BACKGROUND: An optimal fixative, which can avoid retinal detachment, has been the subject of intensive experiments and clinical pathological studies.
OBJECTIVE: To compare the fixation effects of four different complex fixatives on mouse retina.
METHODS: Forty Kunming mice were sacrificed, and the eyeballs were enucleated and divided randomly into four groups, with 20 eyeballs in each group. The eyeballs in each group were respectively fixed in Fixative 1 (4 g paraformaldehyde were added into 0.1 mol/L phosphate buffer 80 mL, heated to 60 ℃, agitated still the powder were dissolved, then clarified with 1 mol/L NaOH. When it was cooled down, 5 mL glacial acetic acid and 10 mL acetone were added, and 0.1 mol/L phosphate buffer was added to make up the volume to 100 mL), Fixative 2 (5% potassium dichromate solution 40 mL, 4% formaldehyde 10 mL, glacial acetic acid 10 mL, trichloroacetic acid solution 10 mL, 10% sodium acetate trihydrate solution 10 mL), Fixative 3 (glacial acetic acid 10 mL, 40% formaldehyde 20 mL, physiological saline 70 mL, 75% alcohol 10 mL), and Fixative 4 (alcohol 60 mL, 40% formaldehyde 10 mL, glacial acetic acid 10 mL, chloroform 20 mL). After 24 hours of fixation, paraffin section and hematoxylin-eosin staining were performed.
RESULTS AND CONCLUSION: The retina fixed by Fixative 4 (alcohol 60 mL, 40% formaldehyde 10 mL, glacial acetic acid 10 mL, chloroform 20 mL) gave us a clear view of every layer of the retina, and retinal detachment was rarely seen. Fixative 4 promotes the permeation into the eyeballs, reduces the incidence of retinal detachment, and is better than the other fixatives.