ABSTRACT
Several studies have focused on the heart rate variability (HRV) of murine species, while studies discussing HRV in murine neonates and infants remain scarce, since recording hemodynamic signals through invasive methods in small animals has been found to be quite challenging. Thus, this study aimed at describing and validating a novel method to assess HRV in newborn rats. An electrocardiogram (ECG) system was used to determine RR intervals in awake newborns and evaluate HRV in normotensive (Wistar) and hypertensive (SHR) neonate rats. After birth, ECG was recorded in the awake newborns, and they were allowed to rest on a heated surface, restricted only by the weight of the adhesive ECG electrodes. The electrodes were cut and adapted to provide more comfort to the animal, and gently placed on the newborn's skin. RR intervals were recorded over a 30-min period using an ECG system together with LabChart software (4 KHz). Three sequences of 5 min each from the ECG recording period were analyzed in time and frequency domains, using CardioSeries software. ECG data resulted in a clearly interpretable signal that was used to generate an RR interval sequence through time for the analysis of HRV. SHR neonates presented increased cardiac sympathovagal balance compared to Wistar neonates (low frequency/high frequency: 3.85±0.71 vs 0.90±0.09). In conclusion, the ECG setup here described may be used to record RR intervals to assess HRV in neonate rats, thus detecting early impairment of HRV in hypertensive newborns.
Subject(s)
Animals , Rabbits , Rats , Software , Electrocardiography , Rats, Inbred SHR , Rats, Wistar , Heart Rate , HypertensionABSTRACT
Objective To observe the effects of different levels manganese (Mn) on spatial learning and memory in neonate rats.Methods Neonate rats were distributed to control (normal saline) and MnCl210,20,30mg/kg groups randomly.Each groups included 10 litters in a cage with a dam.Neonate rats were intraperitoneal injection exposed to MnCl2 over PND 1-21.All groups were evaluated behavioral performance using open field and Morris water maze.Blood and hippocampus Mn levels were determined using ICP-MS.Results 1) For each group,blood Mn were (35.58 ± 13.77) μg/L,(80.00 ± 12.98) μg/L,(238.51 ± 31.43) μg/L,(348.47 ±34.07) μg/L and hippocampus Mn were (576.82 ± 79.78) μg/g,(798.33 ± 40.60) μg/g,(1017.23 ± 117.23)μg/g,(1278.76 ± 281.48) μg/g respectively.Blood and hippocampus Mn concentrations in Mn-exposed groups were significant increased compared to control (P ＜ 0.01),and there was a positive correlation in blood Mn and hippocampus Mn(OR =0.91,95％ CI=0.81-0.96,P＜ 0.01).2) Therewere no significant differences on travelled distance in open field among all groups,which meant that Mn exposure had no effect on their locomotion.3) In the hidden platform trials of the Morris water maze test,only on 3rd day,Mn-expose groups spent more time to find the platform compared to the control(P ＜ 0.01).The average escape latency were(21.77 ± 7.10)s,(33.78 ± 9.95)s,(37.17 ± 13.68) s,(41.92 ± 16.74) s respectively.Though the latency were increased with the Mn exposure levels increasing among the Mn-expose groups,no statistically significant differences were observed.There were no statistically effects on latency to find the platform of all groups in other training days.The result in probe trails showed that there were no statistically effects on swimming velocity,the number of crossing over the former platform and the time spent in the targeted quadrant.Conclusion Mn exposure exerts effects on the learning,but no doseeffect relationship.There are no effects on memory of neonate rats of Mn exposure.
ABSTRACT
OBJECTIVE: To investigate the effects of aldosterone (Ald) on the proliferation and collagen synthesis of cardiac fibroblasts (CFs) in neonate rats and to research its mechanism. METHODS: The neonatal rat cardiac fibroblasts were induced by anchorage velocity-dependent separation method. SD rats were divided into control group, Ald (1.0?10-7 mol?L-1) group, Ald combined with spirolactone group and Ald combined with losartan group. After 24 h of exposure, CFs proliferation was measured by MTT assay and cell cycle distribution was determined with flow cytometer (FCM). Spectrophotography was used to detect the content of hydroxyproline and immunofluorescence staining method was applied to determine the protein expression of proliferation cell nuclear antigen (PCNA) and fibronectin (FN). RESULTS: As compared with control group, in Ald group the activity of CFs was increased as well as its percentage in S stage. The content of hydroxyproline and the protein expression of PCNA and FN were also increased while the percentage of CFs in G0/G1 stage was decreased (P0.05). CONCLUSION: Ald-stimulated CFs proliferation and collagen synthesis were mediated by activation of AT1 receptors and Ald receptor,and Ald receptor plays a major role. A corresponding increase in the protein expression of PCNA and FN in CFs may be related to the proliferation effect.
ABSTRACT
OBJECTIVE:To investigate the efficacy and mechanism of ademetionine for treating hyper-unconjugated bilirubinemia in neonate rats.METHODS:The model of hyper-unconjugated bilirubinemia was established in 95 neonate SD rats by subcutaneously injection of phenylhydrazine hydrochloride,then the rats were randomly assigned to model control group(treated with normal saline),therapeutic control group(phenobarbital/nikethamide)and the therapeutic group(s-adenosyl-1-methionine)q.d for 7 days all by intraperitoneal injection.Blood samples were taken at different time for the analysis of the hepatic BUGT activity and serum bilirubin.RESULTS:In therapeutic control group compared with the model control group,the serum unconjugated bilirubin was lower,and the hepatic BUGT activity of therapeutic was higher(P