In the present study the specific and nonspecific cholinesterase activities of the rabbit's retinae in the fetus, the neonatal, the light-isolated, and the reopened group, which consisted of 65 healthy young rabbits, weighing about 300 to 500 gm, 33 rabbit's fetuses, and neonatal rabbits, were histochemically ovserved by means of the cholinesterase method recommended by Gerebtzoff (1953) and the embedding and sectioning method pesented by Koelle and Friedenwald (1950). Cholinesterase activity of the retinae in the 15 days fetuses was not present but began to develop in the 20 days fetuses. In the 1 week group after suturing the eyelids, the most remarkable activity of specific and nonspecific cholinesterase was observed in the posterior polar area. The nearer to the peripheral area of the retina the weaker the enzymetic activities became. In the 2 weeks group after suturing eyelids, the enzymatic activity was reduced. In the 4, and 8weeks groups after suturing the eyelides, the enzymatic activities were remarkably reduced. In the l4 days after reopening eyelide, which group has previously been kept under the condition of light isolation for 4 weeks, enzymatic activities were fairly recovered and compared with the normal control group. Consequently it is histochemically deduced that the gradual change of specific cholinesterase activities in the rabbit's retinae was closely related to the visual function.
Animals ; Animals, Newborn/enzymology ; Cholinesterases/*metabolism ; Histocytochemistry ; *Rabbits ; Retina/embryology/*enzymology

OBJECTIVETo study the effect of cerebral mild hypothermia on cerebral mitochondrial ATPase activities in neonatal rats with hypoxic-ischemic brain damage (HIBD).

METHODSEighty-four seven-day-old Wistar rats were randomly assigned into four groups: sham-operated normothermic, sham-operated mild hypothermic, HIBD normothermic and HIBD mild hypothemic. HIBD was induced by left common carotid artery ligation, followed by 8% hypoxia exposure. At each time interval of 2, 6, and 12 hrs post-hypoxia-ischemia (HI), 7 rats were sacrificed and the brain tissues were sampled for detecting the activities of mitochondrial Na+K+ATPase and Ca2+ATPase.

RESULTSThe activities of mitochondrial Ca2+ATPase decreased significantly in the two HIBD groups compared with those of the two sham-operated groups at 2, 6, and 12 hrs post-HI. The HIBD mild hypothemic group had higher mitochondrial Ca2+ATPase activities compared with the HIBD normothermic group at 2, 6, and 12 hrs post-HI (5.25 +/- 0.61 micromol/mgPr.h vs 3.17 +/- 0.81 micromol/mgPr.h 4.59 +/- 0.81 micromol/mgPr.h vs 2.26 +/- 0.53 micromol/mgPr.h4.61 +/- 0.62 micromol/mgPr.h vs 1.31 +/- 0.78 micromol/mgPr.H, respectively) (P < 0.01). The activities of mitochondrial Na+K+ATPase decreased significantly in the two HIBD groups compared with those of the two sham-operated groups at 6 and 12 hrs post-HI. A significant difference was observed in the mitochondrial Na+K+ATPase activities between the HIBD mild hypothemic and HIBD normothermic groups at 6 and 12 hrs post-HI (5.25 +/- 0.66 micromol/mg Pr.h vs 3.76 +/- 0.78 micromol/mgPr.h, 4.74 +/- 0.80 micromol/mgPr.h vs 3.12 +/- 0.53 micromol/mgPr.h; P < 0.01).

CONCLUSIONSMild hypothermia following HIBD inhibits the decline in cerebral mitochondrial Ca2+ and Na+K+ ATPase activities in neonatal rats, thus providing protective effects against HIBD.

Animals ; Animals, Newborn ; Brain ; enzymology ; Calcium-Transporting ATPases ; metabolism ; Female ; Hypothermia, Induced ; Hypoxia-Ischemia, Brain ; enzymology ; therapy ; Male ; Mitochondria ; enzymology ; Rats ; Rats, Wistar ; Sodium-Potassium-Exchanging ATPase ; metabolism

OBJECTIVETo study the expression of MMP-8 in human and rat tooth development.

METHODSImmunohistochemistry was used to detect the localization of MMP-8 protein while in situ hybridization was used to examine the expression of MMP-8 mRNA.

RESULTSThe expression of MMP-8 protein was localized in odontoblast and dentin matrix at the later bell stage in human tooth germ. The dentin was denser close to the pulp cavity. The expression of MMP-8 mRNA was found in very few polarized odontoblast at the early bell stage and all polarized odontoblast at the later bell stage in rat tooth germ.

CONCLUSIONThe results suggested that MMP-8 involved in dentin matrix rebuilding in the process of dentin formation in human and rat dental development.

Animals ; Animals, Newborn ; Dentin ; enzymology ; Embryo, Mammalian ; In Situ Hybridization ; Matrix Metalloproteinase 8 ; biosynthesis ; genetics ; Maxilla ; enzymology ; Odontogenesis ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Tooth Germ ; embryology ; enzymology

We examined the effect of endogenous and exogenous nitric oxide (NO) on protein kinase C (PKC) activity induced by angiotensin II (Ang II) in cultured neonatal rat cardiomyocytes. The results are as follows. The activity of PKC was increased by Ang II (0.01-10 micromol/L) in a dose-dependent manner, but decreased by NO precursor L-arginine (L-Arg) (10 micromol/L-10 mmol/L) in a dose-dependent manner in cultured neonatal rat cardiomyocytes. Pretreatment with L-Arg (100 micromol/L) decreased significantly Ang II -activated PKC activity and PKC activity induced by phorbol 12-myristate 13-acetate (PMA) ( 10 micromol/L), a PKC activator. Pretreatment with N(G)-nitro-L-argingie methyl ester (L-NAME), a nitric oxide synthase (NOS) blocker, may inhibit significantly the role of L-Arg on Ang II - and PMA-activated PKC activity. The activity of PKC was also decreased by NO donor sodium nitroprusside (SNP) (10 micromol/L-1 mmol/L) in a dose-dependent manner in cultured neonatal rat cardiomyocytes. Pretreatment with SNP (10 micromol/L) decreased significantly Ang II - and PMA-activated PKC activity. These results indicate that PKC was controlled by both NO and Ang II. PKC may be a cross talk between Ang II and NO in cardiomyocytes. NO abolished the activity of PKC and impaired PKC downstream signaling transduction pathway cascades.
Angiotensin II ; physiology ; Animals ; Animals, Newborn ; Cells, Cultured ; Female ; Male ; Myocytes, Cardiac ; cytology ; enzymology ; Nitric Oxide ; physiology ; Protein Kinase C ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the possible mechanism of lipopolysaccharide (LPS)-induced cardiomyocyte hypertrophy in rats.

METHODSNeonatal rat cardiomyocytes cultured in vitro were stimulated with 100 µg/L LPS for 1, 4 or 8 h and scanned by atomic force microscopy (AFM) for measurement of the two-dimensional area, three-dimensional surface area and volume of each cell. The total proteins and Na(+)-K(+)-ATPase activity in the cardiomyocytes were determined. The same measurements were also carried out in neonatal rat cardiomyocyte cultures stimulated by 0.5 µmol/L ouabain for 8 h and the total protein levels were measured.

RESULTSFollowing a 8-hour stimulation with LPS, the two-dimensional area, three-dimensional surface area and volume of the single cardiomyocyte became enlarged and the total cellular proteins increased significantly as compared with those in the normal control cells (P < 0.05). LPS treatment for 4 and 8 h resulted in significantly decreased activity of Na(+)-K(+)-ATPase in the cardiomyocytes (P < 0.05). In the cells treated with ouabain for 8 h, the two-dimensional area, three-dimensional surface area, volume of the single cardiomyocyte and the total cellular proteins increased significantly in comparison with the normal control group (P < 0.05).

CONCLUSIONLPS can result in cardiomyocyte hypertrophy in rats possibly in relation to lowered Na(+)-K(+)-ATPase activity in the cardiomyocytes after LPS exposure.

Animals ; Animals, Newborn ; Cell Enlargement ; drug effects ; Cells, Cultured ; Hypertrophy ; chemically induced ; Lipopolysaccharides ; Myocytes, Cardiac ; enzymology ; pathology ; Rats ; Rats, Wistar ; Sodium-Potassium-Exchanging ATPase ; metabolism

OBJECTIVETo study the roles of type II 11β-hydroxysteroid dehydrogenase (11β-HSD2) and it's signaling factors in the lung tissue in pathogenesis of persistent pulmonary hypertension (PPH) in neonatal rats.

METHODSSix Sprague-Dawley rats on the 19th day of pregnancy were randomly divided into PPH and control groups (n=3 each). The PPH group was intraperitoneally injected with indomethacin (0.5 mg/kg) twice daily and exposed in 12% oxygen for three days, in order to prepare a fetal rat model of PPH. The control group was intraperitoneally injected with an equal volume of normal saline and exposed to air. Neonatal rats were born by caesarean section from both groups on the 22nd day of pregnancy. In each group, 15 neonatal rats were randomly selected and sacrificed. 11β-HSD2 expression in the lung tissue of neonatal rats were observed by Confocal laser technology, and serum cortisol levels and prostacyclin, renin, angiotensin and aldosterone in the lung tissue of both groups were measured using ELISA.

RESULTS11β-HSD2 protein was widely expressed in the lung tissue of the control and PPH groups. The levels of 11β-HSD2 and prostacyclin in the lung tissue were lower in the PPH group than in the control group, while serum cortisol levels and renin, angiotensin and aldosterone in the lung tissue were higher in the PPH group than in the control group (P<0.05).

CONCLUSIONS11β-HSD2 and it's signaling factors play roles in pathogenesis of PPH in neonatal rats.

11-beta-Hydroxysteroid Dehydrogenase Type 2 ; analysis ; physiology ; Animals ; Animals, Newborn ; Female ; Hypertension, Pulmonary ; enzymology ; etiology ; Male ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

Leptin, a cytokine predominantly secreted from fat tissue, plays an important role in regulating organism energy balance. Leptin can stimulate lipolysis, but the mechanism is unclear. In order to study the molecular mechanism of leptin stimulating lipolysis, we systemically studied the mRNA expression of key lipolytic enzymes. Morphological observation, Oil Red O staining and RT-PCR were used to identify pig primary adipocytes; commercial kits were used to measure the glycerol and FFA release; Semiquantitative RT-PCR was used to detect the mRNA expression of key lipolytic enzymes. The results showed that 100 nmol/L leptin up-regulated the mRNA expression of ATGL, TGH-2, HSL, MGL and LPL (P<0.01), but down-regulated the Perilipin mRNA expression (P<0.01). At the same time, leptin promoted the glycerol release in a dose dependent manner (P<0.01), but had no effect on the FFA release (P>0.05). These indicate that leptin may mainly stimulate lipolysis in pig primary adipocytes by up-regulating the expression of ATGL, MGL, LPL and down-regulating the expression of Perilipin. The unchanged FFA release may be resulted from Leptin promoting UCPs mRNA expression and increasing FFA expenditure.
Adipocytes ; cytology ; enzymology ; metabolism ; Animals ; Animals, Newborn ; Cells, Cultured ; Leptin ; pharmacology ; Lipase ; genetics ; metabolism ; Lipolysis ; drug effects ; Male ; Monoacylglycerol Lipases ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Swine

OBJECTIVETo investigate the protective effect of mild hypothermia on rat astrocytes with traumatic or ischemic injury.

METHODSRat astrocytes in primary culture were subjected to scratching or hypoxic injury and exposed to normothermia (37 degrees celsius;) or hypothermia (34 or 32 degrees celsius;) for 24 h. The morphology of the astrocytes was evaluated by live/dead staining, and the cell injury was measured by lactate dehydrogenase (LDH) release assay.

RESULTSAs the temperature reduced the LDH release rate from the cells in hypoxic group decreased significantly, to (11.48 - or + 1.53)% at 34 degrees celsius; and (3.79 - or + 0.45)% at 32 degrees celsius; as compared to that in normothermia [(33.02 - or + 3.58)%] in the absence of rat white blood cells (WBC) (P<0.001). LDH release rate of the hypoxic cells further decreased in the presence of rat WBC to (51.14 - or + 2.17 )% at 37 degrees celsius;, (19.53 - or + 4.37)% at 34 degrees celsius; and (16.68 - or + 1.47)% at 32 degrees celsius; (P<0.001). In the scratched cells, with or without WBC, LDH release rate showed no significant variation between the 3 temperatures (P>0.05).

CONCLUSIONMild hypothermia offers obvious protective effects on rat astrocytes against ischemic damage but not against mechanical injury.

Animals ; Animals, Newborn ; Astrocytes ; enzymology ; pathology ; Brain Injuries ; therapy ; Brain Ischemia ; therapy ; Cell Hypoxia ; Cells, Cultured ; Cold Temperature ; L-Lactate Dehydrogenase ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

Animals ; Animals, Newborn ; Bronchoalveolar Lavage Fluid ; chemistry ; cytology ; Female ; Lipopolysaccharides ; toxicity ; Lung ; drug effects ; enzymology ; pathology ; Male ; Neutrophils ; cytology ; Peroxidase ; analysis ; Rats ; Rats, Wistar

OBJECTIVETo investigate the protective effects of Huperzine A, a potent acetylcholinesterase inhibitor, against the hypoxic ischemic brain damage (HIBD) of the cognitive and morphology in the neonatal rats.

METHODSPostnatal 7 days old rats were given vehicle or Huperzine A (0.05 mg/kg or 0.1 mg/kg, i.p.) following HIBD (unilateral carotid artery ligation followed by hypoxia) or sham operation, and then tested the learning ability and memory in the Morris water maze (MWM) from 36 to 40 postnatal days. The performance in MWM (escape latency, probe time) were recorded to evaluate the learning and memory dysfunction. At the end of MWM trials, the rats were decapitated and their brains were histologically analyzed. The tissue loss in different brain regions including striatum, cortex, and hippocampus were analyzed by image analysis system. The CA(1) subfield neurons numbers were counted to evaluate the brain damage. The acetylcholinesterase histochemistry staining was used to determine the activity of acetylcholinesterase in different brain regions.

RESULTSCompared with sham-operated group, HIBD rats with the vehicle treatment displayed significant tissue losses in the hippocampus (including CA(1) neurons), cortex, and striatum, as well as severe spatial memory deficits (escape latency: 44 s vs 30 s, P < 0.05, probe time: 14 s vs 40 s, P < 0.01). Huperzine A treatment (0.1 mg/kg) resulted in significant protection against both HI-induced brain tissue losses and spatial memory impairments (mean escape latency: 34 s vs 44 s, P < 0.05, probe time: 35 s vs 14 s,P < 0.01). However, Huperzine A treatment (0.05 mg/kg) did not show any significant improvement of spatial memory impairments (mean escape latency: 45 s vs 44 s, P > 0.05, probe time: 17 s vs 14 s, P > 0.05), but moderate to severe brain tissue losses. There was a pronounced reduction of CA(1) neuron density in ipsilateral hemisphere of vehicle-treated group and 0.05 mg/kg Huperzine A group compared with contralateral hemisphere or ipsilateral hemisphere of sham-operated group and 0.1 mg/kg Huperzine A group (72 vs 232, P < 0.01, 72 vs 229, P < 0.01, respectively). There was a close linear correlation between the CA(1) neurons cell number and the mean escape latency for 5 d acquisition trials (r = 0.777, P < 0.01).

CONCLUSIONThe unilateral HI brain injury in a neonatal rat model was associated with cognitive deficits, and that Huperzine A treatment may be protective against both brain injury and spatial memory impairment. Huperzine A showed a therapeutic potential for the treatment of hypoxic-ischemic encephalopathy (HIE) caused by the perinatal asphyxia.

Acetylcholinesterase ; metabolism ; Alkaloids ; Animals ; Animals, Newborn ; Cerebral Cortex ; drug effects ; enzymology ; pathology ; Cognition Disorders ; drug therapy ; physiopathology ; Corpus Striatum ; drug effects ; enzymology ; pathology ; Female ; Hippocampus ; drug effects ; enzymology ; pathology ; Hypoxia-Ischemia, Brain ; drug therapy ; Male ; Maze Learning ; drug effects ; Neuroprotective Agents ; administration & dosage ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Sesquiterpenes ; administration & dosage ; therapeutic use ; Treatment Outcome