Pulsating electromagnetic field induces apoptosis of rat's bowel Cajal's cells

We previously have shown that pulsating electromagnetic field (PEMF) reduce expression of interstitial cells of Cajal (ICCs) in the rat gastrointestinal tract. Aim of present study was to determine whether diminished expression of ICCs in the rat's bowel after PEMF exposure was related to apoptosis and to PEMF dose.

rats were divided into two groups (n= 32). First group (n = 16) was exposed to four rising doses of PEMF from one dose 12.5 x 10(3) A(2) x h/m(2) to four doses 50 x 10(3) A(2) x h/m(2). Second group (n = 16) served as a control. Tissue samples of the rat duodenum and colon from exposed to PEMF and control animals were fixed and paraffin embedded and cryostat frozen. The tangential paraffin bowel sections were stained with anti c-Kit antibody. C-Kit positive cells were assessed by image analysis. Apoptosis detection in rat's tissues was performed with rabbit polyclonal anti-Bax antibody.

the surface of c-Kit immunopositive cells decreased in the duodenum and colon of rats stimulated with PEMF in a dose dependent manner with increase in expression of pro-apoptotic Bax protein in c-Kit immunopositive myenteric cells. The apoptosis - inducing action of PEMF on the c-Kit immunoreactivity of Cajal's cells suggests a possible therapeutical implications in diseases associated with overactive smooth muscles dysfunction. Pulsating electromagnetic field (PEMF) induced changed immunoreactivity in rat's myenteric Cajal cells. C-Kit diminished reactivity of ICCs was proved to be caused by triggering of apoptotic pathwa in ICCs upon PEMF stimulation. PEMF generated apoptosis was dependant on applied dose of PEMF and detected by immunostaining with antibody against proapoptic protein Bax.