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Rat Methods

Processing of Pancreata 

Pancreata are embedded in paraffin, sectioned, and stained with H&E.

Evaluation of Pancreata 

The following parameters are evaluated:

Acinar Cell Degeneration Count and Score

Acinar cells with degeneration are counted in five 630 fields using an area on the micrometer that is 10X100 units (each unit is 1.59 µm, so 15.9 X 159 µm=2528.1 µm2, and a mean value across all five fields is calculated for each animal. A score is assigned based on the mean count as follows:

  • 0= no degeneration
  • 5= 1-4 cells
  • 1= 5-9 cells
  • 2= 10-12 cells
  • 3= 13-15 cells
  • 4= 16-20 cells
  • 5= >20 cells

Edema Score

  • 0 = none
  • 5 = one to several small foci in adipose tissue around pancreas
  • 1 = one to several large foci in adipose tissue around pancreas
  • 2 = multifocal mild affecting 10-25% of the lobules
  • 3 = multifocal moderate affecting 26-50% of the lobules
  • 4 = diffuse marked affecting 51-75% of the lobules
  • 5 = diffuse severe affecting greater than 75% of the lobules

Inflammation Score

Inflammatory cells are counted in five 630 fields using an area on the micrometer that is 10X50 units (each unit is 1.59 µm, so 15.9 X 79.5 µm=1264 µm2, and a mean value across all five fields is calculated for each animal. A score is assigned based on the mean count as follows:

  • 0= none
  • 5= focal or few sites, 1-2 inflammatory cells in adipose tissue only
  • 1= 3-4 inflammatory cells in adipose tissue only, multifocal minimal
  • 2= 5-6 inflammatory cells in adipose tissue only, multifocal mild
  • 3= 7-8 inflammatory cells, multifocal moderate affecting 26-50% of the lobules
  • 4= 9-10 inflamatory cells diffuse marked affecting 51-75% of the lobules
  • 5= greater than 10 inflammatory cells, diffuse severe affecting greater than 75% of the lobules

Summed Score

The AC degeneration score, and inflammation & edema scores are summed to determine the overall disease severity for the animal. This has a maximum value of 15.

 

Mouse Methods

 Processing of Tissue 

Pancreata are embedded in paraffin, sectioned, and stained with H&E.

Evaluation of Joints 

The following parameters are evaluated:

Acinar Cell Degeneration Count and Score

Acinar cells with degeneration are counted in five 630x fields with the most severe necrosis (the full microscope view), and a mean value across all five fields is calculated for each animal. A score is assigned based on the mean count as follows:

  • 0 = no degeneration
  • 0.5 = 1-4 cells
  • 1 = 5-9 cells
  • 2 = 10-12 cells
  • 3 = 13-15 cells
  • 4 = 16-20 cells
  • 5 = >20 cells

Coagulation Necrosis Foci Count and Score

The number of foci with coagulation necrosis are also counted in the entire section. A single focus is defined as a 200×200 µm2 region of necrosis, and larger regions are counted as multiple foci based on their total size. A score is assigned based on the count as follows:

  • 0 = no foci
  • 0.5 = 1 focus
  • 1 = 2-3 foci
  • 2 = 4-6 foci
  • 3 = 7-10 foci
  • 4 = 11-20 foci
  • 5 = >20 foci

Inflammation and Edema Score

  • 0 = None
  • 0.5 = One to several small foci in adipose tissue around pancreas, no inflammation in lobules
  • 1 = One to several large foci in adipose tissue around pancreas, no inflammation in lobules but may be in connective tissue around ducts
  • 2 = Multifocal mild, affecting 10-25% of the lobules
  • 3 = Multifocal moderate, affecting 26-50% of the lobules
  • 4 = Diffuse marked, affecting 51-75% of the lobules
  • 5 = Diffuse severe, affecting greater than 75% of the lobules

Summed Score

The AC degeneration score, coagulation necrosis score, and inflammation & edema scores are summed to determine the overall disease severity for the animal. This has a maximum value of 15.

 

Related Pages

General Inflammation

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