Apoptotic Cells In Group Research Articles

Liquid nitrogen-cryopreserved tarsal plate and palpebral conjunctival transplantation for the repair of tarsal defects

The objectives of this study were to compare the efficiency of three methods for repairing tarsal defects (glycerine-preserved, alcohol-preserved and cryopreserved tarsal plate and palpebral conjunctival transplantation) based on histopathological changes and apoptosis, and to evaluate the clinical effects of repairing tarsal defects by liquid nitrogen-cryopreserved tarsal plate and palpebral conjunctival transplantation. Forty-eight rabbit eyes with tarsal defects were equally divided into three groups and transplanted with tarsal plates and palpebral conjunctivae under the following conditions: Group 1, liquid nitrogen cryopreservation; Group 2, glycerine preservation; and Group 3, alcohol preservation. Histopathological changes in the transplants were observed by light microscopy 1 week, 1 month and 3 months postoperatively. Apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Clinically, transplantations of liquid nitrogen-cryopreserved tarsal plates and palpebral conjunctivae were performed in 30 eyes (29 cases) to repair tarsal defects caused by the excision of neoplasms. The postoperative inflammatory reaction and number of apoptotic cells in Group 1 were lower compared with those in Groups 2 and 3. Clinically, of the 30 eyes operated on, 14 were cured, 15 improved and 1 failed between 6 and 90 months of follow-up. Liquid nitrogen-cryopreserved tarsal plate and palpebral conjunctival transplantation is an easy, feasible and convenient procedure. Its effects are fairly favorable, with only a small rejection rate postoperatively. Therefore, it is an ideal method for repairing tarsal defects.

Effect and mechanism of RetroNectin on the proliferation and cytotoxic activity of acute leukemia natural killer cells

To explore the effects of precoated RetroNectin on the proliferation and cytotoxicity of natural killer cells (NK) from acute leukemia (AL). Mononuclear cells (MNCs) were isolated from peripheral blood of complete remission AL patients. The MNCs were cultured in vitro precoated with 50 µg/ml RetroNectin (group I), 25 µg/ml RetroNectin (group II) and by the traditional method (control group) to generate NK. The changes of growth rate, phenotypic characterization, secretion of cytokines of NK, cell cycle, apoptosis and cytotoxicity of NK were determined. The amplification of NK in group I ((51 ± 9)×10(6)) and II ((79 ± 16) ×10(6)) were higher than that in control group ((37 ± 11)×10(6)) (both P < 0.05), and the amplification of NK in groupII was higher than that in group I (P < 0.05). There were no differences among three groups with regards to the phenotypic characterization of CD3(-)CD56(+). The secretions of interleukin 2, interleukin 12, tumor necrosis factor alpha and interferon gamma in group I and II were higher than that in control group (all P < 0.05). The expression of CD25 positive cells in groups I (38.2% ± 4.1%) and II (37.5% ± 5.1%) were higher than that in control group (24.2% ± 5.8%) (both P < 0.05). The expression of NKG2D positive cells in groups I (81.6% ± 17.9%) and II (85.7% ± 20.1%) were higher than that in control group (63.6% ± 21.9%) (both P < 0.05). The percentages of G(1) stage cells in groups I (50% ± 10%) and II (49% ± 11%) were lower than that in control group (71% ± 15%) while the percentages of S stage cells in groups I (36% ± 14%) and II (37% ± 8%) were higher than that in control group (19% ± 10%) (all P < 0.05). But no difference existed between two groups (all P > 0.05). The expression of cell cycle regulatory genes p21 and p27 were reduced in groups I and II. The percentages of apoptotic cells in groups I (10.7% ± 2.1%) and II (9.4% ± 3.1%) were lower than that in control group (29.6% ± 10.3%) (both P < 0.05). The cytotoxicity to AL cells in groups I (82% ± 21%) and II (80% ± 18%) were higher than that in control group (61% ± 14%) (both P < 0.05) at the E/T scope 20:1. But no difference existed between two groups (all P > 0.05). The proliferation and cytotoxicity of NK cells may be boosted by precoated RetroNectin.

Histopathologic and apoptotic effect of nanosilver in liver of broiler chickens

Silver nanoparticles can destroy bacteria, viruses and fungi; therefore, it is recommended as a disinfectant and can be used as a drug in the treatment of some non-curable viral disease in livestock. The aim of the present investigation was to study the effects of nanosilver induced toxicity on the liver of broiler chickens. This study was carried out on 240 one-day-old male broiler chickens (Ross 308) in acompletely randomized design (CRD) in four treatments at 0 (control), 4, 8 and 12 ppm levels of silver nanoparticles that was added daily to the drinking water with four repetitions within 16 separate cages and 15 birds in each pen. At the end of theexperiment (day 42), 32 chicks were randomly selected and slaughtered thereafter,H&E, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and light microscope was used to examine livers. Liver histopathology and H&E staining showed dose depended changes such as fatty degeneration, sinusoidal congestion, central vein dilatation, necrosis in hepatocytes and fibrosis. TUNEL staining showed significant (p<0.01) increase of apoptotic cells in groups 3 (8 ppm) and 4 (12 ppm). Data were statistically analyzed using ANOVA. Lesions and apoptotic cells in groups 3 (8 ppm) and 4 (12 ppm) were more severe than in group 2 (4 ppm). It can be concluded that higher concentrations of nanosilver (8 and 12 ppm) can induce sever lesions in chickens liver. Key words: Broiler chicks, liver, histopathology, immunohistochemistry, TUNEL.

Experimental research on the inhibition of SALL4 expression in acute myeloid leukemia THP-1 cells by RNA interference

Objective To inhibit the expression level of SALI4 in AML cell line THP-1 and investigate its potential effects on pathogenesis of leukemia. Methods AML cell line THP-1 was transfected with plasmids that expressed small interfering RNA targeting SALL4. The samples were divided into 4 groups:(1) blank group: samples with not any treatments; (2) control group: cells with empty pRS vector alone;(3) test1 group:cells with SALL4-shRNA-pRS-1 plasmid transfection complex; (4) test2 group:cells with SALL4-shRNA-pRS-2 plasmid transfection complex. The expression levels of SALL4 mRNA and protein were measured by real time fluorescence quantitative PCR and WB. C-myc, Cyclin D1 and β-catenin were important components of Wnt/β-catenin signaling pathway and their expression levels in SALL4 knockdown THP-1 cells were detected by real-time fluorescence PCR. Furthermore, THP-1 apoptosis was analyzed by flow cytometry after Annexin V-PI staining. Results Real time fluorescent quantitative PCR illustrated that the expression of SALL4 in testl group, test2 group, control group and blank group were ( 36. 0 ± 4. 3 ) %,(32. 0 ± 2. 4) %, ( 102. 0 ± 6.5 ) % and ( 100. 0 ± 2. 6 ) % respectively. There was statistical significance ( F = 226. 3, P < 0. 05 ). The expression of SALL4 in testl and test2 group respectively were significant lower than that in blank group (t = 19.7,19. 1, P<0. 05). The expression of SALL4 had no significant difference between blank group and control group (t = 1.1, P ＞0. 05). Western blot analysis revealed SALL4 protein in testl and test2 group were significantly decreased compared with those of control and blank group. All above data indicated the high efficiency of RNA interference targeting SALL4. Comparing with the blank group, the relative expression of C-myc, Cyclin D1 and β-catenin mRNA in test1, test2 and control group were(44.0 ±6.2)%,(44.0 ±5.1)% and (107.0±13.6)%;(22.0±4.5)%,(25.0±3.5)% and (48.0 ± 7. 6 ) %; ( 42.0 ± 3.5 ) %, ( 59. 0 ± 3.7 ) % and ( 79. 0 ± 5.6 ) %. The expression of C-myc,β-catenin and Cyclin D1 mRNA in testl and test2 group were significant lower than that in blank group (t = 10. 1,9. 5, 23. 3, 22. 9; 17.4, 12. 4; P < 0. 05). The percentage of apoptotic cells in group of test1,test2,control, blank were (57.2 ±9.1)%, (34.4 ±8.6)%, (14.4 ±3.6)% and (14.8 ±4.8)%respectively. There was statistical significance ( F = 42. 5, P < 0. 05 ). After the inhibition of SALL4, the percentages of apoptotic cell in testl and test2 group were significantly increased( t =9. 7, 4. 5 ;P <0. 05).Conclusion The inhibition of SALL4 in leukemia cell line THP-1 downregulates the expression of cell proliferation related genes such as C-myc, Cyclin D1,β-catenin and promoted apoptosis. Key words: Leukemia; Cell line, tumor; Transcription factors; RNA interference; Apoptosis

Influence of aoustic contrast agent with diagnostic ultrasound on rabbits' spermatogenic cell

Objective To study the impact of ultrasound contrast agent with different doses or imaging modes on rabbit spermatogenic cell in the diagnosis of radiation dose.Methods Thirty-three New Zealand white rabbits were randomly divided into 3 groups.In group Ⅰ ,three minutes gray scale ultrasound radiation was performed for three rabbits.In group Ⅱ, SonoVue was bolus injected from ear vein for eighteen rabbits.The rabbits in this group were divided into 6 sub-group according to different doses and different sampling times, the single injections of SonoVue with dosage of 0.1 ml/kg(A1, A2) or 1 ml/kg (C1 ,C2) and repeated injections with dosage of 0.1 ml/kg interval 15 min (B1 ,B2) were taken.In group Ⅲ ,twelve rabbits were bolus injected with SonoVue and then the agent bubbles were blasted when the SonoVue suffused the whole testis.The rabbits in this group were divided into 4 sub-groups according to different doses and different sampling times, and the dosages of SonoVue were 0.1 ml/kg(D1, D2) and 1 ml/kg(E1,E2).Testis were drew immediately or 24 hours later for the observation under light microscope and transmission electron microscope.Results Apoptotic cells in group Ⅲ were more than those in group Ⅰ and Ⅱ ( P ＜0.05) ,while no significant difference of the total number of apoptotic cells between group Ⅰ and Ⅱ ( P ＞0.05).The appearances of focal ultra-structural damage were observed by transmission electron microscope in group C1, such as intercellular space widening and mitochondria swelling, and no distinct damage were observed in the other groups.The appearances of intercellular space widening, mitochondria swelling and cellular edema were observed by transmission electron microscope in group Ⅲ, and spotty necrosisetc was also observed in group D1 and E1.Conclusions Large dose of contrast agent could cause germ cells slight instantaneous effects, while conventional dose had no effect.Contrast agent blasting may cause germ cells unrecoverable damage. Key words: Ultrasonography; Microbubbles; Spermatids; Apoptosis

Effect of rifampicin on the risk of steroid-induced osteonecrosis of the femoral head

To investigate the effects and possible mechanism of rifampicin on steroid-induced osteonecrosis of the femoral head (ONFH). Bone marrow stromal cells (BMSC) separated from male rats were cultured in vitro without any treatment (Group mA), exposed to dexamethasone (Group mB), treated with rifampicin (Group mC), and exposed to dexamethasone and rifampicin simultaneously (Group mD) respectively (n = 5 in each group). After 7 days, P-glycoprotein (P-gp) activity and adipogenesis of the BMSC were evaluated. In an in vivo experiment, 80 rats were randomly divided into 4 groups (n= 20 in each group). Group A received intragastric saline for 5 weeks. Group B received intragastric saline for one week, followed by subcutaneous methylprednisolone and saline for 4 weeks. Group C received intragastric rifampicin for 5 weeks. Group D received intragastric rifampicin for one week, followed by subcutaneous methylprednisolone and rifampicin for 4 weeks. At the end of the experiment, all rats underwent analysis of P-gp activity of BMSC, P-gp expression in the femoral heads, MRI and histomorphometry of the femoral heads. In vitro, the P-gp activity of BMSC increased and lipid accumulation decreased significantly in Group mD, compared to Group mB. In vivo, P-gp activity and P-gp expression in Group D increased compared to Group B. The mean area of MRI abnormal signal, adipocytic variables and apoptotic cells in Group D decreased, mean percentage of the whole epiphysis made up by the epiphyseal ossification center and trabecular structure variables improved compared to those in Group B. The incidence of ONFH was lower in Group D (50%) than in Group B (80%). Rifampicin may decrease the risk of steroid-induced ONFH by enhancing P-gp activity, thus preventing steroid-induced BMSC adipogenesis.

Chemopreventive Action of Diclofenac in Dimethybenzanthracene Induced Lung Cancer in Female Wistar Rat

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to be effective antineoplastic agents that block prostaglandin formation by inhibiting the enzyme cyclooxygenase (COX), which exists in two isoforms, COX-1 and COX-2. COX-2 is over expressed in lung cancer. The present study evaluates the chemopreventive efficiency of diclofenac, which is a preferentially selective COX-2 inhibitor in lung cancer. Female Wistar rats were divided into 4 groups. Group 1 served as control and received saline intratracheally, once. In group 2 lung cancer was induced by a single intratracheal instillation of dimethybenz(a)anthracene (DMBA) (20 mg/kg body weight). Group 3 was given the intervention of diclofenac (8 mg/kg body weight) daily by oral gavage, in addition to DMBA. Group 4 received diclofenac alone. After 18 weeks of treatment, animals were sacrificed and various studies done. COX-2 expression as seen by western immunoblot and immunohistochemistry (IHC) was increased in the DMBA group, while diclofenac intervention was able to bring down the levels of the enzyme. Apoptosis studies by DNA fragmentation, TUNEL and fluorescent dyes reveal the lowered number of apoptotic cells in group 2. The levels were restored by diclofenac treatment in group 3. There was also a significant reduction in tumor incidence in DMBA+Diclofenac treated animals. All these results indicate that diclofenac acts as an effective chemopreventive agent that mediates its effects by the induction of apoptosis in cancer tissue and suppression of COX-2 enzyme.

Microwave tissue coagulator induces renal apoptotic damage to preserved normal renal tissue following partial nephrectomy

We assessed the extent of apoptotic damage induced by the microwave tissue coagulator (MTC) in the preserved normal renal tissue following partial nephrectomy. Eleven patients who underwent nonischemic partial nephrectomy with MTC (group M) were enrolled in this study. The other 11 patients who underwent cold-ischemic partial nephrectomy without the use of MTC were enrolled as controls (group C). There were no significant differences in tumor size or age between the two groups. Renal damage was evaluated by counting apoptotic cells in the normal renal tissue surrounding the tumor tissue. Immunohistochemical staining with single-stranded DNA was carried out to investigate the apoptotic cells. The number of apoptotic cells in group M ranged from 275 to 508 per 1,000 cells, with a median value of 421. The number in group C ranged from 122 to 466 per 1,000 cells with a median value of 286. The number of apoptotic cells in group M was significantly greater than that in group C (p = 0.006). Blood loss in group C was significantly greater than that in group M (p < 0.0001). This study points out that renal damage induced by the use of MTC comprises not only necrosis but also apoptotic change. Although MTC is useful for controlling renal parenchymal bleeding during partial nephrectomy, we must consider that renal apoptotic damage caused by the MTC may spread beyond the coagulated necrosis area.

Extracorporeal shock wave treatment modulates skin fibroblast recruitment and leukocyte infiltration for enhancing extended skin‐flap survival

Extracorporeal shock wave (ESW) treatment has a positive effect of rescuing ischemic skin flaps. This study assessed whether ESW treatment rescues the compromised flap tissue by suppressing the apoptosis of ischemic tissue and recruiting tissue remodeling. We used a random-pattern extended dorsal-skin-flap (10 x 3 cm) rodent model. Thirty-six male Sprague-Dawley rats were divided into three groups. Group I, the control group, received no treatment. Group II received one session of ESW treatment (500 impulses at 0.15 mJ/mm(2)) immediately after surgery. Group III received two sessions of ESW treatment, immediately and the day after the surgery. Results indicated that the necrotic area in the flaps in group II was significantly smaller than that of the flaps in group I (p<0.01). Transferase dUTP-nick end labeling (TUNEL) analysis revealed a significant decrease in the number of apoptotic cells in group II. Hydrogen peroxide (H(2)O(2)) expression in circulation blood was significantly decreased in group II on the day after ESW treatment. Immunohistochemical staining indicated that compared with no treatment, ESW treatment could substantially increase proliferating cell nuclear antigen (PCNA), endothelial nitric oxide synthase, and prolyl 4-hydroxylase (rPH) expression, reduce CD45 expression, and suppress 8-hydroxyguanosine (8-OG) expression in the ischemic zone of the flap tissue. In conclusion, ESW treatment administered at an optimal dosage exerts a positive effect of rescuing ischemic extended skin flaps. The mechanisms of action of ESWs involve modulation of oxygen radicals, attenuation of leukocyte infiltration, decrease in tissue apoptosis, and recruitment of skin fibroblasts, which results in increased flap tissue survival.

The Role of sFas in the Immune Escape Mechanism and Progression of Cancer Larynx

This work assess serum levels of soluble Fas form (sFas) in patients with different stages of laryngeal squamous cell carcinoma(LSCC) to investigate its prognostic significance. We correlate its levels with the morphological changes of peripheral blood cells via buffy coat examinatin. The study population included 70 patients clinically diagnosed and pathohistologically confirmed LSCC in addition to 20 healthy controls. According to TNM classification 33(47.1%) patients were in stage I (group I) and 24(34.3%) in stage II (group II), 13(18.5%) in stage III (group III). The results revealed that the mean serum level of sFas (pg/ml) in the control group was 51.2, in group I was 66.33, in group II was 81.33 and in group III was 112.45. Statistical analysis of the mean of sFas by ELISA test in the patients' groups in comparison to the control revealed a significant increase of both group II and III in comparison to the control group (P &lt; 0.01) but there was no significant difference (P &gt; 0.05) between group I in comparison to either the control or group II. There was a significant difference (P &lt; 0.05) between group I in comparison to group III. LM examination revealed massive extent of the apoptotic cells in group III when compared to both group I and group II. EM examination of the buffy coat revealed apoptotic changes, mainly in the peripheral blood mononuclear cells (PBMNCs), represented by surface membrane ruffles and blebs with clumped nuclear chromatin and vacuolated cytoplasm. In conclusion, this study may help us to better understand one of the escape mechanisms in cancer larynx. This mechanism is represented by the significant increase in both the serum level of sFas and the morphological apoptotic changes that detected in PBMNCs. Soluble Fas may contribute to the progression of laryngeal cancer. It can be used as an attractive target for anticancer therapy and may be considered as a marker of disease progression and poor prognosis in laryngeal cancer.

Neuroprotective effects of Ac.YVAD.cmk on experimental spinal cord injury in rats

Background Apoptosis as a cell death mechanism is important in numerous diseases, including traumatic SCI. We evaluated the neuroprotective effects of Ac.YVAD.cmk and functional outcomes in a rat SCI model. Methods Thirty rats were randomized into 3 groups of 10: sham-operated, trauma only, and trauma plus Ac.YVAD.cmk treatment. Trauma was produced in the thoracic region by a weight-drop technique. Group 3 rats received Ac.YVAD.cmk (1 mg/kg, ip) 1 minute after trauma. The rats were killed at 24 hours and 5 days after injury. Efficacy was evaluated with light microscopy and TUNEL staining. Functional outcomes were assessed with the inclined plane technique and a modified version of the Tarlov grading system. Results At 24 hours postinjury, the respective mean number of apoptotic cells in groups 1, 2, and 3 were 0, 5.26 ± 0.19, and 0.97 ± 0.15. Microscopic examination of group 2 tissues showed widespread hemorrhage, edema, necrosis, and polymorphic nuclear leukocyte infiltration and vascular thrombi. Group 3 tissues revealed similar features, but cavitation and demyelination were less prominent than those in group 2 samples at this period. At 5 days postinjury, the respective mean inclined plane angles in groups 1, 2, and 3 were 65.5 ± 2.09, 42.00 ± 2.74, and 52.5 ± 1.77. Motor grading of animals revealed a similar trend. These differences were statistically significant ( P < .05). Conclusions Ac.YVAD.cmk inhibited posttraumatic apoptosis in a rat SCI model. This may provide the basis for development of new therapeutic strategies for the treatment of SCI.

Evaluation of Apoptosis in Peripheral Blood Lymphocytes of Renal Transplant Patients

The aim of this study was to evaluate the occurrence of apoptosis and the expression of FasL and IL-2 genes in apoptotic peripheral blood mononuclear cells (PBMC) at different posttransplant periods. Three groups of patients were studied: group 1, kidney transplant recipients at least 1 year posttransplant ( n = 17); group 2, kidney transplant recipients at least 5 years posttransplant ( n = 15); and a control group composed of 7 healthy subjects. Apoptosis was detected by annexin flow cytometry and gene expression by reverse transcription polymerase chain reactions. The percentage of apoptotic cells was significantly higher in groups 1 (42 ± 4%) and 2 (37 ± 3%) than the controls (27 ± 2%; P < .0001). Apoptotic cells in group 1 was significantly higher than in group 2 ( P < .005). A significant difference in FasL expression was observed between groups 1 and 2 ( P < .001) and the immunosuppressive regimen. These findings suggest that PBMC of kidney transplant recipients are more susceptible to activation-induced cell death and that the Fas-FasL pathway is involved in this process.

生体肝移植の問題点―特に過小グラフト対策について―

Background Recent advancement of liver transplantation technology and donor shortage has urged patients to have living donor liver transplantation. One of the issues is small-for-size graft syndrome, which is life-threatening with severe liver damage by excessively elevated portal pressure in an adult case and difficult to solve. Materials and Methods Twelve beagle dogs of about 1 year in age were randomly divided into Groups H (underwent 70% hepatectomy) and JH (70% hepatectomy after jejunectomy=50%proximal resection of the small intestine). Three dogs in each group were euthanized at 1 week after the operation and the remaining three dogs in each group at 4 weeks. We studied effects of the jejunectomy on the remnant liver after the massive hepatectomy with hemodynamic changes, liver functions, and liver histology. Results The portal pressure in Group JH (n=6) was significantly reduced one hour after the hepatectomy in comparison with that in Group A (n=6, p=0.002). Hepatic arterial flow was significantly higher in Group JH than in Group H (p=0.004). Subsequently, the total hepatic flow also rose to a higher value in Group JH than in Group A (p=0.037). Hepatic tissue flow was significantly higher in Group JH (p=0.025). On the earlier postoperative days, AST, ALT, ALB and AT3 of Group JH were significantly better than those of Group H. Histology of the remnant liver in the early phase showed significantly more swollen hepatocytes with subsequent more apoptotic cells in Group H than in Group JH. Conclusions Our results suggest that the portal pressure control by the jejunectomy can forestall liver dysfunction in small-for-size graft syndrome after living donor liver transplantation in adults.

A study of the incidence of apoptosis in the human placental cells in the last weeks of pregnancy

A prospective study to determine whether there is a progressive increase in the number of apoptotic cells in the trophoblasts in the placentae of the final few weeks (39 - 41 weeks) of human uncomplicated pregnancy was carried out at a teaching hospital in Sri Lanka between July 1999 and July 2001. Thirty placentae were collected at delivery following uncomplicated singleton pregnancies. The gestation of 15 were from 37 and 1 day to 39 weeks (Group 1) and the other 15 were from 39 and 1 day to 41 weeks (Group 2). There was no difference in the age, parity and birth weights in the two groups. The mean (SD) of the percentages of apoptotic cells in Group 1 and Group 2 were 1.15% (0.15) and 1.64% (0.16), respectively. The difference was statistically significant. There is a definite increase in apoptosis from 39 - 41 weeks in uncomplicated pregnancy.

Pathogenetic roles of angiogenic factors in pyogenic granulomas in pregnancy are modulated by female sex hormones.

An abundance of microvessels is the major phenotype of pyogenic granuloma, which has been considered a hormone-related lesion based on clinical observations. Although angiogenic factors and inflammatory cytokines have been implied to play roles in the pathogenesis of pyogenic granuloma, their links to female steroid hormones still remain to be elucidated. Since apoptosis is important in limiting inflammation, we also investigated whether steroid hormones could protect granuloma cells from apoptosis and, therefore, lead to overreactive inflammatory response. We employed immunoassays in a series of experiments, including human pyogenic granuloma in pregnancy, mouse air pouch granuloma and U937 (monoblastoid) cells in culture to clarify the relationship among vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta and female steroid hormones in granuloma formation. The apoptotic rates were analyzed in vivo and in vitro by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling (TUNEL) and flow cytometry, respectively. Both in human and animal studies, the immunoassays (enzyme-linked immunoabsorbent assay [ELISA] and immunohistochemistry) detected significantly more VEGF and bFGF and less TNF-alpha in hormones than the control group, while TUNEL assay revealed less apoptotic cells in groups with pregnancy levels of hormones. In vitro, progesterone enhanced the expression of VEGF in LPS-treated U937 cells. Both estrogen and progesterone inhibited the apoptosis of U937 cells triggered by exogenous TNF-a Female steroid hormones may have dual effects on the pathogenesis of pyogenic granuloma in pregnancy. The hormones not only enhance the expression of angiogenic factors in inflamed tissue, but also decrease apoptosis of granuloma cells to extend angiogenic effect.

Role of apoptosis in uranyl acetate-induced acute renal failure and acquired resistance to uranyl acetate

We have previously reported that animals recovering from uranyl acetate (UA)-induced acute renal failure (ARF) were resistant to subsequent insult. Recent evidence suggests that apoptosis participates in tubular damage. We investigated the role of apoptosis in UA-induced ARF and attenuation of ARF in acquired resistance to UA in rats. ARF was induced by an intravenous injection of UA (5 mg/kg) in rats. Rats of group 1 were injected with UA and followed for 28 days. Group 2 rats were injected with a second dose of UA (5 mg/kg) 14 days after the first injection and were followed for 14 days. All rats received an intraperitoneal injection of bromodeoxyuridine (BrdU) one hour before sacrifice. Using kidneys, histologic examination and immunohistochemical detection of proliferating cell nuclear antigen (PCNA), BrdU, Bcl-2, and Bax were performed. To detect apoptosis, electron microscopy, analysis of DNA fragmentation, and the TUNEL methods were adopted. UA increased the number of damaged renal tubules and serum creatinine, which peaked at 5 days in group 1, but both returned to baseline values by 14 days. Apoptosis was confirmed by electron microscopy and the "ladder" pattern of DNA fragments on gel electrophoresis. The number of apoptotic tubular cells evaluated by the TUNEL method showed two peaks at days 5 and 14 in group 1. The second peak of TUNEL-positive cells was preceded by an increased number of BrdU-positive nuclei, PCNA-positive nuclei, and total number of tubular epithelial cells. Renal damage after the second UA injection was markedly reduced. The peak number of apoptotic cells in group 2 was significantly less than that in group 1. Two peak levels of apoptotic cells occurred in UA-induced ARF. The first peak might play a role in UA-induced tubular damage, while the second one might represent the removal of excess regenerating cells during the recovery phase. Modulation of apoptotic cell death might be involved in the acquired resistance to rechallenge injury by UA.