[Subacute toxicity study of lentinan in rats. 5-week intravenous treatment (author's transl)]

Male and female JCL : SD rats were treated intravenously with lentinan in 5% mannitol solution at dose levels of 0, 0.03, 3.0 and 30.0 mg/kg/day for 5 weeks. Rats receiving 0.3, 3.0 and 30.0 mg/kg/day showed reddening in ear, tail and scrotum and edema in legs and scrotum after day 3 of treatment. Males receiving 30.0 mg/kg/day gained less body weight than control. Occult blood was found in the urine of rats receiving 30.0 mg/kg/day. With regard to haematology, rats from the treatment groups had low mean values relating to red blood cell count, packed cell volume and haemoglobin, while high white blood cell count were recorded for these rats. Biochemical examinations revealed decreases in albumin level and A/G ratio and increases in beta-globulin and gamma-globulin levels for rats from the treatment groups. Slightly high values of BUN were showed for rats receiving 30.0 mg/kg/day. Organ weight analysis showed dose-dependent increase in the spleen, liver and adrenal. Histopathological changes attributable to treatment included (1) changes in reticuloendothelial system such as proliferation of reticular cells and micronodule of epithelioid cells in the spleen, liver and lymph nodes; (2) arteritis in many organs especially notable in epididymis, intestines and mesentery; (3) haemorrhagic changes in lung, intestines and urinary bladder and secondary changes such as increased chronic nephropathy, hypospermatogenesis, spermatic granuloma in epididymis and granulomatous inflammation in ear, tail and scrotum. The maxim safe dose was estimated to be smaller than 0.03 mg/kg/day for males and 0.03 mg/kg/day for females in the present study.