Protective effect of a polyherbal bioactive fraction in propylthiouracil-induced thyroid toxicity in ratsby modulation of the hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal axes

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Hypothyroidism is the most frequent toxic effect of a large variety of chemical compounds.

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The polyherbal bioactive fraction exhibited a pro-thyroid effect in hypothyroidic rats.

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The polyherbal fraction restored the propylthiouracil-depleted thyroid hormone levels significantly.

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The polyherbal fraction may act through multiple mechanisms to exhibit a pro-thyroid effect.

Hypothyroidism is the most frequent consequence of the interaction of a large variety of drugs, environmental pollutants and industrial chemicals with the thyroid gland. It is associated with diminished endocrine function which may lead to hyperlipidemia, diabetes, Alzheimer’s disease, weight gain, and other metabolic disorders. The present study evaluates the pro-thyroid activity of a bioactive fraction from a polyherbal teabag in rats with hypothyroidism induced by propylthiouracil. The teabag was formulated to stimulate synthesis and/or release of T4 and affectthe conversion of T4 to T3. Phytoconstituents of the polyherbal teabag are potent antioxidants that may be responsible for the pro-thyroid activity. The tea-extract (1000 mg) was found to contain 1076 μg of gallic acid and 1131 μg of rutin from HPTLC analysis. Rats received propylthiouracil (8 mg/kg) for the first 15days followed by the polyherbal tea-extract (500, 1000 and 1500 mg/kg), the standard drug levothyroxine (0.1 mg/kg), aerobic exercise, and a combination of tea-extract (1000 mg/kg) and aerobic exercise daily along with propylthiouracil for the next 30 days. Finally, rats received their respective treatments alone without propylthiouracil for 15 more days. Lipid profile and levels of glucose, insulin, T3, T4, TSH, cortisol, homocysteine, creatinine, uric acid, malondialdehyde, glucose-6 phosphatase, and endogenous antioxidants were determined. All treatments attenuated significantly the propylthiouracil-elevated TSH, homocysteine, creatinine, uric acid, glucose-6-phosphatase, insulin, and malondialdehyde levels, and restored favorably the propylthiouracil-altered lipid profile, T3, T4, and endogenous antioxidant levels. The polyherbal tea-extract (1000 and 1500 mg/kg) treatment and thecombination treatment of tea-extract (1000 mg/kg) with aerobic exercise displayed significant restoration of the suboptimalthyroid function. This may be due to a favorablemodulation ofthe hypothalamic-pituitary–thyroid and the hypothalamic–pituitary–adrenal axes.

Leukoence­phalomalacia in a two-year-old Thoroughbred colt

Leukoencephalomalacia is a disease of horses and donkeys caused by the ingestion of the mycotoxin fumonisin produced by the fungus F. proliferatum. In June 2015, a 2-year-old Thoroughbred colt kept in a feedlot around Tehran, Iran was presented with severe neurologic signs for clinical examination. Based on clinical evidences, history of ingestion of inappropriately stored commercially prepared feedlot concentrates and post mortem examinations, equine leukoencephalomalacia was suspected. Histopathologic findings, the results of feed fungal culture and mycotoxin analysis confirmed the disease.