Histopathological and immunohistochemical study of the protective effect of triptorelin on the neurocytes of the hippocampus and the cerebral cortex of male albino rats after short-term exposure to cyclophosphamide

Abstract

Chemotherapy treats many types of cancer effectively but it often causes side effects. Chemotherapy works on active cells, such as cancer cells, and some healthy cells. Side effects happen when chemotherapy damages these healthy cells. Today, many more drugs are available to treat side effects than in the past. Triptorelin (Decapeptyl) is a gonadotropin-releasing hormone agonist that is reported to have many therapeutic effects besides being an anti-cancer agent. In the current study, intraperitoneal cyclophosphamide (65 mg/kg/day) was administered for 4 weeks to induce marked dystrophic changes in the cerebral cortex and hippocampus of male albino rats. After 4 weeks, we observed significant degeneration of neurocytes with dystrophic changes. Subcutaneous triptorelin (0.05 mg/kg/day) for 4 weeks significantly improved histological signs of degeneration and apoptosis. Anti-Bcl2 staining of sections of the cerebral cortex and hippocampus showed that the apoptotic index was increased. This finding was confirmed by the anti-p53 staining, which showed a significant decrease in the apoptotic index. Ultimately, such improvements were accompanied by significant restoration of normal brain histology, as revealed by hematoxylin and eosin. In conclusion, triptorelin can reverse the apoptotic changes induced by cyclophosphamide therapy, which is more marked in the hippocampus than cerebral cortex.

Keywords: cerebral cortex; cyclophosphamide; hippocampus; p53; triptorelin.

Figure 1

Photomicrograph of the cerebral cortex of a cyclophosphamide-treated rat (Group II) showing neurons with dystrophic changes in the form of shrunken hyperchromatic, irregular with chromatolysis and abnormal Nissl granule distribution (arrows), with dilated blood vessel (*), and degenerate and vacuolated neurocytes (arrow heads). Stain: hematoxylin and eosin; magnification: 400×.

Figure 2

Photomicrograph of an anti-Bcl2-stained section of the cerebral cortex of a cyclophosphamide-treated rat (Group II) showing brown immunoreactive staining of perinuclear membranes of neurocytes. Low immunoreactivity of apoptotic cells in cerebral cortex of a cyclophosphamide-treated rat (arrows). Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 3

Photomicrograph of anti-p53-stained section of the cerebral cortex of a cyclophosphamide-treated rat (Group II) showing brown positively immunoreactive neurocyte nuclei, with marked expression of positively immunoreactive apoptotic cells (arrows). Stain: immunohistochemical anti-p53 staining; magnification: 400×.

Figure 4

Photomicrograph of hippocampus of a cyclophosphamide-treated rat (Group II) showing decreased thickness of pyramidal cell layer in the CA3 region, with increased apoptotic neurons with dystrophic changes in the form of shrunken hyperchromatic, irregular with chromatolysis and abnormal Nissl granule distribution (arrows) with dilated blood vessel (*), and degenerated and vacuolated neurocytes (arrow head). Stain: hematoxylin and eosin; magnification 400×.

Figure 5

Photomicrograph of an anti-Bcl2-stained section of the hippocampus of a cyclophosphamide-treated rat (Group II) showing brown immunoreactive staining of perinuclear membranes of neurocytes. There was less positive immunoreactivity in some apoptotic cells (arrows). Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 6

Photomicrograph of an anti-p53-stained section of the hippocampus of a cyclophosphamide-treated rat (Group II) showing brown immunoreactive staining of neurocyte nuclei, with marked expression of apoptotic cells (arrows). Stain: immunohistochemical anti-p53 staining; magnification: 400×.

Figure 7

Photomicrograph of cerebral cortex of a triptorelin-treated rat (group III) showing near normal neurons, with central large vesicular nuclei, containing one or more nucleoli, and peripheral distribution of Nissl granules (arrows). Stain: hematoxylin and eosin; magnification: 400 ×.

Figure 8

Photomicrograph of an anti-Bcl2-stained section of the cerebral cortex of a triptorelin-treated rat (Group III) showing positive immunoreactivity of neurons in the form of brown staining of neurocyte perinuclear membranes (arrows). Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 9

Photomicrograph of an anti-p53-stained section of the cerebral cortex of a triptorelin-treated rat (Group III) showing negative immunoreactivity of neurons in the form of brown staining of cerebral cortex neurocyte nuclei (arrows). Stain: immunohistochemical anti-p53 staining; magnification: 400×.

Figure 10

Photomicrograph of hippocampus of a triptorelin-treated rat (Group III) showing near normal thickness of the pyramidal cell layer of the CA3 region, with normal neurons (arrows). Stain: hematoxylin and eosin; magnification: 400×.

Figure 11

Photomicrograph of an anti-Bcl2-stained section of the hippocampus of a triptorelin-treated rat (Group III) showing positive immunoreactivity of neurocyte perinuclear membranes (arrows) Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 12

Photomicrograph of an anti-p53-stained section of hippocampus of triptorelin-treated rats (Group III) showing negative immunoreactivityin neurocyte nuclei (arrows) Stain: immunohistochemical anti-p53 staining; magnification: 400×.

Figure 13

Photomicrograph of cerebral cortex of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing near normal neurons with central large vesicular nuclei, containing one or more nucleoli, and peripheral distribution of Nissl granules (arrows head), and small number of neurons with dystrophic changes in the form of shrunken hyperchromatic, irregular (arrows), and abnormal Nissl granules distribution. Stain: hematoxylin and eosin; magnification: 400×.

Figure 14

Photomicrograph of an anti-Bcl2-stained section of the cerebral cortex of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing positive immunoreactivity of most of the neurocyte perinuclear membranes neurons (arrows), with a small number of apoptotic neurons with negative immunoreactivity (arrow head). Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 15

Photomicrograph of an anti-p53-stained section of the cerebral cortex of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing negative immunoreactivity in the nuclei of the neurons (arrows). Stain: immunohistochemical anti-p53 staining; magnification: 400 ×.

Figure 16

Photomicrograph of the hippocampus of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing normal neurons n the pyramidal cell layer of the CA3 region (arrows), with a small number of apoptotic neurons (arrow head). Stain: hematoxylin and eosin; magnification: 400×.

Figure 17

Photomicrograph of an anti-Bcl2-stained section of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing brown staining of hippocampal neurocyte perinuclear membranes. Positive immunoreactivity of most neurons (arrows), with a small number of apoptotic neurons with negative immunoreactivity (arrow head). Stain: immunohistochemical anti-Bcl2 staining; magnification: 400×.

Figure 18

Photomicrograph of an anti-p53-stained section of the hippocampus of a cyclophosphamide-treated rat receiving triptorelin (Group IV) showing brown staining of neurocyte nuclei, indicating positive immunoreactivity (arrows). Stain: immunohistochemical anti-p53 staining,; magnification: 400×.

Figure 19

Changes in the apoptotic index of the neurocytes of the cerebral cortex with (A) anti-p53 (B) anti-Bcl2 staining in adult rats in the control and experimental groups.

Figure 20

Changes in the apoptotic index of the neurocytes of the hippocampus with (A) anti-p53 (B) anti-Bcl2 staining in adult rats in the control and experimental groups.