Antiallergic activity by mast cell stabilization assay
Requirements
Animals – guinea pigs = 400 – 600 gms Albino rats – 175 – 200 gms
Drugs – histamine dihydrochloride aerosol (0.2% W/V) Chlorpheniramine maleate (2mg / kg)
Disodium chromoglycoate (50mg / kg) Reagents – Saline solution (0.9%)
Egg albumin (100 µg / ml) Toludine blue solution (1%)
Instruments – microscope with 10x magnification lens
Procedure
Evaluation of bronchoconstriction in guinea pigs by using histamine aerosol-
To take two groups of guinea pigs.
Each group contains 3 animals.
Animals have to have fasted overnight.
Normal saline gives to the group-I animals’ Chlorpheniramine maleate (2mg/kg) gives to the group-II animals.
Before the drug administration animals should be exposed to the histamine aerosol (0.2%) in the histamine chamber. Then determine the endpoint.
The pre-convulsion dyspnea (PGD) is the time of exposure of histamine aerosol to the onset of dyspnea that leads to convulsion. As early air & time of onset of PCG is to be noted on day zero.
Then animals have to treat with drugs after 24 hrs. After 1 hr of drug admonition once again are exposed to histamine aerosol & PCD is determined.
The percentage (%) of protection offered by the drug can be calculated by the below formula.
Formula:
Percentage protection – (1-T1/T1)x100
Where T1=mean value of PCD before drug administration and T2=mean value of PCD after drug administration.
Observations:
| Group | Percentage protection |
| Group – 2 Chlorphemniramine maleate (2mg/kg) |
Mast cell stabilization activity:
Albino rats are divided into 2 groups.
Each containing 3 animals.
Group-1 receives normal saline. Disodium chromoglycalate (50mg/kg) gives group-2 for 3 days. Inject 10ml/kg of 0.9% saline into the peritoneal cavity on 4th day to each animal.
Massage the peritoneal region of the animal gently for 5min, then collect the peritoneal fluid and transfer it to the test tube which is carrying 7-10ml of PRMI buffer.
Centrifuge the fluid for 400-500RPM.
Discard the supernatant & wash the pellets of mast cells twice with the same buffer by centrifugation.
Add egg albumin to the above cell suspension & incubate at 370C for 10 min.
Later the suspension has to stain with 1% toluidine blue solution & observe a slide under a microscope for calculating the number of granulated and degranulated mast cells in each group
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