1：Experimental Design and Method Selection:

The study used phosphorescence lifetime and blood flow imaging to measure retinal arterial and venous oxygen contents and total retinal blood flow in STZ diabetic rats at 4 and 6 weeks post-injection, compared to healthy controls. Methods included optical section phosphorescence lifetime imaging for PO2 measurements and blood velocity imaging with fluorescent microspheres for flow calculations.

2：Sample Selection and Data Sources:

Male Long Evans pigmented rats were used, with diabetes induced by STZ injection. Control rats (n=10), STZ/4wk (n=10), and STZ/6wk (n=10) groups were compared. Data from control rats were from previously published studies.

3：List of Experimental Equipment and Materials:

Equipment included a small-animal ventilator (Harvard Apparatus), blood gas analyzer (Radiometer), data acquisition system (Biopac Systems), phosphorescence imaging system, slit-lamp biomicroscope with laser and camera (QImaging), and various probes like Pd-porphine and fluorescent microspheres. Materials included ketamine, xylazine, STZ, and other chemicals.

4：Experimental Procedures and Operational Workflow:

Rats were anesthetized, ventilated, and underwent femoral artery cannulation. Phosphorescence and blood flow imaging were performed after probe administration. PO2 and blood flow measurements were taken from retinal vessels, and systemic parameters were monitored.

5：Data Analysis Methods:

Data were analyzed using analysis of variance (ANOVA) with post hoc Tukey's test. Linear regression was used to assess correlations. Statistical significance was set at P < 0.05.