Selective alteration of bovine neutrophil responses by recombinant bovine interleukin-1 beta

Amelioration of murine dextran sulfate sodium-induced colitis by ex vivo extracellular superoxide dismutase gene transfer

BACKGROUND

Although the etiology of inflammatory bowel disease has not been fully clarified, reactive oxygen species is speculated to be involved. Extracellular superoxide dismutase (EC-SOD), an isozyme of SODs, is known to function mainly in body fluids. We investigated the efficacy of an ex vivo EC-SOD gene transfer into dextran sulfate sodium (DSS)-induced colitis mice.

MATERIALS AND METHODS

Experimental colitis was induced by providing Balb/c mice with DSS in sterile distilled water provided as desired. The syngenic fibroblasts were obtained from Balb/c mice embryos and retrovirally transduced with the hEC-SOD gene. These engineered cells were confirmed to secrete EC-SOD in culture medium by enzyme-linked immunosorbent assay and were inoculated subcutaneously in the backs of DSS-treated mice. Mucosal injury of the colon was evaluated by the disease activity index (DAI: body weight, rectal bleeding, and stool consistency), grading of histologic disease severity, and levels of cytokine (tumor necrosis factor-alpha, interleukin-1beta) production. 8-Hydroxydeoxyguanosine (8-OHdG) levels in the mucosal tissue were assessed by immunohistochemical staining. Malondialdehyde (MDA) was measured using a colorimetric assay.

RESULTS

A significant improvement was observed in DAI score and histologic severity as well as in mucosal tissue levels of inflammatory cytokines, 8-OHdG, and MDA of mice treated with the EC-SOD gene as compared with those without gene therapy, not only in a mild colitis model but also in a severe colitis model. Survival of treated mice in these models was significantly prolonged.

CONCLUSIONS

Ex vivo transfer of the EC-SOD gene was feasible for treatment of DSS-induced colitis.

A comparison of the effects of signal transduction inhibitors on oxidative burst and degranulation in IL-I beta stimulated bovine neutrophils

There is little information available on IL-1 mediated signal transduction in neutrophils from species other than humans. In this study, signal transduction pathway inhibitors were used to compare signaling pathways for the oxidative burst and degranulation in bovine neutrophils stimulated with rBoIL-1 beta. Protein kinase C inhibitors (staurosporine and chelerythine), DL-propranolol, pertussis toxin (PT), genistein and verapamil significantly inhibited rBoIL-1 beta (10 ng/ml) stimulated luminol-dependent chemiluminescence (LDCL) in a dose-dependent manner, while indomethacin and zileuton had no effect. Propranolol significantly decreased both primary and secondary granule release in response to rBoIL-1 beta. Staurosporine enhanced secondary but not primary granule release, and PT increased primary and secondary granule release. In addition, propranolol inhibited the shape change induced by rBoIL-1 beta and zymosan-activated serum, whereas PT markedly decreased the response induced by zymosan-activated serum, but not rBoIL-1 beta. These findings suggest that rBoIL-1 beta stimulation of the oxidative burst, degranulation, and shape change of bovine neutrophils are mediated through distinct signal transduction pathways.

Effects of Staphylococcus aureus mastitis after endotoxin application on milk yield and composition during subsequent lactation of guinea-pigs

The effects of Staphylococcus aureus mastitis on milk yield and composition throughout subsequent lactation in lactating guinea-pigs and the role of endotoxin pretreatment on these phenomena were investigated. Primiparous lactating guinea-pigs were intramammarily inoculated with sterile saline (group 1), S. aureus strain UC 6097 (group 2), or with S. aureus UC 6097 after endotoxin pretreatment (group 3). Clinical signs and survival rate were monitored. During the second lactation, daily milk yield was measured and milk composition was determined. In primiparous inoculated guinea-pigs, moderate (group 3)-to-severe acute mastitis (group 2) was produced. During subsequent lactation, milk yield in the control group peaked on day 5 and then decreased. Concentrations of Na+ and Cl- in milk, and concentrations of fat, gradually increased, but lactose and K+ decreased. After an early decrease, NAGase in milk increased towards the end of lactation. Except for higher NAGase concentrations in group 3, milk yield and composition during the second lactation did not differ significantly between the mastitis and the control groups. Endotoxin pretreatment only plays a role in the determination of the severity of the infection.

Bovine neutrophil chemiluminescence is preferentially stimulated by homologous IL-1, but inhibited by the human IL-1 receptor antagonist

Previous studies have indicated that certain types of bovine cells preferentially respond to bovine interleukin-1 (IL-1) compared with IL-1 from other mammalian species. In this study, we demonstrate that bovine neutrophils undergo a substantially greater luminol-dependent chemiluminescence response to bovine IL-1 beta than to human IL-1 alpha, human IL-1 beta, or murine IL-1 alpha. Likewise, approximately 1000-fold less bovine IL-1 beta than human IL-1 beta was required to prime bovine neutrophils for an enhanced luminol-dependent chemiluminescence response to opsonized zymosan particles. A recombinant human IL-1 receptor antagonist was a potent inhibitor of bovine neutrophil stimulation and priming by homologous and heterologous IL-1. These data indicate a hierarchy amongst members of the IL-1 family in terms of their relative abilities to modulate the functional activation of bovine neutrophils.

Pharmacologic considerations in the management of peripartum conditions in the cow

As is true with the use of drugs in veterinary medicine in general, there are many controversial issues in the management of peripartum conditions in the cow. For example, the use of PG versus antibacterial drugs in the management of postpartum uterine infections has advocates for the use of either approach. Intrauterine versus systemic administration of antibacterial drugs for the prophylaxis or treatment of postpartum metritis is another area of debate. Clearly, more research is needed in this area. Equally clearly, however, the research results that are available are being disregarded on a daily basis. In considering this discussion of the use of drugs in the peripartum period, one is struck by the frequency that optimum drug therapy of a condition relies on the extralabel use of nonapproved preparations. What guidelines are available to the practitioner in this regard? One example is lack of availability of appropriate dosage regimens or withdrawal times for food derived from treated animals. Unfortunately, pharmacokinetic and residue studies that would aid in establishing guidelines generally are not available and, in most instances, are not forthcoming. Extrapolation of data from other species to the ruminant or extrapolation of information from one drug to a related compound (such as prediction of residue and withdrawal data from an approved aminoglycoside, dihydrostreptomycin, to another unapproved drug, gentamicin) is fraught with difficulties. The need for research in this area is obvious, and lack of such information is one of the major dilemmas in trying to establish rational drug therapy in the food-producing animal. Recent developments in drug therapy have led to innovative approaches for the management of peripartum and other diseases in cattle. The use of PG in the treatment of reproductive disorders, so commonplace and widely accepted in contemporary veterinary practice, is a relatively recent approach that continues to be refined with the development of new, more potent, more specific PG analogs. What will be the role of ceftiofur, a potent, third-generation cephalosporin that currently is approved only for the treatment of respiratory infections in cattle, in the management of reproductive tract infections? The fluoroquinolones, which represent a novel approach to the control of infectious diseases, are being increasingly used in veterinary and human medicine, and one may predict that these powerful antimicrobial drugs will find application in bovine practice, including for the treatment of peripartum infections. Pharmacologic manipulation of immune and defense mechanisms also is an approach with some promise.(ABSTRACT TRUNCATED AT 400 WORDS)