Chronological observations of intestinal histopathology in rats (Rattus norvegicus) infected with Centrocestus caninus.

Intestinal pathological enzyme activity changes were studied chronologically in rats after Centrocestus caninus infection. A single inoculation of 300 metacercariae isolated from the gills of goldfish (Carassius auratus), was orally administered to male rats (n = 15). Uninfected animals were used as controls (n = 5). At days 3, 7, 14, 21, and 28 post-infection (PI), three infected rats, and one from each control group, were sacrificed. The duodenum, jejunum, and ileum were removed separately and fixed in 10% formalin and 10% cold formal calcium solution for histopathological and alkaline phosphatase activity investigations, respectively. The worms were found intruded into the intervillous space of the mucosa and the mucosa showed villous atrophy, crypt hyperplasia and stromal inflammation with inflammatory cell accumulations. Alkaline phosphatase (ALP) activity also showed retardation. However, it seemed that these phenomena would return to normal at the end of the experiment. It can be concluded, from our data, that C. caninus could cause mild histopathological alterations and reduce ALP activity in the small intestines.

Effect of Kaempferia parviflora Wall. ex. Baker on sexual activity of male rats and its toxicity.

Kaempferia parviflora Wall. Ex. Baker (Krachaidum) has long been used among Thai men for sexual enhancement. The aim of this study was to determine the effect of K. parviflora ethanolic extract on the sexual behavior of male rats and its toxicity. The experiment was divided into three groups of rats given K. parviflora extract at doses of 60, 120, and 240 mg/kg BW for 60 days, whilst a control group received distilled water at 1 ml/day per oral. The results showed that all groups of male rats had significantly higher courtship behavior during the first 10-minute period of observation than in the 2nd and 3rd 10-minute periods, except those receiving the highest dose of K. parviflora. They revealed the same amount of courtship behavior throughout a whole 30-minute period, which was significantly lower than the control group. There was no significant difference between treated and control groups in other sexual behaviors; mount frequency (MF), intromission frequency (IF), mount latency (ML), or intromission latency (IL). Toxicological study revealed no significant difference of hemoglobin, WBC or differential cell count. All dosages had no effect on kidney and liver function, according to the normal values of blood urea nitrogen (BUN), creatinine (Crea), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Nevertheless, the histopathological study showed a morphological change in the liver. It was concluded that K. parviflora extract at 240 mg/kg BW reduced the time in the first 10 mintues of rat courtship behavior and the use of high and chronic doses of K. parviflora in humans should be considered inadvisable.

Toxicological evaluation of Cladophora glomerata Kützing and Microspora floccosa Thuret in albino rats.

This study aimed to evaluate the toxicity of Cladophora glomerata and Microspora floccosa ethanolic extracts in rats. Acute toxicity was tested with a single oral administration of the extract at a dose of 25 g/kg bd wt. Mortality, behavior, amount of food intake, body weight, and any abnormalities of the visceral organs, were observed. The results showed that the extract caused neither mortality, nor abnormalities. Subchronic toxicity was tested by administering the extract at doses of 0.5 g/kg and 1.0 g/kg for 60 days. Differences in body weight, hematology and blood biochemistry (alanine aminotransferase, ALT; aspartate aminotransferase, AST; blood urea nitrogen, BUN and creatinine, Cre) were not detected among the control and treatment groups. Although the packed cell volume of the male rats treated with 1.0 g/kg extract was significantly lower than the controls (p< or =0.05), the level was in the standard range for rat hematocrit.

Safety evaluation of aqueous extracts from Aegle marmelos and Stevia rebaudiana on reproduction of female rats.

The purpose of this study was to evaluate the safety of a Thai medicinal plant, Aegle marmelos, and a non-caloric sweetener, Stevia rebaudiana, on the reproduction of female rats. Female rats were treated orally with aqueous extract of A. marmelos (6%) and S. rebaudiana at various concentrations (0, 0.2, 1, or 10%) for 60 days (1 ml/day) before mating. The control rats received only distilled water. At the end of the treatment period, treated females were mated with untreated males and the effects on reproduction were examined at day 14 of pregnancy. No notable abnormalities were observed in any of the pregnant rats. The number of corpus lutea, implanted and dead fetuses, as well as the sizes of the fetuses in the treated rats were not significantly different from those of the controls. Based on these results, it may be concluded that aqueous extracts of A. marmelos and S. rebaudiana at the concentrations used in this study do not alter the reproduction of female rats.

Mucosal mast cell responses in rats (Rattus norvegicus) experimentally infected with Centrocestus caninus.

Mucosal mast cell (MMC) responses and worm recovery rates in rats experimentally infected with Centrocestus caninus were investigated. Metacercariae of C. caninus, procured from goldfish, Carassius auratus, were orally administered to twenty-five male rats (300 metacercariae each rat). The infected rats were sacrificed on days 3, 7, 14, 21 and 28 post-infection (PI) along with the control rats. Worm recovery was performed from each part of small intestine. To investigate MMC, duodenal, jejunal and ileal paraffinized-tissue sections were processed and stained with 1% alcian blue and 0.5% safranin-O. The average worm recovery rates were 42.8, 37.7, 21.2, 12.5 and 3.7% on days 3, 7, 14, 21 and 28 PI, respectively. The majority of the worms (98.9%) were collected from the duodenum and jejunum. The MMC numbers in the infected rats were significantly higher than those of the controls (p<0.05). A peak level was observed on days 14 PI and the numbers gradually decreased thereafter. The results reveal that MMC plays an important role in the expulsion of C. caninus from the host intestine. A more precise description of the role the MMC plays in helminth expulsion is still needed to understand the mechanism of host defense against intestinal helminthic infection, along with other effector cells, such as goblet cells.

The toxicity of a crude enzyme extract from Gliomastix murorum in Swiss Albino mice.

A crude enzyme extract from a fungus, Gliomastix murorum, could be used in the synthesis of oligosaccharides that are essential to the food and drug industries. This extract may contaminate such products and lead to serious health problems. An investigation on the possible toxicity and mutagenic effect of the extract from this fungal isolate was carried out in Swiss Albino mice. One hundred and 50% of the crude enzyme extract were injected intraperitoneally into the mice every 2 days for 30 days. Normal saline (0.9%), cultivation medium, and cyclophosphamide (80 mg/kg body weight) were given to the control groups. The results indicated that the white blood cell count, serum creatinine, and uric acid of the treated mice were significantly higher than those of the controls (p<0.05), whereas the serum urea-N was lower. For the micronucleus test, mice treated with the extract, especially the group received 100% crude enzyme extract, showed a higher number of micronuclei in polychromatic erythrocytes, as compared to controls. Nevertheless, the micronucleus values were not as high as those found in mice treated with cyclophosphamide, the mutagenic agent. It can be concluded from the results that crude enzyme extract had minor toxic effects on various organ systems tested; more extensive investigation on the safe use of this extract is therefore necessary.

Susceptibility of rodents to Stellantchasmus falcatus infection.

Two rodent hosts, rats (Rattus norvegicus) and mice (Mus musculus), were examined for their susceptibility to Stellantchasmus falcatus infection. The metacercariae were recovered from half-beaked fish, Dermogenus pusillus, collected from Hang Dong District, Chiang Mai Province. A single inoculation of three hundred metacercariae was orally conducted with male rats (n=15) and mice (n=15). Uninfected animals were used as controls (n=5). At days 3, 7, 14, 21 and 28, post-infection (PI), three rats and mice, also one from each control group, were sacrificed for adult worm recovery, and the blood was drawn by heart puncture and prepared for white blood cell and eosinophil counts. The results showed that adult worm recovery gradually decreased after day 21 PI in the rats, whereas, reduction in the mice was found after day 7 PI and the adult worms completely disappeared at day 28 PI. Hematologically, total white blood cell counts in two kinds of infected hosts were not statistically different from those of controls. However, eosinophil counts of infected rats slightly increased during days 7-14 PI, and started to decrease at day 21 PI. A similar finding was observed in the infected mice. From these results, it can be concluded that the rat is a more suitable host for S. falcatus than the mouse. To understand the mechanisms implicated in determining host susceptibility, intensive studies are required.