The Effect Of Spectral Of HRV After Lesion PVN In Rat

IntroductionHeart rate varility is the time vaiance of sinus beat - to - beat in period of time. Regulation of HRV is very complex and is multi - factor measured, the sympathovagal balance is tonically and phasically midulated by the interaction of at least three major factors: central neural integration, peripheral inhibitory reflex mechanisms(with negative feedback characteristics) ,and peripheral excitatory reflex mechanisms ( with positive feedback characteristics). In study of centrum , someone consider RVLM is concerned with the HF of HRV; Margaret et al thought susceptivity of pressure susceptivity neure in NTS had changed, so conduced the NTS reset the resetting of the pressure reflex resetting point. At present consider paraventricular nucleus is one of the neural regulator of cardiac, and primary influence heart rate ,blood pressur and sympathetic nerve;so the interrelation of PVN and HRV need important study. But, paper of the regulation of PVN in HRV had not reported.Our study observed frequencies change of HRV after electricity lesion PVN, and to discover the measurement of PVN in frequencies component of HRV.Materials and Methods1. Animals and experimentAdult male Wistar rat (200g -250g) ,obtained from the Experimental Animal Center, China Medical University, were used in this study . Animal were caged individually and had free access to food and water . The ambient temperature of the animal room was (24 ± 2)℃; light and darkness were alternated ; with light 6:00 to 18:00. Before experiment each rat was placed individually ina plastic cage without restraint 1 - 2h, adapting the experiment. All experimental trials were carried out from 8:00 to 12:00.2 Surgical procedures and ECG collection1% Pentobarbital Sodium injected celiac anesthesia, a electronic Stimulated needle was inserted into one of the paraventricular nucleus as described in atlas written by Louis J. Pellegrine. Lesion PVN using DC, 1mA, 60s; according to experiment project one of the animals lesion right PVN only; one of them surgical no lesion PYN; and the other lesion whole PVN. All animals were collected ECG.3. Collection uninterrupted ECG Under conscious state and data analysisAll animals were collected uninterrupted ECG Under conscious state according to standard II join at least 5min; After surgical, 4days,7days andl4days collection ECG, time form8;00 to 12;00. ECG data connected Powerlab/4st, saved in the compute. Small - animal HRV software was analysis all ECG data.ResultsAfter lesion PVN, HR of the rats had deceased , the LFn, HFn, LF/HF, in 4days, 7days and 14days: one side lesion PVN had significant compare with control group ( p < 0. 05 ) ; two sides lesion PVN had significant compare with control group ( p < 0. 05) ; lesion one side had significant compare with two sides. After operation, in lesion one PVN group, LFn, HFn, LF/HF, in 4days had significant compare with 7days ,14days (p <0. 05) ; lesion two PVN group had same result too. But, in lesion one and two PVN group , after operation 7days had no significant compare with operation 14days (p >0. 05) ; in data , lesion one and two sides PVN group ,from after operation 4 days to 7 days ,LFn and LF/HF increased significant(P <0. 05) ;HFn decreased observably (P < 0. 05) ; after 7days,the data had no change.DiscussionPVN of the hypothalamus is an important central regulator)' site of sympa-thetic activity. Jeffrey et al had demonstrated, in the new birth sheep, renal sympathetic nerve activity (RSNA) decreased to 52 ± 12% of the fetal values compare with the PVN lesioned and sham lesion animals, The PVN may play a critical role in sympathetic.In our study , after electric lesion PVN , we found the LFn, HFn and LF/HF in 4days, 7days and 14days, one side lesion PVN had significant comparewith control group (p <0. 05) ; two sides lesion PVN had significant comparewith control group(p <0.05) ; lesion one side had significant compared with twosides PVN; in lesion one PVN group, after operation 4days LFn, HFn and LF/HF had significant compared with 7days and 14days ( p < 0. 05 ) ; lesion twoPVN group had same result too; but, in lesion one and two PVN group ,afteroperation 7days had no significant compare with operation 14days(p >0. 05) ; indata , lesion one and two sides PVN group , from after operation 4 days to 7 days,LFn and LF/HF increased significant (P <0. 05) ; HFn decreased observably(P <0. 05) ; after 7days,the data had no change. These cause may other sidePVN has regulated effect to sympathetic and low nerve center after lesion onePVN, but, after lesion all PVN, the adjustment of these more decreased. Itsshow PVN has effected in regulation of HRV.After lesion two PVN, LFn, HFn, and LF/HF value of corresponding group had no significant in 7days, 14days. This may some regulation function of ANS had destroyed after lesion PVN. After one week, the scar had come into being, the change of HRV had stabilized.Malliani though: the sympathovagal balance is tonically and phasically modulated by the interaction of at least three major factors: central neural integration , peripheral inhibitory reflex mechanisms (with negative feedback characteristics) , and peripheral excitatory reflex mechanisms (with positive feedback characteristics). In the central nervus system, it not only accept the peripheral information, but also regulated by high nervus, and connected with other nervus of the same level. The ASN had integrated the various of stimulate and regulated the activity of organic. In our experiment, we only study initial the center mechanisms of the HRV, PVN has effected in the centre regulation of the HRV in rat.