Aqueous extract of black tea (Camellia sinensis) prevents ethanol+cholecystokinin-induced pancreatitis in a rat model

Black Tea Extract (BTE), a phytocompound has been attributed with a plethora of health-promoting actions. We have previously demonstrated that BTE inhibits chronic hepatitis in a rat model induced with high-fat and ethanol (EtOH). This study reports that BTE prevents altered pancreatic acinar cell functions, oxidative stress, inflammatory changes and DNA damage in the EtOH+cholecystokinin (CCK)-induced model of pancreatitis. The EtOH+CCK model rats were administered with BTE, and were examined the activity of pancreatic digestive enzymes (amylase and lipase), proinflammatory cytokines (IL-6 and TNF-alpha), oxidative and antioxidative enzymes (nitric oxide, NO; malondialdehyde, MDA; superoxide dismutase, SOD; catalase, CAT), antioxidant level (glutathione, GSH), histopathological changes and the integrity of genomic DNA. Results show that because of chronic EtOH treatment, serum level of amylase and lipase (two biomarkers for pancreatitis) and pancreatic levels of MDA and NO (two biomarkers of oxidative stress) increased significantly, which could be effectively blunted by BTE. BTE could normalize EtOH+CCK-induced suppressed activities of SOD and CAT, and GSH content of pancreatic tissue. Also, histopathological and inflammatory changes during EtOH+CCK-induced pancreatitis could be blunted by BTE. Furthermore, BTE could effectively reduce EtOH+CCK-induced increase in DNA fragmentation and damage. These findings suggest that BTE prevents pancreatitis caused by chronic EtOH+CCK toxicity presumably by enhancing antioxidant, anti-inflammatory and antiapoptotic activity in rats.     

Anti-inflammatory activity of tea (Camellia sinensis) root extract

Pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (Camellia sinensis) root extract (TRE). TRE was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its LD50 dose of 100 mg/kg i.p. It was found that TRE inhibited the arachidonic acid-induced paw oedema in rats which indicated that TRE produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. TRE also enhanced peritoneal cell count and the number of macrophages in normal mice. It is plausible that the saponins present in TRE may be responsible for these activities of TRE.     

Studies on black tea (Camellia sinensis) extract as a potential antioxidant and a probable radioprotector

Positive health effects of tea (Camellia sinensis) on a wide range of physiological problems and diseases are well known and are in part due to its copious antioxidant content. The effect of black tea extract (BTE), which is rich in polyphenolic antioxidants, against the consequences of radiation exposure has not been properly identified. The functional properties of BTE were analyzed and its radioprotective effect on V79 cells was explored in the present study. BTE scavenged free radicals and inhibited Fenton reaction-mediated 2-deoxyribose degradation and lipid peroxidation in a dose-dependent fashion, establishing its antioxidant properties. The radioprotective effects of BTE on strand break induction in pBR322 plasmid DNA were 100 % at 80 μg/ml and higher. In V79 cells, BTE was effective in decreasing the frequency of radiation-induced micronucleated cells and the yields of reactive oxygen species (ROS) and also in restoring the integrity of cellular mitochondrial membrane potential significantly. BTE exerted maximum protection against radiation-induced damage in V79 at a dose of 5 μg/ml. Due to the functional properties of BTE-flavonoids, which have been identified by HPLC, it is envisaged that the key player in radioprotection is elimination of ROS.     

Idiopathic megaesophagus in a rat (Rattus norvegicus)

Necropsy and histopathologic examination of a rat (Rattus norvegicus) revealed megaesophagus and gangrenous bronchopneumonia. The esophageal dilitation, mural atrophy with persistence of neural structures, regurgitation and bronchopneumonia seen in this case were similar to findings in other animals with megaesophagus.     

Skull growth in the albino rat (Rattus norvegicus)

A longitudinal study of growth in the rat skull, based on serial radiographs, has shown that by the age of one month after birth, the braincase attains some 93% of its adult (fifth-month) size whilst the facial skeleton and mandible attain but 75% of their adult size. By the third month, growth in the braincase has virtually ceased, whereas significant facial growth continues until the age of five months.     

Hepatoprotective effect of green tea (Camellia sinensis) extract against tamoxifen-induced liver injury in rats

Tamoxifen citrate (TAM), is widely used for treatment of breast cancer. It showed a degree of hepatic carcinogenesis. The purpose of this study was to elucidate the antioxidant capacity of green tea (Camellia sinensis) extract (GTE) against TAM-induced liver injury. A model of liver injury in female rats was done by intraperitoneal injection of TAM in a dose of 45mg Kg(-1) day(-1), i.p. for 7 successive days. GTE in the concentration of 1.5 %, was orally administered 4 days prior and 14 days after TAM-intoxication as a sole source of drinking water. The antioxidant flavonoid; epicatechin (a component of green tea) was not detectable in liver and blood of rats in either normal control or TAM-intoxicated group, however, TAM intoxication resulted in a significant decrease of its level in liver homogenate of tamoxifenintoxicated rats. The model of TAM-intoxication elicited significant declines in the antioxidant enzymes (glutathione-S-transferase,glutathione peroxidase, superoxide dismutase and catalase) and reduced glutathione concomitant with significant elevations in TBARS (thiobarbituric acid reactive substance) and liver transaminases; sGPT (serum glutamate pyruvate transaminase) and sGOT (serum glutamate oxaloacetate transaminase) levels. The oral administration of 1.5 % GTE to TAM-intoxicated rats, produced significant increments in the antioxidant enzymes and reduced glutathione concomitant with significant decrements in TBARS and liver transaminases levels. The data obtained from this study speculated that 1.5 % GTE has the capacity to scavenge free radical and can protect against oxidative stress induced by TAM intoxication. Supplementation of GTE could be useful in alleviating tamoxifen-induced liver injury in rats.     

Polymorphic microsatellite loci of the rat (Rattus norvegicus)

The EMBL and GenBank DNA databases were searched for microsatellite sequences of the rat containing dinucleotide repeats of (CA)_n and (GA)_n. Among those obtained, 23 sequences were analyzed by polymerase chain reaction to examine the size variation of the amplified fragment in inbred rat strains. All of the 23 microsatellite sequences varied in size among the strains tested. The 23 microsatellite loci in a pair of substrains separated from the same progenitor strain were then analyzed. Fragments identical in size were observed in all loci of the two substrains, indicating the stability of the microsatellite over a large number of generations. The microsatellite loci, therefore, should be useful markers for linkage analyses in the rat.     

The major histocompatibility complex of the rat (Rattus norvegicus)

This review of the RT1 complex, the major histocompatibility complex (MHC) of the rat, focuses on genetic, genomic, evolutionary, and functional aspects at the molecular level. The class I, class II, and framework genes are listed. The physical map of the RT1 complex as revealed by analysis of clonal contigs is compared with the human and mouse MHC, and the degree of orthologous relationship is outlined. Elucidation of the RT1 complex provides important information for using the rat as a model of experimental transplantation and complex diseases.     

Genetic control of two esterases of rat plasma (Rattus norvegicus)

Three electrophoretic variants of plasma esterase in the albumin zone, presumably carboxylesterase, have been demonstrated in 250 rats representing a laboratory population of Wistar rats. Electrophoretic variants of the enzyme are believed to be controlled by two codominant alleles at the autosomal locus referred to as Es-2. The variant of carboxylesterase represented by a fast-migrating single band on starch gel electrophoresis is determined by the gene named Es-2 ^a, whereas the slow-migrating variant, represented by two bands, is under control of the allelic gene Es-2 ^b. Animals with Es-2 ^a/Es-2 ^b genotype have three bands of carboxylesterase in the albumin zone. Genetically determined polymorphism of plasma esterase, presumably carboxylesterase, in the prealbumin zone was shown in both laboratory and wild populations of rats. Breeding tests suggest that the gene referred to as Es-1 ^a, responsible for the presence of carboxylesterase in the prealbumin zone, is inherited dominantly, whereas animals homozygous for the allele Es-1 ^b locked this esterase fraction.     

Characterization of Armillaria isolates from tea (Camellia sinensis) in Kenya

Armillaria is a primary root rot pathogen of tea (Camellia sinensis) in Kenya. The main species presently described in this country are A. mellea and A. heimii. A survey covering fourteen districts of Kenya was carried out and forty-seven isolates of Armillaria collected. Cultural morphology, rhizomorph characteristics, somatic incompatibility and features of basidiomata were used to characterize the isolates, together with molecular analysis based on randomly amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS) and the intergenic spacer (IGS) regions and sequence of the IGS region. It can be concluded that two Armillaria species were present and they were different from A. mellea. The first group was morphologically similar to A. heimii but this was contradicted by the molecular data, suggesting that A. heimii could be a complex of several species. The second group was different from the first and morphological and molecular data strongly suggest that it could be a new Armillaria species.     

Sex modifies genetic effects on residual variance in urinary calcium excretion in rat (Rattus norvegicus)

Conventional genetics assumes common variance among alleles or genetic groups. However, evidence from vertebrate and invertebrate models suggests that residual genotypic variance may itself be under partial genetic control. Such a phenomenon would have great significance: high-variability alleles might confound the detection of "classically" acting genes or scatter predicted evolutionary outcomes among unpredicted trajectories. Of the few works on this phenomenon, many implicate sex in some aspect of its control. We found that female genetic hypercalciuric stone-forming (GHS) rats (Rattus norvegicus) had higher coefficients of variation (CVs) for urinary calcium (CV = 0.14) than GHS males (CV = 0.06), and the reverse in normocalciuric Wistar-Kyoto rats (WKY) (CV(♂) = 0.14; CV(♀) = 0.09), suggesting sex-by-genotype interaction on residual variance. We therefore investigated the effect of sex on absolute-transformed residuals in urinary calcium in an F(2) GHS × WKY mapping cohort. Absolute residuals were associated with genotype at two microsatellites, D3Rat46 (RNO3, 33.9 Mb) and D4Mgh1 (RNO4, 84.8 MB) at Bonferroni thresholds across the entire cohort, and with the microsatellites D3Rat46, D9Mgh2 (RNO9, 84.4 Mb), and D12Rat25 (RNO12, 40.4 Mb) in females (P < 0.05) but not males. In GHS chromosome 1 congenic lines bred onto a WKY genomic background, we found that congenic males had significantly (P < 0.0001) higher CVs for urinary calcium (CV = 0.25) than females (CV = 0.15), supporting the hypothesis of the inheritance of sex-by-genotype interaction on this effect. Our findings suggest that genetic effects on residual variance are sex linked; heritable, sex-specific residuals might have great potential implications for evolution, adaptation, and genetic analysis.     

Biochemical genetics of methylglyoxal dehydrogenases in the laboratory rat (Rattus norvegicus)

A genetic locus controlling the electrophoretic mobility of a methylglyoxal dehydrogenase (EC 1.2.1.23) in the rat is described. The locus, designatedMgd1, is expressed in liver and kidney. Inbred rat strains have fixed either alleleMgd1 ^a or alleleMgd1 ^b . Codominant expression is observed in heterozygotes, providing evidence for a tetrameric enzyme structure. Backcross progenies showed the expected 1:1 segregation ratio, and there is evidence thatMgd1 is linked toPep3 andFh1 on chromosome 13. There is also evidence for two additional methylglyoxal dehydrogenases:Mgd2, present in liver and kidney, andMgd3, present only in heart.Supported by the Deutsche Forschungsgemeinschaft (Grant Be 352/18-1).     

Water deficit induced oxidative damage in tea (Camellia sinensis) plants

When the tea (Camellia sinensis) leaf water potential was -1.1 MPa (Moderate water deficit), there was 58% inhibition of photosynthesis accompanied by increased zeaxanthin, malondialdehyde, oxidized proteins and superoxide dismutase activity. When the leaf water potential was -2MPa (severe water deficit), there was nearly complete inhibition of photosynthesis apart from a decrease in chlorophylls, beta-carotene, neoxanthin and lutein. Water deficit at this level caused further conversion of violaxanthin to zeaxanthin, suggesting damage to the photosynthetic apparatus. There were consistent decreases in antioxidants and pyridine nucleotides, and accumulation of catalytic Fe, malondialdehyde and oxidized proteins. It is inferred that, in tea plants, the increase in catalytic Fe and the decrease in antioxidant protection may be involved in the oxidative damage caused by severe water deficit, but not necessarily in the incipient stress induced by moderate water deficit.     

Muscular function and skull growth in the laboratory rat (Rattus norvegicus)

Bilateral masseterectomy in newly-born rats results in a diminution in cranial weight and size. Such reduction affects the facial skeleton to a greater overall extent than the braincase, although in each region it is the dimensions of length that are affected to a greater extent that are those of height or width. Such contrasts are not dependent upon changes in body weight.
Removal of both temporal muscles—a smaller component of the masticatory musculature—results in little change in cranial proportions other than an increase in width of the braincase.
Such findings can be related, first, to contrasts in the timing of growth in the braincase and facial skeleton and, second, to the extent to which muscular function is reduced.