Histology and Immunohistochemistry. For human
liver biopsies, paraffin-embedded livers were deparaffinized
and stained for RIP3 as described above, except that 3-amino-9-ethylcarbazole was used instead of
3,3’-diaminobenzidine as the horseradish peroxidase–
specific chromogen. Omitting the primary antibody
(no primary immunoglobulin G control) in this protocol
abrogated the staining, demonstrating the specificity
of the immunoreactive staining (data not shown).
Images were acquired in a blinded manner using a
20 objective. RIP3 immunostaining was then scored
by an experienced pathologist (X. Liu) taking into
consideration staining intensity and percentage of positive
cells using a scale of 0-3 (0, lack of any staining;
1, faint staining in 50% cells or coarse granular staining in >20% cells).
A subset of these subjects was analyzed via morphometric
semiquantitation analysis using Image-Pro Plus
software (n ¼ 6 for control and n ¼ 11 for ALD
cases).