Reduced production of hyperalgesic substances by mononuclear cells from aged rats incubated with carrageenan: role of interleukin 2 and prostaglandins.
OBJECTIVE
To compare the production of hyperalgesic substances by cells from aged (A; 24-month) and juvenile (J; 2-month) rats.


METHODS
4 x 10(5) purified mononuclear cells from J and A were 2 h-stimulated (test) or not (control) by 250 microg lambda-carrageenan/well. Supernatants (0.1 ml) were intraplantarly (ipl) injected in rat paws and development of mechanical hyperalgesia, in grams, evaluated. Rat interleukin 2 (IL 2) and prostaglandin E2 (PGE2) were also assessed for hyperalgesia development.


RESULTS
Test supernatants from A compared with J induced significantly less hyperalgesia (-56 +/- 8.1 and -88.4 +/- 4.6 g, respectively, p < 0.05, ANOVA t test). Local injection of a specific, but not a control, antiserum against IL 2 significantly blocked both pure IL 2- and stimulated supernatants-derived hyperalgesia. In contrast to PGE-like materials, IL 2 content in supernatants was compatible with hyperalgesia development.


CONCLUSIONS
Hyperalgesia induced by test supernatants was significantly less intense when derived from aged animals. IL 2 may have accounted for such hyperalgesia.
Pereira
L S M
LS
Departamento de Farmacologia do Instituto de Ciências Biológicas da Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901, Belo Horizonte, MG Brasil.
Ferreira-Alves
D L
DL
de Resende
M A
MA
Romualdo
V A
VA
Dos Reis
W G P
WG
Lopes
M T P
MT
Santoro
M M
MM
Francischi
J N
JN
D000375:Aging / Q000502:physiology*; D000818:Animals; D002351:Carrageenan / Q000494:pharmacology*; D002469:Cell Separation; D002478:Cells, Cultured; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D006930:Hyperalgesia / Q000378:metabolism*; D007202:Indicators and Reagents; D007213:Indomethacin / Q000494:pharmacology; D007376:Interleukin-2 / Q000502:physiology*; D008055:Lipids / Q000737:chemistry; D009000:Monocytes / Q000378:metabolism*; D010147:Pain Measurement / Q000187:drug effects; D011453:Prostaglandins / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000378:metabolism
D016861:Cyclooxygenase Inhibitors; D007202:Indicators and Reagents; D007376:Interleukin-2; D008055:Lipids; D011453:Prostaglandins; D002351:Carrageenan; D007213:Indomethacin