Polarization microscopy of picrosirius red stained sections: a useful method for qualitative evaluation of intestinal wall collagen.

Collagen pattern in healing anastomosis of intestinal wall was compared with its normal pattern in the submucosal layer. Polarization colours were recorded for thin (0.8 micron or less) and thick (1.6-2.4 micron) collagen fibres. The polarization colours of thick collagen fibres in the anastomotic site were more greenish-yellow and yellow than those in normal intestine which were more yellowish-orange and orange. These findings indicate that the collagen in the anastomotic site 4 days after operation is less packed than the collagen of normal rat intestine. Examination of the polarization colours of Picrosirius red-stained sections is a useful procedure to follow healing of anastomotic sites or diagnosis of collagen pathology in different pathologic conditions in the intestinal wall.