The aim of the present study was to investigate whether fasting for 24 and 48 h induces apoptosis of rat mesenteric lymph node lymphocytes similar to that observed previously in diabetic patients and alloxan-induced diabetic rats. Several features of lymphocyte death were evaluated by flow cytometry. Plasma levels of glucose, NEFAs (non-esterified fatty acids) and ketone bodies (acetoacetate and β-hydroxybutyrate) were determined in rats fasted for 24 and 48 h. Lymphocytes obtained from fasted rats had an increase in DNA fragmentation and phosphatidylserine externalization after 48 h of culture, although there was no loss of membrane integrity in lymphocytes even after 48 h of culture. Cytochrome c release from the mitochondrial intermembrane space into the cytosol was increased significantly in lymphocytes from fasted rats cultured for 24 h, whereas the levels of bcl-2 and bax proteins were not affected. Activities of caspases 3, 6, 8 and 9 were increased significantly in lymphocytes from rats fasted for 24 h, whereas only an increase in caspase 3 and 9 activities were observed in rats fasted for 48 h. In conclusion, fasting for 24 and 48 h caused a significant increase in the proportion of lymphocytes undergoing apoptosis. The occurrence of apoptosis was observed by DNA fragmentation, phosphatidylserine externalization, cytochrome c release from the mitochondria and activation of the caspase cascade. These findings support the hypothesis that conditions that raise plasma fatty acids levels (e.g. diabetes and starvation) may impair immune function by causing lymphocyte death.
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Research Article| December 01 2006
Induction of apoptosis in rat lymphocytes by starvation
*Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, Butantan 05508-900, São Paulo, SP, Brazil
†Cruzeiro do Sul University, Biological Sciences and Health Centre, Regente Feijo, 1295, Analia Franco 03342-000, São Paulo, SP, Brazil
Correspondence: Dr Rosemari Otton, at Cruzeiro do Sul University, Biological Sciences and Health Centre, Regente Feijo, 1295, Analia Franco 03342-000, São Paulo, SP, Brazil (email firstname.lastname@example.org).
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Juliana Pires, Rui Curi, Rosemari Otton; Induction of apoptosis in rat lymphocytes by starvation. Clin Sci (Lond) 1 January 2007; 112 (1): 59–67. doi: https://doi.org/10.1042/CS20060212
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