Melatonin decreases apoptosis and expression of apoptosis-associated proteins in acute puromycin aminonucleoside nephrosis.
BACKGROUND
The anti-apoptotic properties of melatonin have been demonstrated previously in several in vivo and in vitro studies. Previous reports have shown increased apoptosis during puromycin aminonucleoside nephrosis (PAN). The aim of this study was to determine if melatonin (MEL) can prevent apoptosis and modify oxidative stress, an apoptosis inducer, in this experimental model.


METHODS
Rats were injected intraperitoneally with puromycin aminonucleoside. In addition, by the intragastric route they received 1 mg/kg/day of MEL or vehicle 3 days before puromycin injection and throughout the experiment. Animals were sacrificed at weeks 1 and 2 of nephrosis and frozen renal sections were studied for apoptosis by TUNEL, for apoptosis-associated proteins by monoclonal and polyclonal antibodies, and for superoxide anion (O(2)(-)) by a histochemical method. Nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH), and the activities of superoxide dismutase (SOD) and catalase were measured in homogenized kidney tissue by appropriate biochemical and enzymatic methods.


RESULTS
Increases in apoptosis, p53, Fas and Fas-ligand were observed in nephrotic animals. MEL treatment decreased apoptosis at weeks 1 and 2 in the glomerular, interstitial and tubular compartments. This was accompanied by decreased expression of p53 (glomerulus, week 1; tubules, weeks 1 and 2), Fas (glomerulus and interstitium, week 2; tubules, weeks 1 and 2) and Fas-ligand (interstitum and tubules, week 2). Increased expression of Bcl-2-positive cells was observed at week 2 in all renal compartments in MEL-treated animals. High levels of O(2)(-) and NO generation and lipid peroxidation (MDA) were found in nephrotic animals. SOD and GSH remained unchanged, and only decreased catalase activity (week 1) was observed in PAN animals. Tendencies toward decreased values of O(2)(-) and MDA content along with recovery of catalase activity (week 1) were observed in MEL-treated nephrotic animals, but were insignificant in magnitude. MEL, however, did significantly downregulate pro-apoptotic genes and upregulated anti-apoptotic genes.


CONCLUSIONS
The data demonstrate that, in PAN, melatonin has anti-apoptotic effects, which might in part be independent of the modulation of the oxidative status.
Catedra de Inmunologia, Escuela de Bioanalisis, Universidad del Zulia, Maracaibo, Venezuela
Adriana
A
Pedreañez
Jaimar
J
Rincón
Maritza
M
Romero
Ninoska
N
Viera
Jesús
J
Mosquera
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D020287:In Situ Nick-End Labeling; D007674:Kidney Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D011692:Puromycin Aminonucleoside / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
D011692:Puromycin Aminonucleoside; D008550:Melatonin