Objective: Evaluation of gait impairment as a measure of motor dysfunction after experimental permanent stroke, and assessment of progesterone's neuroprotective effects on functional recovery
Materials & Equipment Checklist
8 items2 from ConductScience
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Protocol Steps
View Abstract
Currently, the only approved treatment for ischaemic stroke is tissue plasminogen activator, a clot-buster. This treatment can have dangerous consequences if not given within the first 4 h after stroke. Our group and others have shown progesterone to be beneficial in preclinical studies of stroke, but a progesterone dose-response and time-window study is lacking. We tested male Sprague-Dawley rats (12 months old) with permanent middle cerebral artery occlusion or sham operations on multiple measures of sensory, motor and cognitive performance. For the dose-response study, animals received intraperitoneal injections of progesterone (8, 16 or 32 mg/kg) at 1 h post-occlusion, and subcutaneous injections at 6 h and then once every 24 h for 7 days. For the time-window study, the optimal dose of progesterone was given starting at 3, 6 or 24 h post-stroke. Behavioural recovery was evaluated at repeated intervals. Rats were killed at 22 days post-stroke and brains extracted for evaluation of infarct volume. Both 8 and 16 mg/kg doses of progesterone produced attenuation of infarct volume compared with the placebo, and improved functional outcomes up to 3 weeks after stroke on locomotor activity, grip strength, sensory neglect, gait impairment, motor coordination and spatial navigation tests. In the time-window study, the progesterone group exhibited substantial neuroprotection as late as 6 h after stroke onset. Compared with placebo, progesterone showed a significant reduction in infarct size with 3- and 6-h delays. Moderate doses (8 and 16 mg/kg) of progesterone reduced infarct size and improved functional deficits in our clinically relevant model of stroke. The 8 mg/kg dose was optimal in improving motor, sensory and memory function, and this effect was observed over a large therapeutic time window. Progesterone shows promise as a potential therapeutic agent and should be examined for safety and efficacy in a clinical trial for ischaemic stroke.
1
Surgical procedure - Middle cerebral artery occlusion or sham operation
Male Sprague-Dawley rats (12 months old) underwent either permanent middle cerebral artery occlusion or sham operations
Note: This creates the stroke model for testing
View evidence from paper
“We tested male Sprague-Dawley rats (12 months old) with permanent middle cerebral artery occlusion or sham operations”
2
Dose-response study - Initial progesterone administration
Animals received intraperitoneal injections of progesterone at 1 hour post-occlusion
1 hour post-occlusion
Note: Three dose levels tested: 8, 16, or 32 mg/kg
View evidence from paper
“animals received intraperitoneal injections of progesterone (8, 16 or 32 mg/kg) at 1 h post-occlusion”
3
Dose-response study - Subcutaneous injections at 6 hours
Subcutaneous injections of progesterone administered at 6 hours post-occlusion
6 hours post-occlusion
Note: Same dose levels as initial injection
View evidence from paper
“subcutaneous injections at 6 h and then once every 24 h for 7 days”
4
Dose-response study - Repeated daily injections
Subcutaneous injections administered once every 24 hours for 7 days following the 6-hour injection
7 days, once every 24 hours
Note: Maintains progesterone dosing throughout recovery period
View evidence from paper
“subcutaneous injections at 6 h and then once every 24 h for 7 days”
5
Time-window study - Progesterone administration at 3, 6, or 24 hours
For the time-window study, the optimal dose of progesterone was given starting at 3, 6 or 24 hours post-stroke
Starting at 3, 6, or 24 hours post-stroke
Note: Tests the therapeutic window for progesterone administration
View evidence from paper
“For the time-window study, the optimal dose of progesterone was given starting at 3, 6 or 24 h post-stroke”
6
Behavioral testing - Gait impairment assessment
Gait impairment testing performed as part of motor dysfunction evaluation
“improved functional outcomes up to 3 weeks after stroke on locomotor activity, grip strength, sensory neglect, gait impairment, motor coordination and spatial navigation tests”
8
Brain extraction and infarct volume evaluation
Rats were killed at 22 days post-stroke and brains extracted for evaluation of infarct volume
22 days post-stroke
Note: Terminal procedure for histological assessment
View evidence from paper
“Rats were killed at 22 days post-stroke and brains extracted for evaluation of infarct volume”
Subjects / Specimens
Species
rat
Strain
Sprague-Dawley
Age
12 months old
Sex
male
Underwent permanent middle cerebral artery occlusion or sham operations
