title: Curcumin Inhibits Neuronal Loss in the Retina and Elevates Ca²⁺/Calmodulin-Dependent Protein Kinase II Activity in Diabetic Rats.
abstract: OBJECTIVE
  To determine whether curcumin offers neuroprotection to minimize the apoptosis of neural cells in the retina of diabetic rats.
  
  
  METHODS
  Streptozotocin (STZ)-induced diabetic rats and control rats were used in this study. A subgroup of STZ-induced diabetic rats were treated with curcumin for 12 weeks. Retinal histology, apoptosis of neural cells in the retina, electroretinograms, and retinal glutamate content were evaluated after 12 weeks. Retinal levels of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), phospho-CaMKII (p-CaMKII), and cleaved caspase-3 were determined by Western blot analysis.
  
  
  RESULTS
  The amplitudes a-wave, b-wave, and oscillatory potential were reduced by diabetes, but curcumin treatment suppressed this reduction of amplitudes. Curcumin also prevented cell loss from the outer nuclear, inner nuclear, and ganglion cell layers. Apoptosis of retinal neurons was detected in diabetic rats. The concentration of glutamate in the retina was higher in diabetic rats, but was significantly reduced in the curcumin-treated group. Furthermore, p-CaMKII and cleaved caspase-3 expression were upregulated in the diabetic retina, but reduced in curcumin-treated rats.
  
  
  CONCLUSIONS
  Curcumin attenuated diabetes-induced apoptosis in retinal neurons by reducing the glutamate level and downregulating CaMKII. Thus, curcumin might be used to prevent neuronal damage in the retina of patients with diabetes mellitus.
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Peipei
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Tianyan
authors.initials: T
authors.lastname: Shi
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Wensheng
authors.initials: W
authors.lastname: Lei
authors.affiliation: Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China .
authors.forename: Songping
authors.initials: S
authors.lastname: Yu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism*; D053148:Caspase 3 / Q000235:genetics; D003474:Curcumin / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000188:drug therapy*; D015536:Down-Regulation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000187:drug effects* / Q000473:pathology; D013311:Streptozocin; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D018696:Neuroprotective Agents; D013311:Streptozocin; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D053148:Caspase 3; D003474:Curcumin