【ABSTRACT】 BACKGROUND AND AIM: To explore the effects of subchronic exposure to di-n-butyl phthalate(DBP)on testicular insulin-like factor 3 (Insl3)mRNA expression in pubertal male rats. MATERIALS AND METHODS: A total of 72 male Sprague-Dawley rats at the age of 4-5 weeks were equally randomized into 3 groups, to receive by gavage 0,50 or 250 mg/kg of DBP on alternate day for 90 days. Body, testis , epididymis and main organs were weighed. Serum testosterone, and mRNA expression of Insl3 in the testis were measured. RESULTS: There was an increase of the liver/body ratio in 250 mg/kg group after 90 days treatment(P<0.05). Compared with the control, an increase in serum testosterone was found in the 50 mg/kg group(P<0.05), but there was a reduction in 250 mg/kg group compared with the 50 mg/kg group(P<0.01)after 60 days exposure. The mRNA expressions of Insl3 were significantly down regulated in all dosage groups(P<0.01), more significantly in 250 mg/kg group than in 50 mg/kg group(P<0.05). CONCLUSION: Pubertal male rats subchronically exposed to DBP could induce changes in serum testosterone and testicular Insl3 mRNA expression,and could have potential adverse effect on the liver.

BACKGROUND AND AIM: To investigate the combined effects of di-n-butyl phthalate (DBP) and benzo(a)pyrene (BaP) on vimentin and α-tubulin in rat sertoli cells. MATERIALS AND METHODS: Rat testicular sertoli cells were isolated, purified and cultured , then treated with the toxins at different doses, DBP(1,10,100 μg/ml), BaP (0.1,1, 10 μg/ml) and DBP＋BaP (1＋0.1,10＋1,100＋10 μg/ml), for 12 h,24 h and 48 h. The vimentin and α-tubulin were measured with immunofluorescence technique. RESULTS: At 24 h, the expressions of vimentin protein in 10 μg/ml DBP group and 1 μg/ml BaP group were decreased significantly (P<0.05), and lower in 100 μg/ml DBP group (P<0.01), 10 μg/ml BaP group (P<0.01) and 100 μg/ml DBP＋10 μg/ml BaP group(P<0.01). At 48 h, the expressions of vimentin protein in middle and high dose of DBP group and BaP group and all three combined groups were obviously decreased, but there was no difference between each combined group and their matched dose group. The expression of α-tubulin protein was increased significantly in 10 μg/ml BaP group(P<0.05) at 24 h and in 100 μg/ml DBP group and each BaP groups at 48 h. CONCLUSION: DBP and BaP could decrease vimentin protein expression and increase α-tubulin protein expression at certain dosages, and their combined effect on these two proteins in rat sertoli cells were antagonistic.

BACKGROUND AND AIM: To investige the effects of Di-n-butyl phthalate on the multiplication function of F0 and F1 pregnancy rats and on the development and reproductive system of F1 and F2 male pups. MATERIALS AND METHODS: Pregnant SD rats were randomly divided into three groups with two experimental groups and one control group. Animals were gavaged with either corn oil only (vehicle control) or DBP[50 mg/(kg•d),250 mg/(kg•d)] during GD8 and GD21. For breeding in two generations, we assessed the body weight, sex ratio of F0 and F1 pregnant rats. The body weight, anogenital distance, number and morphous of sperm, the histology of testis or epididymis of F1 and F2 male pups were also observed. RESULTS: Compared with control, the body weight gain during lactation of F1 pregnant rats were significantly increased at the dose of DBP 50 mg/(kg•d), but the anogenital distance were shorten in F2 female pups. After corrected by anogenital index(AGI), there are no significant differences. At the dose of DBP 250 mg/(kg•d), the body weight gain during lactation of F0 pregnant rats were significantly reduced. The anogenital index and the number of sperm of F1 male pups were also significantly reduced at this dose(P<0.05 or P<0.01). Moreover, the headed deformity rate of F1 and F2 male pups were also reduced significantly(P<0.05). CONCLUSION: Treating with DBP in utero could interfere with the multiplication function of F0 and F1 pregnant rats, and give rise to the reproductive toxicities of F1 male rats, with potential influence on F2 male rats.

BACKGROUND AND AIM:To explore therapeutic effects of IFN-γ combined with glucocorticoid on pulmonary fibrosis in mice. MATERIALS AND METHODS: Mice were divided into five random groups: negative control(NS)group; model(bleomycine, BLM)group; dexamethasone (DXM) treatment group; IFN-γ treatment group; DXM combined IFN-γ treatment group. To establish the pulmonary fibrosis model, the last four groups received BLM intratracheally at a dose of 3 mg/kg, NS group received NS by the same way. From 1st day after BLM treatment, DXM group and combined group were treated with 20 mg/kg DXM subcutaneously. And from 15th day after BLM treatment, IFN-γ and combined groups were treated with IFN-γ 0.01 μg/g subcutaneously. After the different treatments, animals were killed at 22nd day. The pathological changes were examined, hydroxyproline content (Hyp)was assayed by acid hydrolyzation, TNF-α expression was shown by IHC, and GSH/GSSG ratio, MDA content as well as T-SOD activity were determined by fluorimetry. RESULTS: Pathological score and Hyp content of combined group were both significantly lower than BLM and individual treatment groups(P<0.05). TNF-α expression was highest in IFN-γ treatment group, while that of combined group was between the BLM and DXM treatment groups. Compared with BLM and individual treatment groups, GSH/GSSG ratio was higher but MDA content was lower in combined group(P<0.05). T-SOD activities were not significantly different among groups(P>0.05). CONCLUSION: The results indicated the effects of DXM combined with IFN-γ was better than their individual effect.

BACKGROUND AND AIM: To study the changes of peroxisome proliferator-activated receptor γ (PPAR-γ) expressions at different time points in rat lung after phosgene exposure and explore the role of PPAR-γ in this pathogenesis. MATERIALS AND METHODS: 60 male rats were randomly divided into 6 groups with 10 in each group. The six groups were: negative group exposed to room air and the positive groups exposed to 38.08 mg/L phosgene for 1 minute. The five positive groups of rats were exposed to phosgene in the same dose and same time, but rats were killed 1,3,6,12 and 24 hours after exposure. The expressions of PPAR-γ mRNA and TNF-α mRNA in lung were measured by RT-PCR, PPAR-γ protein by Western-blot, and the TNF-α content by ELISA. RESULTS: With prolonged time after phosgene poisoning, compared with control rats, W∶D lung weight ratio significantly increased (P<0.05). The expression of lung TNF-α mRNA increased markedly(P<0.05). PPAR-γ mRNA expression in lung decreased at 1 h after phosgene exposure, and declined to the lowest level at 3 h after exposure. PPAR-γ protein in lung significantly decreased in positive groups, declined to its lowest point in 3 h, then gradually increased(P<0.05). CONCLUSION: Expressions of PPAR-γ mRNA and its protein in lung were decreased significantly after phosgene exposure. This may be related to the inflammation induced by phosgene.

BACKGROUND AND AIM: The inhibition effect of periplocin extracted from cortex periplocae (CPP) on proliferation of colorectal cancer cell line SW480 was studied in vitro and in vivo. MATERIALS AND METHODS: The inhibitiory effects of different concentrations of CPP (0.125,0.25,0.5,1.0,2.0 μg/ml) on the growth of SW480 cells in vitro were measured by MTT assay. The cell morphology and microstructural changes of apoptosis were examined under light microscope and electron microscope after SW480 cells were treated with CPP(0.5 μg/ml) for 24 h. Survivin expression in SW480 cells was analyzed by immunohistochemistry after cells were treated with CPP (0.5 μg/ml) for 24 h. Model of transplanted tumor on nude mouse were used to study the anticancer effect in vivo. Control group was included in all experiments above. RESULTS: CPP significantly inhibited the proliferation of SW480 cells in a dose- and time-dependent manner in vitro (P<0.01). After treatment with CPP, SW480 cells showed some typical morphologic features and microstructural changes of apoptosis. And the expression of Survivin in SW480 cells was suppressed. After treatment with CPP 30 mg/kg for SW480 cell tumor-bearing mice, the inhibition rate of transplanted tumor was significantly increased at 61.41％. Inflammatory cells and noticeable necrosis were found in transplanted tumor tissue of CPP treated group. CONCLUSION: CPP had significant inhibitory effect on colorectal cancer cell line SW480. The mechanism maybe associated with CPP inhibiting the expression of Survivin in SW480 cells and inducing cell apoptosis.

BACKGROUND AND AIM: To study the characteristics of cytogenetic alterations of lung epithelioid hemangioendothelioma. MATERIALS AND METHODS: Whole DNA was isolated from two formalin-fixed and paraffin-embedded tissues of lung epithelioid hemangioendothelioma. The DNA copy number changes were measured by array-comparative genomic hybridization(array-CGH). RESULTS: Two epithelioid hemangioendotheliomas showed many similar DNA copy number changes. Gains of small fragments(<10 Mb) were the most frequent change while deletions were infrequent.There were 150 and 556 genes involved with 77 sharing common changes. CONCLUSION: Amplifications of small fragments of DNA maybe the main cytogenetic alteration in lung epithelioid hemangioendothelioma, which may explain that epithelioid hemangioendothelioma is a low-grade malignant tumor.

BACKGROUND AND AIM: To study the growth inhibition effect of Vitamin E succinate(VES) on SGC-7901 cells, and explore SGC-7901 VES-induced apoptosis and its possible mechanism. MATERIALS AND METHODS: After SGC-7901 cells were treated with 0,5,10,20 μg/ml VES and 1 mmol/L of mannitol＋20 μg/ml VES(cells were treated with 1 mmol/L of mannitol for 2 hours, then with 20 μg/ml VES for 24 hours) for 24 h MTT, single-cell gel electrophoresis and flow cytometry were used to detect the oxidative damage and apoptosis induced. The corresponding detection kits were used to measure the reactive oxygen species and glutathione content. RESULTS: 0, 1.25, 2.5, 5, 10, 20 μg/ml of VES inhibited cell growth to different degrees. 20 μg/ml VES inhibited cell growth to the greatest degree of 76.91％. With increasing concentration of VES, apoptosis showed an upward trend. In single-cell gel electrophoresis, with increasing VES concentration, the comet tail length and the comet rate showed a rising trend. Compared with the negative control group, glutathione content of cells in 10 and 20 μg/ml VES groups were significantly decreased, while the active oxygen content were significantly increased. 1 mmol/L of mannitol could significantly reduce DNA damage and apoptosis caused by VES, while lowering the cell oxygen and glutathione contents significantly. CONCLUSION: VES could significantly inhibit SGC-7901 cell growth in a dose-depedent manner. Oxidative damage caused by increased oxygen content and glutathione depletion may be one of the mechanisms of apoptosis induced by VES.

BACKGROUND AND AIM: We investigated the relationship between the expression of DNA methyltransferase(DNMT) and multidrug resistance gene ABCG2 in breast cancer, in order to further study the epigenetic mechanism of ABCG2 expression. MATERIALS AND METHODS: Use real-time transcription-PCR(RT-PCR) to quantify DNMTs and ABCG2 mRNA expressions in 22 breast cancer and their matching adjacent tissues. We also used Spearman rank test to analyze the relationship between mRNA levels of the DNMTs and target gene ABCG2 involved in the DNMT pathway. RESULTS:Compared with adjacent tissues, the mRNA expressions of DNMTs and ABCG2 were markedly higher in breast cancer,especially DNMT3B,which was significantly higher than that of DNMT1 and DNMT3A. There was a negative relationship between DNMT3B and ABCG2(r=-0.664,P<0.01) in breast cancer. CONCLUSION:DNMT3B may play an important role in the epigenetic mechanism of ABCG2 expression in breast cancer,providing new scientific basis for searching the therapeutic target to reverse the multidrug resistance caused by ABCG2.

BACKGROUND AND AIM: To investigate the relationship between the inactivation of maspin gene and breast cancer. MATERIALS AND METHODS: The expression of Maspin protein in breast cancer tissue, adjacent non-tumor tissue, and distal normal tissue from 30 cases were detected by immunohistochemical method. The CpG islands methylation states of maspin promoter in breast cancer tissue were studied by bisulfite sequencing PCR (BSP). RESULTS: The protein expression levels of maspin in breast cancer were significantly lower than that in adjacent non-tumor tissue (P<0.05), and in distal normal tissue (P<0.01). The methylation incidence of maspin gene promoter CpG islands in breast cancer tissue was 98.72％. CONCLUSION: These findings suggest a close correlation between the inactivation of maspin gene and breast carcinogenesis. The aberrant methylation of promoter maybe is important mechanism of maspin gene inactivation in human breast carcinogenesis.

BACKGROUND AND AIM: To explore the effect of thioglycolic acid(TGA) on mouse ovulation and in vivo maturation of oocytes. MATERIALS AND METHODS: Kunming mice were used in this study. In each experiment twelve mice were allocated to four groups,control, 37.812 5, 75.62 5 and 151.25 mg/kg TGA groups. The mice received various doses of TGA percutaneously, and intraperitonea 10 IU human chorionic gonadotrophin simultaneously 14 hours later the number of ovulated oocytes was counted. Immunofluenscence staining was used to label spindle and cortical granule (CG) in the matured oocytes. RESULTS: Compared to the control, only 151.25 mg/kg TGA group showed significantly decreased ovulated oocytes(P<0.01), and also significantly lower than that in 37.812 5 mg/kg group(P<0.05). The spindle in control and 37.812 5 mg/kg groups were bipolar, but had a barrel configuration in 75.625 mg/ml and 151.25 mg/ml groups. The area of spindle increased with increasing TGA dose. TGA had no significant influence on the distribution of CGs and the formation of cortical granule-free domain(CGFD). CONCLUSION: Percutaneous administration of TGA inhibited ovulation of mouse and inhibited oocyte maturation in vivo.

BACKGROUND AND AIM: To study the effect of indole-3-carbinol(I3C) in CNE cells as well as the underlying mechanisms. MATERIALS AND METHODS: The inhibition of cell proliferation was assayed by WST-1 agent, and the apoptosis was shown with Hochest 33258 and TUNEL staining. To study the mechanism of apoptosis, the expression of the cleaved caspase-9 and the cleaved caspase-3 were detected with western immublotting assay. RESULTS: I3C could inhibit the proliferation of CNE cells and apoptosis could be induced by I3C in a dose-dependent manner. Furthermore, the expressions of cleaved caspase-9 and cleaved caspase-3 appeared to be increased significantly as compared with those of the control. CONCLUSION: I3C could induce apoptosis of CNE cells dose-dependently, and caspase-9 and caspase-3 pathways might be involved.

BACKGROUND AND AIM: To explore the effect of selenium on arsenic-induced cell cycle changes by regulation of activator protein-1 (AP-1). MATERIALS AND METHODS: JB6-CI41 cells were exposed to sodium selenite alone at the concentrations of 2.5 μmol/L or combined with arsenous acid at the concentrations of 3.125, 6.25, and 12.5 μmol/L. The AP-1 DNA binding activity and cell cycle were analyzed by electrophoretic mobility shift assay (EMSA) and flow cytometry. Meanwhile, curcumin (20 μmol/L), a specific inhibitor of AP-1, was used to treat JB6 cells together with arsenous acid(12.5 μmol/L) in order to understand the relationship between arsenic-induced cell cycle changes and AP-1 DNA binding activity. RESULTS: Compared with solvent control, arsenous acid (3.125, 6.25 and 12.5 μmol/L) could significantly up-regulate AP-1 DNA binding activity and reduce G1 phase cells (P<0.01,P<0.01), and higher concentrations of arsenous acid (6.25 and 12.5 μmol/L) increased G2 phase cells (P<0.05,P<0.01). Sodium selenite (2.5 μmol/L) showed no effect on AP-1 DNA binding activity and cell cycle(P>0.05,P>0.05). Compared with corresponding concentrations of arsenous acid, co-exposure of JB6-CI41 cells to sodium selenite (2.5 μmol/L) and arsenous acid (3.125,6.25 and 12.5 μmol/L) down-regulated AP-1 DNA binding activity (P<0.01), increased G1 phase cells (P<0.01), and decreased G2 phase cells (P<0.05). Co-exposure of JB6-CI41 cells to curcumin and arsenous acid could significantly down-regulate AP-1 DNA binding activity, increased G1 phase cells and decreased G2 phase cells compared with corresponding concentrations of arsenous acid(all P<0.01). CONCLUSION: Arsenic may change cell cycle by activating AP-1 signal pathway. Certain concentration of selenium could down-regulate arsenic-induced AP-1 DNA binding activity, which may be one of the mechanisms that selenium could antagonize the carcinogenetic property of arsenic.

BACKGROUND AND AIM: To study the alteration of CYP1B1 gene expression in ovarian cancer cell HO-8910 after PTX chemotherapy in vitro, which can help us study the relationship between CYP1B1 gene expression and drug-resistance of cancer cells. MATERIALS AND METHODS:Ovarian cancer cells HO-8910 were cultured by tumor cell culture technique, inhibition of ovarian cancer cell growth induced by different concentration of PTX was assessed by methyl thiazolyl tetrazolium(MTT). Alterations of CYP1B1 mRNA and protein expression were evaluated by reverse transcription polymerase (RT-PCR) and Western blot in ovarian cancer cells cultured with PTX of 5 μg/ml for 24 h,48 h and 72 h or 50 μg/ml for 24 h. RESULTS: PTX inhibited the growth of ovarian cancer cell HO-8910, the inhibition rates by different concentrations of PTX after 72 h were 89.10％,76.82％,67.39％,57.27％,46.21％,37.02％,17.56％. The rate of cell inhibition decreased accordingly with the PTX concentration. In the surviving cells that had been cultured in PTX ,the expression of CYP1B1 mRNA and protein increased compared with control group. The CYP1B1 expression increased more in groups that had been treated with 5 μg/ml PTX for 48 h,72 h and 50 μg/ml compared to 5 μg/ml for 24 h group. CONCLUSION: CYP1B1 gene was highly expressed in ovarian cancer cell line, CYP1B1 gene may play an inhibitory role in PIX treatment of ovarian cancer cells HO-8910 in vitro.

BACKGROUND AND AIM: To study the effects on reproduction of male rats caused by the new antitumor compound, MC004. MATERIALS AND METHODS: 48 healthy and mature Wistar rats were randomly divided into 4 groups with 12 in each group. The rats of control group were given intravenous injections with normal saline and the exposure groups received MC004 at doses of 0.25，0.50 and 0.75 mg/kg. All rats were injected once in two days. All 48 rats were sacrificed after 28 days. Sperm motility was analyzed by a computer-assisted sperm analysis system and the sperm morphology was examined by microscope. RESULTS: The body weight was slowly increased and there was a significant difference between the dose of 0.75 mg/kg and the control group. Both the absolute weight and the organ weight to body weight ratios for testis and epididymis were significantly decreased(P<0.01). The epididymal cauda sperm number and the motility of the sperms were significantly decreased by MC004 treatment, while the rate of abnormal sperms was increased(P<0.01). CONCLUSION: When the male rats were treated with intravenous MC004 once in two days for 28 days, there was significant reproductive toxicity at the dose of 0.25 mg/kg.

BACKGROUND AND AIM: To explore the cytotoxicity and genotoxicity of beryllium sulfate to human embryonic lung fibroblast (HEL-I)in vitro .MATERIALS AND METHODS: HEL-I cells were cultured with different concentrations of beryllium sulfate for 24 h, cell survival rate was measured by MTT test, cell genetic damage was assessed by single-cell gel electrophoresis and micronucleus test . RESULTS: The survival rate of HEL-I cells decreased along with increasing concentrations of the beryllium sulfate . When the concentration of beryllium sulfate reached 100.0 μmol/L and 200.0 μmol/L， the survival rates of HEL-I cells were lower than control group. And beryllium sulfate caused DNA damage and micronucleus rate elevations in HEL-I cells at concentrations between 2.0 μmol/L and 100.0 μmol/L (P<0.05). CONCLUSION: Beryllium sulfate had obvious cytotoxicity and genotoxicity in HEL-I cells.

BACKGROUND AND AIM: To explore the role of JC virus early region gene encoding product large tumor antigen(T-Ag) and the interaction between T-Ag and tumor suppressors P53 and pRb in human colorectal adenocarcinoma. MATERIALS AND METHODS: The expression of JCV T-Ag and P53 and pRb proteins were evaluated by immunohistochemistry PV method in 77 cases of human colorectal adenocarcinoma , 20 colorectal adenomas and 20 normal colorectal mucosa. RESULTS: The positive rate of JCV T-Ag 、P53 and pRb proteins were 36.4％、61.0％and 55.8％,respectively, in 77 cases of human colorectal adenocarcinoma , and there was an obvious difference when compared with colorectal adenomas and normal colorectal mucosa (P<0.05).There was no statistically significant links between the presence of T-Ag and pT, pN, pM or differentiation degree(P<0.05). P53 was closely correlated to differentiation degree(P<0.05),but was not correlated to the age, site, p-TNM and lymph node metastasis(P>0.05). pRb was closely correlated to p-TNM and lymph node metastasis(P<0.05).There was statistically significant correlation among the expression of T-Ag and P53、pRb protein (r=0.272，r=0.237，P<0.05). CONCLUSION: JCV was closely related to colorectal adenocarcinoma. Its encoding product in the large T antigen played an important role in the carcinogenic process.

BACKGROUND AND AIM: To study toxicokinetics of CXY-001 in Beagle dogs, and evaluate the relationship between exposure response and dose. MATERIALS AND METHODS: Samples were analyzed with a validated LC-MS-MS method. In single dose study, the dosages of CXY-001 were 227, 511, 767, 1150 mg/kg . Blood samples were collected at 0.5, 1,2,3,4,5,6,8, 24 h after administration. In the 90-day repeated dose study, CXY-001 dosages were 120,30 and 7 mg/kg . On day 1, blood samples were collected at 0.5, 1,2,3,4,5,6,8, 24 h after administration. On day 45, blood samples were collected at 0.5,5,24 h and on day 90 at 30 min, 5,24,48,72 h. RESULTS: In single dose study, vomiting was observed. The CXY-001 AUC0-24 for doses 227,511,767,1 150 mg/kg were 150 249,263 905,232 640 and 19 848 ng•h/ml,respectively. The AUC0-∞ were 151 054, 298 069, 246 083 and 117 793 ng•h/ml,respectively. The Cmax were 13 400, 19 500, 29 100 and 6 910 ng•h/ml, respectively. In repeated dose study, the No-Observed-Adverse-Effect-Levle was 30 mg/kg. On day 1, the CXY-001 AUC0-24 for doses 120,30 and 7 mg/kg were (123 023±75 308),(19 246±14 654) and (2 991±996) ng•h/ml,respectively. AUC0-∞ were (200 189±106 688),(25 145±22 443) and (4 650±1 855) ng•h/ml,respectively. Cmax were (10 440± 5 891), (3 653±1 776) and (376±116) ng•h/ml, respectively. There was a slight difference of CXY-001 concentration at the same time point on day 45 and day 90,and CXY-001 concentration was below the low limit of quantitation at 48 h after last dose. CONCLUSION: Exposure response to CXY-001 generally increased with increasing dosage in Beagle dogs following oral dosing. These data suggest no accumulation was observed after stopping CXY-001 administration.

BACKGROUND AND AIM: To obtain and identify cultured granulosa cells from the ovary of rats so as to establish a convenient and stable experimental model. MATERIALS AND METHODS: Female SD rats were subcutaneously treated with pregnant mare serum gonadotropin (PMSG). Forty-eight hours after dosing with PMSG, the animals were decapitated and the ovaries were aseptically removed. Granulosa cells were then released by mechanical method, trypsin digestion and low-speed centrifugation separation were used for granulosa cells isolation. Granulosa cells were diluted and incubated in fresh DMEM-Ham's F-12 medium (1∶1) containing 15％ of fetal bovine serum at 37 ℃ in water-saturated environment of 5％ CO2. Hematoxylin ＆ Eosin (HE) and immunohistochemical staining of FSHR were used for ovarian granulosa cell identification. Additionally, the growth curves of granulosa cells and hormone levels at different incubation times were evaluated as well. RESULTS: Over 95％ of the cultured cells were ovarian granulosa cells．The exponential phase of growth was between 48 and 96 hours of incubation. CONCLUSION: More than 95％ of highly purified granulosa cells could be obtained by mechanical method combined with trypsin digestion and low-speed centrifugation. Moreover, identifications of granulosa cells by HE and FSHR staining were quick and convenient approaches.

BACKGROUND AND AIM: To establish an intradermal model with transplanting melanoma B16 cells in C57BL mice． MATERIALS AND METHODS: commercially-acquired 3×106 B16 cells in 0.1 ml were inoculated intradermally in the right hindlimb in C57BL mice．B16 cells from tumors were isolated, cultured and examined. RESULTS: Tumor formation time was found to be (9.6±1.2)d and tumor formation rate was 100％. Within 18 d, tumors was round or round-like shape with distinct borders. Commercially-acquired B16 cells were mostly spindle or irregular whilst B16 cells from tumors were round or round-like or short-spindle. HE staining showed that there were a large number of B16 cells in the transplanted tumors. CONCLUSION: Intradermal tumor model of B16 cells in C57BL mice is helpful to monitor tumor growth in early and middle stages and is one of ideal models in tumor studies.

BACKGROUND AND AIM: To study the potential mutagenicity of piperine. MATERIALS AND METHODS: Micronucleus assay, chromosomal aberration test and sperm toxicity assay of mice were studied. RESULTS: The ratios of micronucleus cells with piperine 574 mg/kg ,287 mg/kg were increased compared with negative control .There were significant chromosomal damages with the piperine concentration of 574 mg/kg,287 mg/kg and notable sperm abnormalities with the piperine concentrations of 574 mg/kg,143 mg/kg compared with negative control. CONCLUSION: Piperine demonstrated mutagenicity in rats in this experimental system.