Mouse Behavior in the Open-field Test after Meloxicam Administration.

Several analgesics are suggested for pain management in mice. Nonsteroidal antiinflammatories (NSAIDs), such as meloxicam can be administered for the treatment of inflammation and acute pain; however, several side effects can occur which include gastrointestinal ulceration and renal and hepatic toxicity. We previously performed a pilot study to test the antinociceptive activity of meloxicam in mice, but we observed behavioral changes in unoperated control mice. These observations spurred further investigation. One hypothesis for the result was potential differences in formulation between commercial brands of meloxicam. Thus, this current study aimed to evaluate the effects of 3 different commercial brands of meloxicam (20 mg/kg) in the general activity of mice using the open field test. Our results showed that meloxicam had several effects on mouse behavior and caused the formation of skin lesions at the injection site, depending on the brand of the drug. The most significant adverse effect observed was decreased exploratory activity. Grooming frequency was reduced in all groups. These adverse effects might be related to the quality of the drugs because meloxicam formulations can contain crystal polymorphisms that affect drug quality and efficacy. This study points out the importance of drug quality variation that can affect the outcome of behavioral studies in mice.

Effects of Three Consecutive Days of Morphine or Methadone Administration on Analgesia and Open-Field Activity in Mice with Ehrlich Carcinoma.

This study assessed the exploratory behavioral responses in BALB/c mice inoculated with Ehrlich ascitic carcinoma after 3 consecutive days of treatment with morphine or methadone. Fifty-three female mice, 60 ± 10 d old, were used. Seven days after intraperitoneal tumor inoculation (2 × 106 cells), the animals were randomized into 7 groups: morphine 5 mg/kg (MO5), morphine 7.5 mg/kg (MO7.5), morphine 10 mg/kg (MO10), methadone 2.85 mg/kg (ME2.85), methadone 4.3 mg/kg (ME4.3), methadone 5.7 mg/kg (ME5.7), and 0.9% NaCl (Saline) (n = 7). Drug treatments were administered subcutaneously every 6 h for 3 d. The animals were evaluated for analgesia using the mouse grimace scale (MGS) and for general activity using the open field test. The MGS was performed before tumor inoculation (day 0), on day 7 at 40, 90, 150, 240, and 360 min after drug injection, and on days 8 and 9 at 40, 150, 240, and 360 min after drug injection. The open field test was performed before tumor inoculation (day 0), on day 7 after inoculation at 40, 90, 150, 240, and 360 min after drug injection, and on days 8 and 9 after inoculation at 40, 150, and 360 min after drug injection. MGS results indicated that administration of morphine promoted analgesia for up to 240 min. Conversely, methadone reduced MGS scores only at 40 min. All tested doses promoted a significant dose-dependent increase in the total distance traveled and the average speed, and increase that was markedly pronounced on days 8 and 9 as compared with day 7. The frequencies of rearing and self-grooming decreased significantly after morphine or methadone administration. Despite the difference in analgesia, both drugs increased locomotion and reduced the frequency of rearing and self-grooming as compared with the untreated control animals.

Molecular characterization of Brazilian equid herpesvirus type 1 strains based on neuropathogenicity markers

Partial nucleotide sequences of ORF72 (glycoprotein D, gD), ORF64 (infected cell protein 4, ICP4) and ORF30 (DNA polymerase) genes were compared with corresponding sequences of EHV-1 reference strains to characterize the molecular variability of Brazilian strains. Virus isolation assays were applied to 74 samples including visceral tissue, total blood, cerebrospinal fluid (CSF) and nasal swabs of specimens from a total of 64 animals. Only one CSF sample (Iso07/05 strain) was positive by virus isolation in cell culture. EHV-1 Iso07/05 neurologic strain and two abortion visceral tissues samples (Iso11/06 and Iso33/06) were PCR-positive for ORF33 (glycoprotein B, gB) gene of EHV-1. A sequence analysis of the ORF72, ORF64 and ORF30 genes from three EHV-1 archival strains (A3/97, A4/72, A9/92) and three clinical samples (Iso07/05, Iso11/06 and Iso33/06) suggested that among Brazilian EHV-1 strains, the amplified region of the gD gene sequence is highly conserved. Additionally, the analysis of ICP4 gene showed high nucleotide and amino acid identities when compared with genotype P strains, suggesting that the EHV-1 Brazilian strains belonged to the same group. All the EHV-1 Brazilian strains were classified as non-neuropathogenic variants (N752) based on the ORF30 analysis. These findings indicate a high conservation of the gD-, ICP4- and ORF30-encoding sequences. Different pathotypes of the EHV-1 strain might share identical genes with no specific markers, and tissue tropism is not completely dependent on the gD envelope, immediate-early ICP4 and DNA polymerase proteins.