezomib were determined by XTT cell proliferation assay. Apoptosis levels were analyzed with annexin V-fluorescein isothiocyanate, nuclear factor kappa beta (NF-κB) was analyzed with electrophoretic mobility-shift assay, and interleukin (IL)-6 levels were analyzed with enzyme-linked immunosorbent assay to evaluate CAPE's mechanism of action. To investigate the in vivo effectiveness of CAPE and bortezomib, an experimental plasmacytoma model was induced in BALB/c mice. RESULTS: Increasing concentrations of CAPE and bortezomib decreased the proliferation of ARH-77 cells in a dose-dependent manner. With doses of CAPE IC50, a significant increase in apoptosis and a significant decrease in IL-6 levels were detected. The NF-κB DNA- binding activity decreased compared to the basal ARH-77 level. The administration of CAPE alone or in combination with bortezomib increased the rate of survival compared to the control group. CONCLUSION: We think that our study, which is the first to demonstrate the in vitro and in vivo effectiveness of the.combined use of CAPE and bortezomib, will be a pioneer for future human applications of CAPE in MM.

Comparison of efficacy of bromocriptine and cabergoline to GnRH agonist in a rat endometriosis model.

OBJECTIVE: To determine the effect of dopamine agonists in a surgically induced endometriosis model on rats. STUDY DESIGN: In this prospective randomized experimental study, surgical induction of endometriosis was performed by autotransplantation technique on 52 adult female Wistar-Albino rats. Endometriosis formation was confirmed by a second-look laparotomy (n:48) 1 month later. Four study groups were randomly generated according to their treatment regimens: group 1 (leuprolide acetate, n = 12), group 2 (bromocriptine, n = 12), group 3 (cabergoline, n = 12) and group 4 (control, n = 12). Endometriotic implants were excised for histopathological examination after treatment at the setting of laparotomy. The mean surface areas and histopathological glandular tissue (GT) and stromal tissue (ST) scores of endometriotic implants were studied and compared among groups. RESULTS: After 30 days of treatment, the mean surface area of the endometriotic implants of leuprolide acetate, bromocriptine and cabergoline groups was significantly decreased. The regression of endometriotic foci size in comparison to control was highest in group 1, followed by group 2, then group 3. In the histopathological evaluation both the ST and GT scores of group 1, 2 and 3 were significantly decreased in comparison to controls without a statistically significant difference between the groups. CONCLUSION: Dopamine agonists are as effective as GnRH agonists in the regression of experimental endometriotic implants in rats. Further trials are needed to elucidate the pathways affected by dopamine agonists.

The effect of relaparotomy timing on wound healing in an animal model.

BACKGROUND: The effect of the timing of the second laparotomy on wound healing is not clear. In an experimental study in rats, we aimed to investigate the effect of timing on wound healing after reoperations on the same surgical site. MATERIAL AND METHODS: Forty-eight rats were divided into four groups. The control group (GC) didn't have another laparotomy whereas the relaparotomies on the same surgical site were performed either on the 3rd, 15th or the 30th postoperative days in the three study groups (G3, G15, G30 respectively). The midline tension pressure, collagen types I, III and, histological analysis were performed from the specimens in order to assess the wound healing and strength. RESULTS: The tensile strength was the highest in GC and decreased gradually in G3, G15 and G30, the difference between the groups did not reach statistical significance. Higher collagen levels, increased fibrosis, and large defects were observed in relaparotomy groups than CG. The musculoaponeurotic gap was shortest in GC when compared to other three relaparotomy groups (P < 0.001) and, it was the longest in G30 (P = 0.004 between G3 and G30). CONCLUSIONS: Although non-statistically significant the gradual decrease in the tensile strength and the statistically significant increase in the musculoaponeurotic gap with time point out the importance of the timing of relaparotomy in the healing process. Early relaparotomies do not disrupt the healing process as much as relaparotomy performed later.

The aromatase inhibitor letrozole reduces adhesion formation after intraperitoneal surgery in a rat uterine horn model.

OBJECTIVE: To investigate, in an experimental animal study, the effects of letrozole and tamoxifen in the reduction of adhesion formation following abdominopelvic surgery. STUDY DESIGN: Thirty female Wistar albino rats were included and divided into three groups. One group received 500 µg/d tamoxifen and a second group received 1 mg/kg/d letrozole through an enteric tube. A third group did not receive any drugs and served as the control group. On the fifth day, a laparotomy was performed and the right uterine horn was injured by monopolar cautery. The left uterine horn was incised with a scalpel and sutured. The preventive therapy protocols were continued for 7 days after surgery. On the 14th day after first surgery the animals were sacrificed, and the intraperitoneal macroscopic adhesion formation and microscopic adhesion features were evaluated. The Kruskal-Wallis test was used to compare the scores of the macroscopic adhesion scores and histologic features among the three groups, followed by a post hoc Mann-Whitney test. The total histological score was analyzed with a one-way ANOVA, followed by post hoc Bonferroni correction tests. p values ≤0.05 were considered statistically significant. The level of significance was set at p≤0.016 for the post hoc tests. RESULTS: The letrozole and tamoxifen groups had significantly lower adhesion scores for the right uterine horn than the control group (p=0.005 and p=0.013, respectively). For the left horn, however, only the letrozole group had a lower macroscopic adhesion score than the controls (p=0.011). The total histological score was significantly lower in the letrozole group than in the control group (p=0.014), but no differences were found between the tamoxifen group and the control group (p=0.954). Inflammation, fibroblastic activity, collagen formation and vascular proliferation were significantly lower in the letrozole group compared with the control group (p<0.05). The foreign body reactions were similar among the three groups (p>0.05). Tamoxifen administration did not result in any significant effects on the histological scores (p>0.05). CONCLUSION: Letrozole resulted in a significant decrease in postoperative macroscopic adhesion formation and the total histological scores, but tamoxifen did not demonstrate a similar effect on the histological scores.

Comparison of the effects of meloxicam and dexketoprofen on postoperative adhesion formation in a rat uterine horn surgical model.

STUDY OBJECTIVE: To compare the effects of 2 nonsteroidal antiinflammatory drugs of different chemical classes (meloxicam and dexketoprofen) on postoperative intraabdominal adhesion formation in a rat model. DESIGN: Experimental study (Canadian Task Force classification I). SETTING: Center for research and development. ANIMALS: Thirty female Wistar albino rats. INTERVENTIONS: The animals were randomly assigned to 1 of 3 groups (10 rats per group) and received intramuscular injections of 0.5 mg/kg dexketoprofen (group 1), 0.5 mg/kg meloxicam (group 2), or 1 mL sterile saline solution (control; group 3) daily for 2 days. Laparotomy was performed, and 1 of the uterine horns was damaged via monopolar electrocautery, whereas an incision was made in the other horn using a scalpel and was sutured to promote adhesion formation. The surgeons were blinded to the treatment method. Drug administration was continued for 5 days. The animals were euthanized at 14 days after surgery. MEASUREMENTS AND MAIN RESULTS: Intraperitoneal macroscopic and microscopic adhesions were assessed using standard adhesion scoring systems. Macroscopic adhesion scores were similar among the 3 groups in each horn (p > .50). The total histologic score was significantly lower in the meloxicam group than in the control group (8.0 vs 15.5; p = .006). Dexketoprofen did not significantly affect the total histologic score (11.0 vs 15.5; p = .09) or individual items (i.e., inflammation, fibroblastic activity, foreign body reaction, collagen formation, and vascular proliferation) compared with the control group (p > .02). Meloxicam significantly inhibited inflammation and collagen formation compared with the control group (p < .02). Meloxicam was also significantly superior to dexketoprofen in reducing inflammation (p = .006). CONCLUSION: Although meloxicam did not affect clinical adhesion formation, it significantly decreased histologic scores compared with those of the control group. Therefore, meloxicam may be suitable in reducing postoperative intraabdominal adhesion formation.

Immunosuppressive effects of multipotent mesenchymal stromal cells on graft-versus-host disease in rats following allogeneic bone marrow transplantation.

OBJECTIVE: Graft-versus-host disease (GVHD) is a major obstacle to successful allogeneic bone marrow transplantation (allo-BMT). While multipotent mesenchymal stromal cells (MSCs) demonstrate alloresponse in vitro and in vivo, they also have clinical applications toward prevention or treatment of GVHD. The aim of this study was to investigate the ability of MSCs to prevent or treat GVHD in a rat BMT model. MATERIALS AND METHODS: The GVHD model was established by transplantation of Sprague Dawley rats' bone marrow and spleen cells into lethally irradiated (950 cGy) SDxWistar rat recipients. A total of 49 rats were randomly assigned to 4 study and 3 control groups administered different GVHD prophylactic regimens including MSCs. After transplantation, clinical GVHD scores and survival status were monitored. RESULTS: All irradiated and untreated control mice with GVHD died. MSCs inhibited lethal GVHD as efficiently as the standard GVHD prophylactic regimen. The gross and histopathological findings of GVHD and the ratio of CD4/CD8 expression decreased. The subgroup given MSCs displayed higher in vivo proportions of CD25+ T cells and plasma interleukin-2 levels as compared to conventional GVHD treatment after allo-BMT. CONCLUSION: Our results suggest that clinical use of MSCs in both prophylaxis against and treatment of established GVHD is effective. This study supports the use of MSCs in the prophylaxis and treatment of GVHD after allo-BMT; however, large scale studies are needed. CONFLICT OF INTEREST: None declared.

The efficiency of proanthocyanidin in an experimental pulmonary fibrosis model: comparison with taurine.

Pulmonary fibrosis (PF) is a progressive fatal disorder. Bleomycin (BLM) is a widely used chemotherapeutic agent causing PF. Numerous agents have been investigated to prevent the progression of PF so far, but there is still a need to find more efficacious agents. Proanthocyanidin (PA) is a strong antioxidant, the main ingredient of grape seed extract. Since PA is ready for use in practice, we aimed to compare the preventive effect of PA in comparison with taurine (Tau) in BLM-induced PF. Forty Wistar male albino rats were used in the study and were divided into four groups: group 1, control; group 2, BLM-induced PF group; group 3, BLM-induced PF and treated with PA group; and group 4, BLM-induced PF and treated with Tau group. Treatments were begun 10 days before and continued 21 days after BLM injection. PA and Tau effectively inhibited inflammation, edema, severity of fibrosis, fibrosis extension, inflammatory cell accumulation, iNOS staining, and hydroxyproline level as well (p < 0.05). Total histological scores of the PA group were similar to the control group; Tau was significantly higher than the control group but lower than the BLM group (p < 0.05). We believe that PA could be a new treatment choice for PF, but further studies need to be conducted to verify the findings of the current study.

Comparison of aromatase inhibitor (letrozole) and immunomodulators (infliximab and etanercept) on the regression of endometriotic implants in a rat model.

OBJECTIVE: Novel treatment strategies are needed in the treatment of endometriosis due to limited success rates with the currently available options. As inflammatory and immunological mechanisms have been shown to be involved in the mechanism of the disease, new modalities are likely to emerge. We investigated the effects of infliximab (INF), etanercept (ETA) and letrozole on the regression of experimental endometriosis. STUDY DESIGN: In this experimental randomized trial, endometriosis was induced surgically in 44 adult female Sprague-Dawley rats. Establishment of implants was confirmed in 41 animals by a second operation on the 21st day. The rats were then randomly divided into four groups. Group I (n = 10) served as controls. Group II (n = 11) received letrozole (0.18 mg/kg, i.p.), group III (n = 10, i.p.) ETA (2.016 mg/kg, i.p.), and group IV (n = 10) INF (15.12 mg/kg, i.p.) for a second 21-day period. Endometriotic implant size along with peritoneal fluid VEGF level and immunoreactivity were determined before and after the treatment in each group. RESULTS: Endometriotic implant size reduced in all treatment groups. The effect of letrozole and ETA on implant size was similar but was significantly better than INF. Level of VEGF in peritoneal fluid did not change in any treatment group but post-treatment VEGF immunoreactivity was found significantly lower in the letrozole treated group. CONCLUSIONS: Letrozole and ETA caused a regression on the implant size in experimental endometriosis. The only group with decreased VEGF expression was letrozole.

The effect of methylprednisolone on treatment in rats with induced sepsis.

In this study, an appropriate sepsis model was created in rats. Additionally, the effects of steroid treatments on survival, in connection with antibiotic treatment, were investigated. The sepsis model performed via intraperitoneal injection of 3 ml/kg fecal suspension was determined as the most appropriate model for our study. Fifteen rats were used to investigate the effect of piperacillin-tazobactam on sepsis treatment. Forty-five randomly selected rats were used to investigate the efficacy of the antibiotic-plus-steroid combination. The rats were divided into three groups of 15 rats each. Twelve hours after the administration of fecal suspension, methylprednisolone (MP) at the dose of 0.25, 0.5, and 2 mg/kg/day was given to each group, respectively, in addition to an antibiotic administered intravenously. In order to investigate the effect of steroids alone in the treatment of sepsis, 0.5 mg/kg/day MP was given intravenously to 15 rats, 12 h after the fecal suspension was administered. It was concluded that administration of MP alone shortens survival time in rats with sepsis, whereas antibiotic therapy alone increases survival time significantly in rats with sepsis. It was seen that the antibiotic-plus-steroid treatment increases survival significantly compared to rats with no treatment (p < 0.05). In addition, steroids, when added to an antibiotic treatment in sepsis, affect survival positively when compared to the group with antibiotic therapy alone, depending on the dose given. Although, not statistically significant, high doses decrease survival (p > 0.05), and very low doses increase survival and mean survival time (p > 0.05) on the basis of clinical observation and average life time. However, low doses were found to increase survival significantly (p < 0.05). We concluded that low-dose MP, in addition to the appropriate antibiotic therapy, is the optimal in the treatment of rats with intraabdominal sepsis.

D-dimer levels in the prediction of the degree of intestinal necrosis of etrangulated hernias in rats.

PURPOSE: The aim of this study was to investigate the time-dependent relation between plasma D-dimer levels and the degree of intestinal necrosis and to compare these parameters with leukocyte counts in an experimental etrangulated hernia model in rats. RESULTS: When the duration of intestinal ischemia was prolonged, serum D-dimer levels increased relative to the control group, with the difference being statistically significant at hour 2 (P = 0.027). In contrast, leukocyte counts in the 2- and 4-h strangulation group were higher that those of the control group, but the difference was not statistically significant (P = 0.625 and P = 0.846, respectively). However, in the 6-h strangulation group the levels of leukocytes were significantly higher that those of the control group (P = 0.015). CONCLUSION: Serum D-dimer measurements may be used as a more valuable diagnostic parameter than leukocyte count in the early diagnosis of intestinal ischemia, including strangulated hernia.

[The effect of paclitaxel-eluting stents on restenosis]. / Paklitaksel salan stentlerin restenoz üzerine etkisi.

OBJECTIVE: In our study we aimed to investigate the effects of paclitaxel-eluting stent on restenosis. METHODS: Sixteen porcine were randomly assigned to two groups (n=8 per group): control group animals received conventional stent implantation and study group animals -paclitaxel-eluting stent implantation. Both groups were treated with 300 mg acetylsalicylic acid and 75 mg clopidogrel daily. The degree of neointimal proliferation and effect of drug-eluting stent on restenosis were evaluated 6 weeks after by angiography and intravascular ultrasound (IVUS). RESULTS: Angiographic in-stent restenosis was lower in paclitaxel-eluting stent group (12.50 +/- 7.07% versus 41.25 +/- 28.50%, p=0.001). The IVUS data demonstrated that paclitaxel group animals had larger minimal lumen area (8.76 +/- 1.09 mm2 versus 6.23 +/- 3.10 mm2, p=0.028), smaller mean neointimal proliferation area (1.03 +/- 0.75 mm2 versus 3.55 +/- 2.86 mm2, p=0.01) and mean percent stenosis (10.71 +/- 8.10% versus 36.85 +/- 30.93%, p=0.01). CONCLUSION: This study suggests that drug-eluting stents may also have a preventive effect for the in-stent restenosis.

The bisphosphonate zoledronic acid inhibits the development of plasmacytoma induced in BALB/c mice by intraperitoneal injection of pristane.

OBJECTIVES: Bisphosphonates (BPs) are mostly used in the palliative care of myeloma-associated osteolytic lesions. Recent studies have suggested that BPs may also exert direct antitumor effects on myeloma cells. We have investigated the effect of the potent bisphosphonate, zoledronic acid (ZOL), on the development of pristane (2,6,10,14-tetramethylpentadecane)-induced plasmacytoma (PCT) in six-week-old BALB/c mice. METHODS: Different groups of pristane-treated mice also received ZOL (100 microg/kg) commencing after the development of PCT or ZOL (20 microg/kg) from the first day. Control groups received pristane alone, ZOL alone (20 microg/kg), or phosphate-buffered saline. The study was terminated on day 300, and the remaining mice were autopsied and abdominal tissues were examined histologically for PCT. RESULTS AND CONCLUSIONS: Statistical analysis revealed a significant delay in PCT development in the group receiving pristane plus ZOL (20 microg/kg) from the first day compared to the groups receiving pristane alone and pristane combined with ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.0001 and 0.0001; respectively). Kaplan-Meier analysis revealed a significant difference in survival between the group treated with pristane alone and the groups receiving pristane plus ZOL (20 microg/kg) from the first day or ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.016 and 0.023; respectively). These results indicate a direct anti-tumor effect of ZOL in pristane-induced PCT development BALB/c mice, which may contribute to their significantly increased survival. This hypothesis should now be further investigated in clinical trials.

The magazine: a major cause of bullet fragmentation.

The fragmentation impact of high-velocity bullets penetrating the body after piercing through the magazines carried by soldiers was investigated experimentally. In this study, 16 pigs and 7.62x51-mm full metal jacket bullets were used. Pigs were assigned into two groups, and within 5 minutes of their being sacrificed with overdose anesthesia, bullets were fired into the first group on which magazines were placed and into the second group on which magazines were not placed, targeting abdominal left lower quadrant. It was found that in pigs not carrying magazines, all bullets pierced through the pig; bullets were not fragmented. However, in pigs with magazines, common fragmentation in bullets and multiple organ perforations occurred. It was concluded that magazines caused the bullets to be fragmented, increasing tissue and organ damage.