Effect Of Cervical Lymphatic Blockage On Blood Pressure In Conscious Unrestrained Rats

AIM:To investigate the effect of cervical lymphatic blockage (CLB) on blood pressure (BP) in conscious unrestrained rats and to study its primary mechanism.METHODS:Sprague—Dawley (SD) rats were adopted and randomly divided into two groups as Sham operated group and CLB group. By means of monitering hemodynamic change in conscious unrestrained rats, twenty-four-hour blood pressure (SBP, DBP and MAP), blood pressure variability (BPV), heart rate (HR) and heart rate variability (HRV) were respectively measured before sham and cervical lymphatic blockage operation as their baseline and at 1st,3rd,7th,11th,15th days after operation. Meanwhile arterial baroreflex sensitivity (BRS) was measured before and at 1st,7th,15th days after operation. In addition, we undertook a series of observation on commissural nucleus of the tractus solitarius (cNTS) in rats with CLB operation which included the expression of glutamate (Glu) and gamma-aminobutyric acid (GABA), together with macro-and micro-scopical changes were examined at the same days as above.RESULTS:Values of SBP, DBP, MAP and HR significantly decreased at 1st day after CLB operation and their lowest values appeared at 7th day. The tendency of their alternation was descending early and then ascending, whereas there were reverse alterations of BPV and HRV. BRS reduced in CLB rats with no apparent recovery from 7th day. The neurons showed a significant degeneration in cNTS, including cells shrunkening, vacuoles or cavities alternating with pyknotic, asymmetrical nuclei and clumps of heterochromatin around the edge of the nuclear membrane. Additionally, there was kyto-gathering phenomenon. The alternation above was much predominant from 5 to 7 day after CLB.CONCLUSION:CLB results in reduction of blood pressure and dysfunction of nervous regulation on cadiovascular system in conscious unrestrained rats. The alternation was mainly induced by destructive structure in cNTS after CLB.