Static magnetic field effects on impaired peripheral vasomotion in conscious rats

Abstract

We investigated the SMF effects on hemodynamics in the caudal artery-ligated rat as an in vivo ischemia model using noninvasive near-infrared spectroscopy (NIRS) combined with power spectral analysis by fast Fourier transform. Male Wistar rats in the growth stage (10 weeks old) were randomly assigned into four groups: (i) intact and nonoperated cage control (n = 20); (ii) ligated alone (n = 20); (iii) ligated and implanted with a nonmagnetized rod (sham magnet; n = 22); and (vi) ligated and implanted with a magnetized rod (n = 22). After caudal artery ligation, a magnetized or unmagnetized rod (maximum magnetic flux density of 160 mT) was implanted transcortically into the middle diaphysis of the fifth caudal vertebra. During the experimental period of 7 weeks, NIRS measurements were performed in 3- , 5- , and 7-week sessions and the vasomotion amplitude and frequency were analyzed by fast Fourier transform. Exposure for 3-7 weeks to the SMF significantly contracted the increased vasomotion amplitude in the ischemic area. These results suggest that SMF may have a regulatory effect on rhythmic vasomotion in the ischemic area by smoothing the vasomotion amplitude in the early stage of the wound healing process.

Figure 1

(a) Spatial distribution of the magnetic flux density values. (b) Spatial distribution of the magnetic gradient values.

Figure 2

The caudal artery was ligated with a suture and amputated at the fifth caudal vertebra. Caudal circulation just after the ligation was mainly supported by collateral vessels. The rod was vertically implanted into the fifth caudal vertebra.

Figure 3

Relationship between vasomotion amplitude and frequency of the mean Total Hb level change in a 3-week exposure period. C, n = 20; L, n = 20; L + S, n = 22; L + M, n = 22. PU: perfusion unit.

Figure 4

Fluctuation of Total Hb level at the frequency of 0.05 Hz 3 weeks after ligated and implanted operation. C, n = 20; L, n = 20; L + S, n = 22; L + M, n = 22. Mean ± S.D. PU: perfusion unit; *P < 0.05.