Dietary wolfberry upregulates carotenoid metabolic genes and enhances mitochondrial biogenesis in the retina of db/db diabetic mice

SCOPE

Our aim was to investigate whether dietary wolfberry altered carotenoid metabolic gene expression and enhanced mitochondrial biogenesis in the retina of diabetic mice.

METHODS AND RESULTS

Six-week-old male db/db and wild-type mice were fed the control or wolfberry diets for 8 weeks. At study termination, liver and retinal tissues were collected for analysis by transmission electron microscopy, real-time PCR, immunoprecipitation, Western blot, and HPLC. Wolfberry elevated zeaxanthin and lutein levels in the liver and retinal tissues and stimulated expression of retinal scavenger receptor class B type I, glutathione S-transferase Pi 1, and β,β-carotene 9',10'-oxygenase 2, and induced activation and nuclear enrichment of retinal AMP-activated protein kinase α2 (AMPK-α2). Furthermore, wolfberry attenuated hypoxia and mitochondrial stress as demonstrated by declined expression of hypoxia-inducible factor-1-α, vascular endothelial growth factor, and heat shock protein 60. Wolfberry enhanced retinal mitochondrial biogenesis in diabetic retinas as demonstrated by reversed mitochondrial dispersion in the retinal pigment epithelium, increased mitochondrial copy number, elevated citrate synthase activity, and upregulated expression of peroxisome proliferator-activated receptor γ co-activator 1α, nuclear respiratory factor 1, and mitochondrial transcription factor A.

CONCLUSION

Consumption of dietary wolfberry could be beneficial to retinoprotection through reversal of mitochondrial function in diabetic mice.

Isolation of nitric oxide synthase in the rat uterus

Nitric oxide synthase (NOS) was isolated from the uterus of adult female rats by diethylaminoethyl (DEAE) column and further purified by 2',5'-ADP agarose. The chromatographic properties revealed two isoenzymes, NOS1 and NOS2. The molecular weights of both isoenzymes was approximately 155 Kd by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS PAGE) which was similar to NOS1 and NOS2 from rat brain. The enzymes required nicotinamide adenine dinucleotide phosphate (NADPH), Ca+2 and calmodulin as cofactors. However, in the absence of calmodulin and/or calcium NOS1 was reduced by approximately 96%, while NOS2 was reduced by approximately 70%. This maximal enzyme activity was similar for brain. These results demonstrate that two isoforms of NOS are present in the rat uterus.