NEURONAL DAMAGE IN BRAINS OF FIRST- AND SECOND-GENERATION PUPS BORN TO HYPOTHYROID WISTAR RATS

Abstract

OBJECTIVE: To study neuronal damage in brains of first and second-generation pups, born to hypothyroid Wistar rats. METHODS: Ten female adult Wistar rats, randomized into two equal groups-propylthiouracil (Group-P) and control (Group-C) were allowed to conceive. Group-P was given oral propylthiouracil throughout gestational period and weaning until 22nd day. Nine offspring from group-C (C/FC) and group-P (P/FC) were sacrificed on 22nd day of life to collect blood and brain samples. The dams of group-P (group-PP) were allowed to conceive and continued with propylthiouracil treatment throughout gestation and weaning. Their nine offsprings (PP/FC) were sacrificed on 22nd day. Serum levels of triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH) were measured. Brain weight, apoptotic cell count (ACC) of Purkinje cells of cerebellar cortex and Pyramidal cells of hippocampus were documented. RESULTS: Mean TSH levels were 21±3ηg/dl, 23.3±3.5ηg/dl and 10±2.1ηg/dl in P/FC, PP/FC and C/FC respectively (p=0.003). Mean T4 was 31.7±1.2ηg/dl, 30.3±1.3ηg/dl and 36.3±0.9ηg/dl in P/FC, PP/FC and C/FC respectively (p=0.030). Mean brain weights was 1.21±0.21 mg, 1.20±0.41 mg and 1.42±0.01 mg group in P/FC, PP/FC and C/FC respectively (p>0.05). The normal Pyramidal and Purkinje cell count was low in P/FC and PP/FC groups compared to C/FC group (p<0.05). The ACC of Pyramidal and Purkinje cells was high in P/FC and PP/FC groups compared to C/FC group (p<0.05). CONCLUSION: Maternal hypothyroidism adversely affected the morphology of Pyramidal and Purkinje cells by enhancing apoptosis, which increased further in second generation pups.