title: Growth plate changes associated with Hypothyroidism amongst the pre and postnatal rats.
abstract: OBJECTIVE
  This study is intended to examine the effect of hypothyroidism and thyroxin replacement on axial and appendicular skeletal growth, growth plate thickness and to observe associated microscopic changes within the growth plates.
  
  
  METHODS
  Experimental albino rats were developed with carbimazole and carbimazole plus thyroxin. Animals were administered with these drugs throughout pregnancy (prenatally) and for a period of six weeks, postnatally. At the end of the experiment the animals were sacrificed, measured and processed to demonstrate the bony and cartilaginous parts. Ulna and tibia of both sides were removed and processed for light microscopy and growth plate measurement.
  
  
  RESULTS
  At the end of the experiment, reduction in the crown rump length was observed in the carbimazole treated animals. It was 8.77%, 13.26% and 7.25% in the prenatal, two weeks and six weeks age group animals respectively. In carbimazole plus thyroxin treated animals, this reduction was 3.22%, 2.94% and 3.42%, when compared to their age matched controls. Reduction in the thickness of the Epiphyseal growth plate (EGP) was 16.89% and 12.80% in the ulna of the two and six weeks age group and 18.06 % and 15.65% in the tibia of the these animals respectively. The carbimazole plus thyroxin treated animals showed an increase in the thickness of EGP as compared to their age-matched controls though the crown rump length of these animals was less than the controls. Prenatally treated hypothyroid rats showed disrupted growth plates without any well-formed microscopic zones.
  
  
  CONCLUSIONS
  The results of this study showed that the pre and postnatally, carbimazole induced hypothyroidism and its replacement therapy affected the axial and appendicular skeletal growth. Proximal limb bones of the prenatally induced hypothyroid animals showed the greatest skeletal change in this study.
authors.affiliation: Professor, Department of Anatomy and Histology, College of Medicine, Qassim University, Saudi Arabia.
authors.forename: Masood Ahmed
authors.initials: MA
authors.lastname: Shaikh
authors.forename: Zahid
authors.initials: Z
authors.lastname: Naeem
authors.forename: Abd Alrahman
authors.initials: AA
authors.lastname: Alshahat
authors.forename: Farooque Ahmed
authors.initials: FA
authors.lastname: Shaikh
authors.forename: Shahan
authors.initials: S
authors.lastname: Arif
keywords: Growth plate; Hypothyroidism; Prenatal growth; Thyroid dysfunction; skeletal growth
references.citation: Acta Endocrinol (Copenh). 1978 Nov;89(3):567-79
references.pmid: 212918
references.citation: J Anat. 1981 Aug;133(Pt 1):37-47
references.pmid: 7319898
references.citation: J Endocrinol. 2011 Jun;209(3):261-72
references.pmid: 21292729
references.citation: J Bone Miner Res. 2005 Feb;20(2):294-304
references.pmid: 15647824
references.citation: N Engl J Med. 1994 Oct 20;331(16):1072-8
references.pmid: 8090169
references.citation: Eur J Pediatr. 1996 May;155(5):362-7
references.pmid: 8741031
references.citation: Trends Endocrinol Metab. 2003 Oct;14(8):356-64
references.pmid: 14516933
references.citation: Anat Rec. 1949 Aug;104(4):445-63
references.pmid: 18143229
references.citation: Endocrinology. 1993 Nov;133(5):2403-6
references.pmid: 8404692
references.citation: J Clin Endocrinol Metab. 2000 Nov;85(11):3975-87
references.pmid: 11095417
references.citation: Mol Cell Endocrinol. 2003 Dec 31;213(1):1-11
references.pmid: 15062569
references.citation: J Anat. 1995 Feb;186 ( Pt 1):175-85
references.pmid: 7649813
references.citation: N Engl J Med. 1989 Jul 6;321(1):13-6
references.pmid: 2733742
references.citation: J Anat. 1996 Apr;188 ( Pt 2):383-93
references.pmid: 8621338
references.citation: N Engl J Med. 1988 Mar 10;318(10):599-602
references.pmid: 3344006
references.citation: Thyroid. 1999 Jul;9(7):661-5
references.pmid: 10447011
references.citation: Acta Endocrinol (Copenh). 1989 Jan;120(1):20-30
references.pmid: 2911938
references.citation: J Pak Med Assoc. 2003 Jan;53(1):18-21
references.pmid: 12666846
references.citation: Endocrinology. 1989 Feb;124(2):937-45
references.pmid: 2912707
references.citation: J Clin Endocrinol Metab. 1981 Sep;53(3):498-501
references.pmid: 7263836
references.citation: J Clin Endocrinol Metab. 2001 Jun;86(6):2349-53
references.pmid: 11397821
references.citation: Endocrinology. 1992 Jul;131(1):357-65
references.pmid: 1612015
references.citation: Clin Endocrinol (Oxf). 2004 Sep;61(3):285-98
references.pmid: 15355444
references.citation: Trends Endocrinol Metab. 2012 Apr;23(4):155-62
references.pmid: 22169753
references.citation: Mol Genet Metab. 2002 Jan;75(1):17-30
references.pmid: 11825060
references.citation: Mol Endocrinol. 2008 Feb;22(2):501-12
references.pmid: 17932107
references.citation: Endocrinology. 1993 May;132(5):2056-64
references.pmid: 8477656
references.citation: J Pediatr Endocrinol Metab. 2003 May;16 Suppl 3:607-12
references.pmid: 12795361
references.citation: Neuro Endocrinol Lett. 2007 Aug;28(4):484-8
references.pmid: 17693962
references.citation: J Anat. 1988 Aug;159:173-9
references.pmid: 3248965