Objective: To research the regulating effects of Xiaomengling on the tumor necrosis factor α (TNF-α), Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signaling pathway, and to study its mechanism in preventing and curing diabetic retinal microangiopathy. Methods: This was
an experimental research study. Fifty male SD rats were chosen and acclimated for 5 days. Eight rats were randomly chosen as the blank group; diabetic models were established in the other 42 rats with streptozotozin (STZ). Forty rats were modeled successfully and were divided randomly into 4 groups: 10 rats were the model group and 30 rats were the treatment group. In the treatment group, 10 rats were given a 0.1 g/100 g dose of Xiaomengling (low-dose group), 10 were given a 0.2 g/100 g dose of Xiaomengling (medium-dose group), and 10 were given a 0.3 g/100 g dose of Xiaomengling (high-dose group). After 4 months of treatment, body mass and blood sugar change were observed, and changes in the retinal ultrastructure were observed under light microscopy and electron microscopy. The protein expression change in TNF-α, JAK2/STAT5 was observed by Western blot. Relevant data were analyzed with repeated measures analysis of variance. Results: TNF-α, JAK/STAT expression was visible in the retinas of the blank group. More expression was visible in the model group; expressions were reduced successively in the low-dose, medium-dose and high-dose groups. The comparison between groups was statistically significantly (F=4.61, 4.23, 3.28, P<0.05). By observing retinal structures of rats under light microscopy, rats in the blank group had normal retinal structures. Rats in the model group had deranged distribution in each layer, obvious retinal edema and telangiectasia, decreased number of ganglion cells, karyopyknosis and inner nuclear layer vacuolar degeneration. Rats in the high-dose treatment group had default arrangements in each retinal layer, slight edema, a decreased number of ganglion cells and inner
nuclear layers. Under retinal electron microscopy, rats in the blank group had normal retinal structures. The middle parts of the retinal rod outer segments of rats in the model group were ruptured, dissolved and degenerated. The mitochondrial cristae disappeared, and had no orderly pattern, their cones were irregular
in shape, chromatin was distributed unevenly in the nucleus, the retinal capillary basement membrane was thickening and the channel was narrow. The spaces between the retinal rod outer segments in the high-dose treatment group were expanded and were not regular enough in alignment. Some of the mitochondria were swollen and deformed, the nuclear chromosomes in the cone cells had no orderly pattern, and the thickness of the retinal capillary basement membrane was uneven. Conclusions: Xiaomengling has significant regulating effects on the TNF-α and JAK2/STAT5 signal transduction pathway of diabetic rats, and can
effectively slow or prevent diabetic retinal microangiopathy.