Objective—To compare the levels of mRNA expression
of cycooxygenase (COX)-1 and COX-2 in the digital
laminae of normal horses and horses in the developmental
stages of laminitis experimentally induced
by administration of black walnut extract (BWE).
Sample Population—Samples of mRNA extracted
from the digital laminae of 5 control horses and 5
horses at the onset of leukopenia after administration
Procedure—Specimens of laminae were collected
from anesthetized horses prior to euthanasia.
Expression of COX-1 and COX-2 mRNA in laminae of
control and affected horses was evaluated via realtime
quantitative polymerase chain reaction techniques.
Results—Expression of COX-2 mRNA was significantly
increased in the BWE-treated group, compared
with that in control horses. In contrast to COX-2 regulation,
COX-1 mRNA expression was not significantly
different between groups. Interestingly, despite
consistent clinical signs such as leukopenia in all
BWE-treated horses, distinct differences in COX-2
mRNA expression were detected among those 5
horses (compared with values for control horses, the
increase in COX-2 mRNA expression ranged from no
increase to a 30-fold increase).
Conclusions and Clinical Relevance—Results indicated
that there was a significant upregulation of COX-2 mRNA expression during the developmental stages
of laminitis, with no significant change in expression of
the COX-1 isoform. These data appear to provide support
for aggressive use of nonsteroidal anti-inflammatory
drugs in horses at risk for laminitis; further investigation
into the clinical value of selective COX-2
inhibitors for treatment of laminitis in horses appears
to be warranted. (Am J Vet Res 2004;65:1724–1729)
Objective—To compare the outcomes of doublelayer
inverting anastomosis (DIA), single-layer anastomosis
(SLA), and single-layer anastomosis combined
with a hyaluronate membrane (SLA+HA-membrane)
with respect to stomal diameter, adhesion formation,
surgery time, and anastomotic healing in horses.
Animals—18 adult horses.
Procedure—Midline celiotomy and end-to-end anastomoses
were performed. In control horses (n = 6),
DIA was performed; in treated horses, SLA was performed
(6) or SLA+HA-membrane was performed (6).
Horses were euthanatized 21 days after surgery.
Abdominal adhesions were evaluated grossly and histologically.
Stomal diameters were measured ultrasonographically
and compared with adjacent luminal
diameters. Anastomotic healing was evaluated histologically
for fibrosis and inflammation, tissue alignment,
and inversion. Surgery times were recorded for
the anastomotic procedure and compared among
Results—There were significantly more adhesions in
the SLA group, compared with the DIA and SLA+HAmembrane
groups. Reduction in stomal diameters in
the DIA group was significantly greater than the SLA
and SLA+HA-membrane groups. Surgery times for
the DIA group were significantly greater than the SLA
and SLA+HA-membrane groups. Histologic findings
of fibrosis, inflammation, and mucosal healing were
similar among groups. There was significant tissue
inversion in the DIA group, compared with the 2 treatment
groups. Tissue alignment was not different
Conclusions and Clinical Relevance—Use of a
SLA+HA-membrane was an effective small intestinal
anastomotic technique. This technique was faster to
perform and resulted in a larger stomal diameter,
compared with the DIA technique and significantly
fewer perianastomotic adhesions, compared with the
SLA technique. (Am J Vet Res 2001;62:1314–1319)