A study of the effects of pinealectomy on intestinal cell proliferation in infant newborn rats.
OBJECTIVE
Study the proliferation rate of jejunum and large intestine crypt epithelial cells, in rats pinealectomized immediately after birth.


METHODS
Twenty-four male Wistar rats were distributed into two groups: Acute group (n=12) and Chronic group (n=12). Six animals of each group were operated for removal of the pineal gland (pinealectomy-PnX), and other six were controls (sham pinealectomy-C). Animals from acute and chronic group were sacrificed 15 and 90 days after the surgery, respectively.


RESULTS
In acute group, pinealectomy of new-born rats has not caused significant alteration in cell proliferation (PnX=58.77+/-1.77 and C=60.88+/-1.10 in the descending colon/PnX=31.56+/-0.45 and C=31.73+/-0.47 in the proximal jejunum) and in crypt cell population (PnX=24.92+/-4.82 and C=23.60+/-2.48 in the descending colon/PnX=39.92+/-3.49 and C=44.32+/-5.56 in the proximal jejunum). However, in chronic group there was an uprising crypt cell production per crypt in the proximal jejunum (PnX=57.54+/-2.19 and C=47.19+/-7.3)and in the descending colon (PnX=37.78+/-2.22 and C=17.92+/-2.28).


CONCLUSIONS
As the increase of intestinal crypts epithelial cells in chronic group is a carcinogenesis predetermining factor, the understanding of the interaction between pineal gland and this event has great importance.
University Hospital, FMRP, USP, São Paulo, Brazil.
Marcelo Belini
MB
Dalio
Luis Fernando
LF
Haikel Júnior
Renato Belini
RB
Dalio
André Pera Marques
AP
Pinto
Júlio César Fernandes da
JC
Silva
Marcelo Vinícius Oliveira
MV
Vespúcio
Marco Aurélio
MA
Guimarães
Sérgio Britto
SB
Garcia
D000208:Acute Disease; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D049109:Cell Proliferation; D002908:Chronic Disease; D003106:Colon / Q000166:cytology* / Q000187:drug effects; D004195:Disease Models, Animal; D007583:Jejunum / Q000166:cytology* / Q000187:drug effects; D008297:Male; D008550:Melatonin / Q000096:biosynthesis / Q000097:blood; D008940:Mitotic Index; D010870:Pineal Gland / Q000502:physiology / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D014750:Vincristine / Q000494:pharmacology
D000972:Antineoplastic Agents, Phytogenic; D014750:Vincristine; D008550:Melatonin