The current study was designed to investigate the effect of Red ginseng extract on development of colonic aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH) in male F344 rats. Five-week old animals received subcutaneous injections of DMH (30 mg/kg body weight) four times, for a period of two weeks in order to induce ACF. The animals were divided into groups fed a diet containing red ginseng extract at three different doses (0.5, 1.0, and 2.0%), respectively. Animals were evaluated for the total number of ACF and total aberrant crypts (AC) per colon detected from methylene blue-stained rat colon. ACF formation was observed in animals in the DMH-treated group. Four-time treatment with DMH induced mean 265.8±48.3 ACF/colon composed of a total of 608.8±110.9 aberrant crypts AC/colon. The numbers of ACF and AC induced by DMH were decreased to 204.4±29.3 and 464.7±70.3 by treatment with 0.5% red ginseng extract. In addition, the number of large ACF (≥4 AC/ACF) was suppressed from 39.9±10.6 ACF/colon in control to 28.5±5.3 ACF/colon in 0.5% red ginseng extract. These results suggested that red ginseng extract exerted a chemopreventive effect on DMH-induced colon cancer by inhibiting development of ACF and AC in F344 rats.

The effects of isotonic saline on corneal penetration, thickness, and injury, as well as lacrimal secretion in a rat model of dry eye were investigated, in comparison with distilled water. Male Sprague-Dawley rats received intraperitoneal administration of atropine sulfate (20 mg/kg) and their eyes were exposed to dry (relative humidity 25-35%) air flow (2.4 m/sec), under Zoletil anesthesia, for 5 hr to induce dry eye. During the period of dry eye induction, distilled water or isotonic saline (5 μl) was instillated onto the cornea every 30 min. Corneal penetration was measured through fluorescein dye quantification, and corneal thickness and injury were examined under a microscope. Lacrimal (tear) secretion and mucin-like glyocoprotein excretion from goblet cells were measured using the Schirmer test and microscopy, respectively. In dry eye rats treated with distilled water, corneal thickness, tear secretion, and mucin-like glycoprotein excretion were decreased to 74.0%, 74.1%, and 46.3% of normal levels, respectively, resulting in marked corneal injury and a significant increase in corneal penetration. In comparison, treatment with isotonic saline resulted in recovery of lacrimal secretion, in spite of a slight improvement of mucin-like glycoprotein excretion, and thereby prevented corneal penetration of fluorescein by 10%. The results indicate that repeated instillation of isotonic saline could provide slightly greater protection from corneal injury, compared with distilled water by facilitating lacrimal secretion, in addition to relief of inconvenience and pain.

Four-week repeated-dose toxicity of Misaengtang (MST) was evaluated according to Toxicity Test Guideline of Korea Food and Drug Administration using 6-week-old Sprague-Dawley rats. Based on the results of preliminary single-dose toxicity study, confirming safety up to an upper-limit dose, MST was dissolved in drinking water and orally administered at doses of 500, 1,000, or 2,000 mg/kg for 28 days. All doses including the upper-limit limited dose (2,000 mg/kg) of MST did not cause any abnormalities of rats, including mortality, clinical signs, body weight gain, feed/water consumption, necropsy findings, organ weights, hematology and blood biochemistry. Rather, high doses (1,000-2,000 mg/kg) of MST reduced the serum levels of alanine transaminase, aspartate transaminase, creatinine phosphokinase, lactate dehydrogenase and triglycerides, in addition to an increase in glucose, indicative of protective effects on hepatic and muscular injuries. Both maximum-tolerable dose and no-observed-adverse-effect level were not determined. The results indicate that long-term intake of high-dose MST might not induce general adverse-effects.