Detection of Reg3γ by Immunohistochemistry in Cerulein-Induced Model of Acute Pancreatic Injury in Mice and Rats

OBJECTIVE: In a continuation of previous work, Reg3γ protein was further evaluated as a biomarker of pancreatic injury using immunohistochemistry in an additional species. METHODS: Mice and rats were treated with intraperitoneal cerulein injections, creating acute pancreatic injury. Mice received 2, 4, or 6 doses, and rats received 1, 2, or 3 doses of cerulein creating low, medium, and high treatment groups. Control animals were dosed with phosphate-buffered saline at corresponding volumes and intervals. Groups of 6 animals were killed 1, 3, 6, 24, and 48 hours after final treatments. Reg3γ immunohistochemical staining and image analysis were performed on pancreatic tissue obtained 6, 24, or 48 hours after control or cerulein treatment. Staining was quantified using image analysis software to calculate area of positivity as a percentage of total tissue area. RESULTS: Percent positivity of Reg3γ in both species rose by 6 hours, peaked by 24 hours across all 3 cerulein doses, and dropped significantly by 48 hours. In high-dose rats with accompanying gene expression data, Reg3γ gene expression corresponded temporally with quantitative staining data. CONCLUSIONS: Reg3γ staining quantified through image analysis showed a time- and dose-response in cerulein-treated mice and rats.