Short Communication
SHORT COMMUNICATION, Pharmacology & Toxicology 1992, 10, 392-393.
Lindane Induced Rat Liver Lipid Peroxidation Without Depressed Cu-Zn Superoxide Dismutase Activities Feili L. Yang and Robert A. DiSilvestro* Department of Human Nutrition and Food Management, The Ohio State University, Columbus, Ohio 43210, U.S.A. (Received September 2, 1991; Accepted February 4, 1992)
Lindane (r-hexachlorocyclohexane) is a pesticide widely used in developing countries. Acute lindane toxicity in rats causes biochemical and histological alterations in several sites including the liver (Junqueira et al. 1988; Videla et al. 1990). Hepatic injury is proposed to occur through elevated free radical generation combined with diminished antioxidant defenses such as superoxide dismutase, catalase and glutathione (Junqueira et al. 1988; Videla et al. 1990). Superoxide dismutase activities are reported to decrease by 6 hr after oral lindane dosing and remained depressed for at least 24 hr, with values falling by almost 50% (Junqueira et al. 1988). No distinction has been made between cytosolic Cu-Zn superoxide dismutase and mitochondial Mn superoxide dismutase (Hassan 1988). However, the sample preparation used (Junqueira et al. 1988) produces primarily cytosol, and cytosolic superoxide dismutase accounts for most of the total superoxide dismutase in liver (i.e. L'Abbe et al. 1991). The present study examined lindane effects specifically on Cu-Zn superoxide dismutase activity. No effect was found despite induction of lipid peroxidation.
Animals and experimental procedures. For fig. I , male Sprague Dawley rats (Harlan Sprague Dawley, Indianapolis, U.S.A.), 250 to 300 g, previously fed a standard mixed feed, were given 60 mg/kg, intraperitoneally of lindane in corn oil, or corn oil alone. For table 1, weanlings were fed a semipurified diet (DiSilvestro & Marten 1990) with 6 p.p.m. copper for 6 weeks. Analytical procedures. Lipid peroxidation was assessed as thiobarbituric acid reacting substances (Ohkawa et al. 1979). Cu-Zn superoxide dismutase activity was generally assayed by a modified pyrogallol method after homogenizing livers using a Brinkmann Polytron (Westbury, NY, U.S.A.), and then inactivating Mn superoxide dismutase with ethanol :chloroform (Marklund & Marklund 1974; DiSilvestro & Marten 1990). Superoxide dismutase activity was also assayed in a postmicrosoma1 supernatant (Junqueira et al. 1988), prepared from a homogenate made with a Potter-Elvehjem apparatus, using a nitroblue tetrazolium superoxide dismutase method (Beauchamp 1971). For both superoxide dismutase assays,
* To whom correspondence should be addressed.
units were the sample amounts giving 50% inhibition of color formation. Liver lipid peroxide levels were elevated by about 30%, 16 and 24 hr after lindane injection (fig. 1). This elevation was less than that reported by Junqueira et al. (1988). However, this previous study incubated oxygenated samples at 37" before reaction with thiobarbituric acid (Bernheim et al. 1948). This increases sample thiobarbituric acid reacting substances before initiating the thiobarbituric acid reaction. The method used in our study (Ohkawa et al. 1979) measures only preexisting thiobarbituric acid reacting substances. Cu-Zn superoxide dismutase activities were unchanged at three time points after lindane injection (fig. I). One possible difference between this study and that of Junqueira et al. (1988), could have been the dietary copper levels. Lindane could act like inflammation, a reducer of liver Cu-Zn superoxide dismutase activities when rats are fed 6 p.p.m. copper or less, but not when diets contain 15 p.p.m. copper (DiSilvestro & Marten 1990). However, lindane did not reduce Cu-Zn superoxide dismutase activities in rats fed 6 p.p.m. copper (table I).
-
Liver TBARS & CuZnSOD Activity of Lindane R a t s
..*. SOD
TBARS
160 150 140
0
8
16
24
Hours Fig. 1. Effects of lindane (60 mg/kg, intraperitoneally) on hepatic thiobarbituric acid reacting substances (TBARS) per g liver and Cu-Zn superoxide dismutase (SOD) activity units per g liver. Values are the means from 3 rats-frS.E.M.TBARS were significantly different from controls at 16 and 24 hr (p
SHORT COMMUNICATION, Pharmacology & Toxicology 1992, 10, 392-393.
Lindane Induced Rat Liver Lipid Peroxidation Without Depressed Cu-Zn Superoxide Dismutase Activities Feili L. Yang and Robert A. DiSilvestro* Department of Human Nutrition and Food Management, The Ohio State University, Columbus, Ohio 43210, U.S.A. (Received September 2, 1991; Accepted February 4, 1992)
Lindane (r-hexachlorocyclohexane) is a pesticide widely used in developing countries. Acute lindane toxicity in rats causes biochemical and histological alterations in several sites including the liver (Junqueira et al. 1988; Videla et al. 1990). Hepatic injury is proposed to occur through elevated free radical generation combined with diminished antioxidant defenses such as superoxide dismutase, catalase and glutathione (Junqueira et al. 1988; Videla et al. 1990). Superoxide dismutase activities are reported to decrease by 6 hr after oral lindane dosing and remained depressed for at least 24 hr, with values falling by almost 50% (Junqueira et al. 1988). No distinction has been made between cytosolic Cu-Zn superoxide dismutase and mitochondial Mn superoxide dismutase (Hassan 1988). However, the sample preparation used (Junqueira et al. 1988) produces primarily cytosol, and cytosolic superoxide dismutase accounts for most of the total superoxide dismutase in liver (i.e. L'Abbe et al. 1991). The present study examined lindane effects specifically on Cu-Zn superoxide dismutase activity. No effect was found despite induction of lipid peroxidation.
Animals and experimental procedures. For fig. I , male Sprague Dawley rats (Harlan Sprague Dawley, Indianapolis, U.S.A.), 250 to 300 g, previously fed a standard mixed feed, were given 60 mg/kg, intraperitoneally of lindane in corn oil, or corn oil alone. For table 1, weanlings were fed a semipurified diet (DiSilvestro & Marten 1990) with 6 p.p.m. copper for 6 weeks. Analytical procedures. Lipid peroxidation was assessed as thiobarbituric acid reacting substances (Ohkawa et al. 1979). Cu-Zn superoxide dismutase activity was generally assayed by a modified pyrogallol method after homogenizing livers using a Brinkmann Polytron (Westbury, NY, U.S.A.), and then inactivating Mn superoxide dismutase with ethanol :chloroform (Marklund & Marklund 1974; DiSilvestro & Marten 1990). Superoxide dismutase activity was also assayed in a postmicrosoma1 supernatant (Junqueira et al. 1988), prepared from a homogenate made with a Potter-Elvehjem apparatus, using a nitroblue tetrazolium superoxide dismutase method (Beauchamp 1971). For both superoxide dismutase assays,
* To whom correspondence should be addressed.
units were the sample amounts giving 50% inhibition of color formation. Liver lipid peroxide levels were elevated by about 30%, 16 and 24 hr after lindane injection (fig. 1). This elevation was less than that reported by Junqueira et al. (1988). However, this previous study incubated oxygenated samples at 37" before reaction with thiobarbituric acid (Bernheim et al. 1948). This increases sample thiobarbituric acid reacting substances before initiating the thiobarbituric acid reaction. The method used in our study (Ohkawa et al. 1979) measures only preexisting thiobarbituric acid reacting substances. Cu-Zn superoxide dismutase activities were unchanged at three time points after lindane injection (fig. I). One possible difference between this study and that of Junqueira et al. (1988), could have been the dietary copper levels. Lindane could act like inflammation, a reducer of liver Cu-Zn superoxide dismutase activities when rats are fed 6 p.p.m. copper or less, but not when diets contain 15 p.p.m. copper (DiSilvestro & Marten 1990). However, lindane did not reduce Cu-Zn superoxide dismutase activities in rats fed 6 p.p.m. copper (table I).
-
Liver TBARS & CuZnSOD Activity of Lindane R a t s
..*. SOD
TBARS
160 150 140
0
8
16
24
Hours Fig. 1. Effects of lindane (60 mg/kg, intraperitoneally) on hepatic thiobarbituric acid reacting substances (TBARS) per g liver and Cu-Zn superoxide dismutase (SOD) activity units per g liver. Values are the means from 3 rats-frS.E.M.TBARS were significantly different from controls at 16 and 24 hr (p
