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Induction of apoptosis in rat lymphocytes by starvation
Author(s) -
Otton Rosemari,
Pires Juliana,
Curi Rui
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1463
Subject(s) - apoptosis , phosphatidylserine , medicine , dna fragmentation , cytochrome c , endocrinology , ketone bodies , caspase , biology , mitochondrion , cytosol , programmed cell death , chemistry , microbiology and biotechnology , biochemistry , phospholipid , membrane , metabolism , enzyme
The aim of this study was to investigate if 24 and 48 h fasting induces apoptosis of rat mesenteric lymph node lymphocytes similarly to what was previously observed in diabetic patients and alloxan‐induced diabetic rats. Plasma levels of glucose, free fatty acids and ketone bodies (acetoacetate and β‐hydroxybutyrate) were determined in rats fasted for 24 and 48 h. The following features of cell death were evaluated by flow cytometry: loss of membrane integrity, DNA fragmentation, phosphatidylserine exposure, and mitochondrial depolarization. Accumulation of neutral lipids was determined using Nile red. Activities of caspases‐3, ‐6 and ‐8 were evaluated by using a spectrofluorometric assays. The cytochrome c release from mitochondrial intermembrane space into cytosol was investigated by Western blot analysis. Lymphocytes obtained from 24 and 48 h fasted rats presented an increase in DNA fragmentation and phosphatidylserine externalization. These apoptotic features were more pronounced after 48 h fasting when blood glucose levels were low, and the plasma levels of free fatty acids and ketone bodies were increased. There was no loss of membrane integrity in lymphocytes even after 48 h culture. Cytochrome c release from mitochondria was significantly increased in lymphocytes from fasted rats. Activities of caspases‐3,‐6 and ‐8 were significantly increased in lymphocytes from 24h fasted rats. The cells from 48h fasted animals showed an increase of caspase‐3 activity only. In conclusion, 24 and 48 h fasting caused a significant increase in the proportion of lymphocytes in apoptosis. Financial Support: FAPESP, CNPq, CAPES.