Document vB5OZ4vamkMBnDY8Z9BYKzgJR

AR226-3392 Subchronic Toxicity 90-Day Oral Gavage Study of of 8-2 Telomer B Alcohol in Rats G.S. Ladies,' G.L. Kennedy,' J.C. O 'Connor,' N.E. Everds,' L.A. Malley,' S.R. Frame,' S.A. Gannon,' R. Jung,2 H. Iwai,3 M. Shinohara4 Telomer Research Toxicology Program The DuPont Company, Haskell Laboratory fo r Health and Environmental Sciences, Newark, Delaware, USA Clariant GmbH, Sulzbach, Germany Daikin Industries, Inc., Osaka, Japan Asahi Glass, Co., Ltd., Tokyo, Japan PIBAbstract 8-2 Telomer B Alcohol (8-2 TBA) is a fluorinated chemical intermediate used to manufacture specialty polymers and surfactants- The potential subchronic toxicity and the reversibility o f the effects o f this chemical were evaluated following approxim ately 9 0 days o f oral gavage dosing to Crl:CD(SD)lGS BR rats. A complete toxicology profile including neurobehaviorai assessments and hepatic J3oxidation were conducted at selected intervals and a group o f rats was included for a 90-day post-dosing recovery period. Dose levels tested were 0 (control), 1, 5 ,2 5 . and 125 mg/kg/day. N o test-substance-related mortality occurred. Rats at 125 mg/kg/day developed striated teeth such that these animals were switched to ground chow at 77 days. No treatment-related alterations in body weight, food consumption, neurobehaviorai parameters, or hematology/clinical chemistry were found. Hepatic |J-oxidation was increased in males at 125 mg/kg/day and in females a t 25 mg/kg/day. In both males and females, plasma fluorine levels were significantly increased at 125 mg/kg/day and urinary fluorine was elevated at > 5 mg/kg/day. Dcgeneration/disorganization o f enamel organ ameloblast cells was seen in males, but not females at 125 mg/kg/day. Liver weight increases accompanied b y focal hepatic necrosis were seen at both 25 and 125 mg/kg/day in males and chronic progressive nephrotoxicity occurred in females administered 125 mg/kg/day. With the exception o f hepatocellular necrosis observed in males administered 125 mg/kg/day and the incidence and severity of chronic progressive nephropathy in the 125 mg/kg/day female group, which increased after 3 months, all other changes showed evidence o f reversibility. T he no-observed-adversc-cffect level for the 90-day study was 5 mg/kg/day. H I Introduction The test substance, 8-2 Telomer B Alcohol, is an organofluorine compound- The 1, 5 ,2 5 , and 125 mg/kg/day dose levels for this study were selected based on the toxicity observed in an 84-day range finding study with 5 ,2 5 , and 125 mg/kg/day 8-2 Telomer B Alcohol (2004 SOT Abstract #778) and subchronic studies with similar fluorotelomer-based alcohols and perfluorooctanoic acid (PF O A )."1 ' 41 I Objective The objective o f this study is to evaluate the potential subchronic toxicity and reversibility o f 8-2 Telomer B Alcohol when administered by gavage to male and female rats. T he oral route o f administration was selected as the most efficient way to deliver an accurate dosage. I Experimental Design Five groups o f young adult male and female Crl'.CD(SD)lGS BR rats were administered 8-2 Telomer B Alcohol daily by gavage at dosages o f 0 , 1 ,5 ,2 5 , and 125 mg/kg/day for approxim ately 90 days. Body weights, food consumption, and clinical signs were evaluated weekly. Clinical pathology samples w ere collected on weeks 7 ,1 3 , and near the end o f the 3-month recovery period for hematology, clinical chemistry, urinalysis, coagulation (end o f study only), and plasma and urine fluoride (end o f study and 3-month recovery period). Neurobehaviorai assessments were also perform ed prior to dosing and during week 13. Biochemical evaluations (hepatic p-oxidation) were perform ed on animals after 10 and approxim ately 90 days o f dosing and following the 3-month recovery period. After approximately 90 days o f dosing, 10 rats/sex/dose were sacrificed and given a gross and microscopic pathology examination. Approximately 3 months after the 90-day dosing period, 10 animals/sex in the control and high dose group were examined for recovery of toxic effects. H U Results In-Life Toxicology Parameters No test substance-related mortality occurred in the study. A test substance-related, toxicologically significant increase in the incidence of striated teeth was observed in the 125 mg/kg/day male and female dose groups. O n test day 77, ait male and female high dose animals were placed on ground chow due to test substanceinduced alterations to the teeth. There were no test substance-related, toxicologically significant alterations in body weight, body weight gain, food consumption, o r food efficiency observed in any o f the male or female dose groups. Ncurotoxicology Parameters No adverse changes in neurobehaviorai parameters were observed in male or female rats in any dose group. Biochemical Toxicology The rale of hepatic p-oxidation, a measure of peroxisome proliferation, was significantly increased in females administered 25 mg/kg/day 8-2 Telomer B Alcohol and in males and females administered 125 mg/kg/day 8-2 Telomer B Alcohol. Following a 3-month recovery period, the rate of hepatic p-oxidation' lower but still significantly increased in males administered 125 mg/kg/day 8-2 Telomer B Alcohol, and had returned to control levels in female rats. Clinical Pathology There were no toxicologically significant changes in clinical pathology parameters observed in rats dosed with up to 125 mg/kg/day 8-2 Telomer B Alcohol. Plasma fluoride levels were significantly increased in males and females dosed with 125 mg/kg/day, but returned to control levels following 3 months o f recovery. Urine fluoride excretion was significantly increased in males and females dosed with > 5 mg/kg/day and > 25 mg/kg/day, respectively. After 3 months of recovery, urine fluoride levels in females returned to control levels, while levels in males were significantly reduced compared to those at die end of the exposure period. Increased plasma and urine fluoride indicates exposure to and metabolism o f a fluorine-containing compound. The presence of fluoride after 90 days o f recovery indicates continued metabolism of the test substance. Anatomic Pathology Test substance-related, toxicologically significant degeneration/disorganization of enamel organ ameloblast cells occurred in male rats administered 125 mg/kg/day 8 2 Telomer B Alcohol. In addition, alterations in thyroid colloid were observed in male and female rats at all dose levels. Because altered colloid occurs spontaneously in healthy Sprague-Dawiey rats,(S) and since there were no other microscopic alterations in the thyroid gland, altered colloid was interpreted as not biologically meaningful and non-adverse. A test substance-related, biologically adverse increase in the incidence and severity o f focal hepatic necrosis was observed in males administered 25 and 125 mg/kg/day. An increased incidence and severity of chronic progressive nephropathy occurred in the 125 mg/kg/day female group that was considered adverse. Test-substance related and statistically significant increases in liver weight parameters were present in males and females administered 25 or 125 mg/kg/day for approximately 90 days. The increased liver weightscorrelatcd with microscopic hepatocellular hypertrophy in die 125 mg/kg/day male dose group. Hepatic enzyme levels, however, were not elevated. Test-substance related and statistically significant increases in kidney weight parameters occurred in males administered 25 mg/kg/day and males and females administered 125 mg/kg/day. The increased kidney weights correlated with microscopic renal tubular hypertrophy in the 25 and 125 mg/kg/day male groups only. However, there was no histomorphologic evidence o f renal damage, and renal clinical pathology parameters were not indicative o f adverse effects. After 3 months o f recovery, rats dosed with 125 mg/kg/day showed reversibility of some effects. H ie ameloblastic degeneration/disorganization persisted with decreased incidence and severity in the 125 mg/kg/day male group. Increased liver weight parameters and hepatocellular hypertrophy (males only) were no longer observed in die 125 mg/kg/day male and female groups. However, the incidence of hepatocellular necrosis in die 125 mg/kg/day male group increased after 3 months of recovery. Increased kidney weight parameters and renal tubular hypertrophy (males only) were not observed in rats sacrificed after 3 months of recovery. In contrast, the incidence and severity of chronic progressive nepiiropathy were increased in the 125 mg/kg/day female group following 3 months o f recovery. Summary of Peroxisomal fl-Oxidatimi Activity In Male Unis Omg/kg/day HepaticPeroxisomal p-OxidelionActivity (nmol/min/mcprotein)____ ___ IQ-Pay_____ 90-Dav 3-MonthRecovery 148a l u Jd.4x 1.4 11.2x1.8 1mg/kg/day* 14.0x1.7 13.6x1.5 25 mg/kg/day* )4.7sl) 13.4x2.1 r^mx/W/rtov 24.1x3.78 206x2.8* . 14.9x2.0* Summary of Peroxisomal Jl-Oxldntion Activity in Female Uats HepaticPeroxisomal (3-OxidaonActivity (luncl/min/mgprotein! _____ ]0-l>av_____ 90-Day 3-MonlhRecovery iiite Fluoride expressed as mean and as ftcixcnt of control group mean) Tctt ~ Sex Dav Ome/kc/dey 1mg/kgSiey 5raftzAlav 25me/kt/dav 125 mg/kfAky. Mean Final Body, Liver, and Kidney Weights for Male Rats alter 90-Dny Test Substance Exposure ~ OnieAe/dav i mg/kg/foy 5mzftg/dav IS mc/kf/dav 125mg/ke/day MEANFINAL BODYANDABSOLUTEORGANWEIGHTS (poms) LIVER 14876 14.109 15.575 17.219* 21.976 1770(10) 1.254(10) 1.744(10) 1.693(10) 1.928(10) KIDNEYS 3.924 3.804 4.087 4.35! 4.636* 0463110) 0.263(10) 0.501(10) 0.417(10) 0.346(10) FINALBODYWEIGHT(poms) 552.940 540.790 582650 564.140 536.980 49.145(10) 37.400(10) 46.186(10) 43.119(10) 31.734(10) MEANRELATIVEORGANWEIGHTS(S ofbodyweight) LIVER/ 2690 2.609 2669 ixxnm roan FINALBODY 100 0.225(10) 0 )40(10) 0.148(10) 0 124(10) 0410(10) KIDNEYS/ 0.712 0.707 0.702 0771 0.867 FMALBODV 100 0091(10) 0.076110) 0.069(10) 0.0)5(10) 0.096(|0)_ Mean Final Body, Liver, and Kidney Weights for Female Rais after 90-Day Test Substance Exposure Omg/kc/dav I mg/kf/dev Smata/dav 25mc/ltg/day 125mg/kg/da; MEANFINALBODYANDABSOLUTEORGANWEIGHTS(gram) LIVER . 7.90J B.224 8.185 9.230 0.849(10) 0.982(10) 0.845(10) 1.076(10) 0972(10) KIDNEYS 2.239 2 147 2155 2453 0188(10) 0239(10) 0.173(10) 0.267(10) 0265(10) FINALBODYWEIGHT(grams) 286830 294.600 294.090 297520 288.960 25304(10) 25 107(10) 25.820(10) 26.015(10) 17.911(10) MEANRELATIVEORGANWEIGHTS( ofbody weight) LIVER/ 2.755 FINALBODY 100 0 158(10) K3DNEYS/ 0782 FINALBODY* 100 0.043(10) 2790 0212110) 0732 0087110) 2.784 0.161(10) 0.734 0.043(10) 3.098 0171(10) 0.825 00S6U0) 0287(10) 0852 0064110) Incidences and Average l-esion Grades of Test snbsLuico-RcIatcd Microscopic Findings In Male and Female Unis --------------------------------------- 5 5 25 123 ______________________ rarftg/day mc/kg/day meftg/day metke/day mg/ktAley ____________ Male! 90-DayExpomre____________ Live Hypcurophy, hepatocellular 0/10*10.0)" 0/10(0.0) 0/10(00) 0/10(00) 10/10(1.6) Necrosis, focal 0/10(0.0) 0/10(0.0) 1/10(1.0) 5/10(10) 3/10(10) Hypertrophy, tubule/ 0/10(0.0) 0/10(0.0) 0/10(0.0) 9/10(1.0) 10/10(10) Alteration, colloid 3/10(1.0) 8/10(1.1) 9/10(1.0) 10/1000) 8/10(2.3) Degeneration.ameloblosts(nose) 0/10(0.0) 0/10(00) 0/10(00) 0/10(0.0) 5/10(1.6) Malea: 3-Month Reravtry___________ 3/10(1.3) NA NA NA 7/10(1.1) 7/10(1.4) NA NA NA 10/10(1.6) mcleblasuloose) 0/10(0.0) NA NA NA 2/10(1.0) Fetnalca: 90-Dny Exposure___________ sivcnephropalhy 2/11(1.0) 2/10(1-0) 3/10(1.0) 3/10(10) 7/10(1.0) Females: 3-Monlh Recovery rivenephropathy 5/9(10) NA_____ NA NA 8/10(1.4) H P .Summary Test substance-related, toxicologically significant increases in tlte incidence o f striated teeth occurred in (he 125 mg/kg/day male and female dose groups. Test subsiancerelatcd, toxicologically significant degeneration/disorganization of enamel organ ameloblasts ceils occurred in male rots dosed with 125 mg/kg/day8-2 Telomer B Alcohol. This tooth lesion, along with the increased incidence of striated teeth, is consistent with fluoride toxicosis.151 After 3 months, the degeneration/disorganization of ameloblasts persisted, at a lower incidence and severity. The observed alterations in liver and kidney weights, as well as the incident* of hepatocellular and renal tubular hypertrophy, were considered to be a pimrmacotogically adaptive response by these organs to the test substance and, tlierefore, not considered adverse.'1-*51 A statistically significant increase in the rate of hepatic p-oxidation occurred in die 2S mg/kg/day female and 125 mg/kg/day male and female groups- After Hie recovery period, the increased rale of p-oxidation persisted, albeit at a reduced level compared to the 90-day tin* point, in the 125 mg/kg/day male group. A test substance-related, toxicologically significant increase in the incidence and severity of focal hepatic necrosis was observed in males administered 25 and 125 mg/kg/day. An increased incidence and severity of chronic progressive nephropathy occurred in die 125 tng/kg/day female group that was considered adverse. After 3 months of recovery, both the incidenceof hepatocellular necrosis in the 125 ing/kg/day male group and the incidence and severity of clironic progressive nephropathy in the 125 mg/kg/day female group were increased compared to control. I P ! Conclusions The no-observed-effect level (NOEL) for males was 5 mg/kg/day 8-2 Telomer B Alcohol based on the increased incidence of hepatic necrosis observed in males administered >25 mg/kg/day. Tlte NOEL for females was 5 mg/kg/day 8-2 Telomer B Alcohol based on die increased rate of hepatic p-oxidation observed in females administered > 25 tng/kg/day. I References 1. 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